chore(main): release 0.84.0 (#1190)

🤖 I have created a release *beep* *boop*
---


##
[0.84.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.83.0...v0.84.0)
(2026-09-28)


### Features

* **deps:** update Claude SDK
([#1189](https://github.com/agentclientprotocol/claude-agent-acp/issues/1189))
([d5e6f33](d5e6f33046))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: acp-release-bot[bot] <246668977+acp-release-bot[bot]@users.noreply.github.com>

.gitattributes

@@ -0,0 +1,2 @@
+src/tests/acp-scenarios/__snapshots__/** linguist-generated=true
+src/tests/acp-scenarios/origin-main/** linguist-generated=true

.github/workflows/conventional-prs.yml

@@ -0,0 +1,48 @@
+name: Conventional PRs
+
+# Squash merges use the PR title as the commit subject, which is what
+# release-please parses to compute the next version and CHANGELOG entry.
+on:
+  pull_request:
+    branches: [main]
+    # labeled/unlabeled so validation re-runs when `dependencies` is applied.
+    types: [opened, reopened, edited, synchronize, labeled, unlabeled]
+
+permissions: {}
+
+concurrency:
+  group: "conventional-prs-${{ github.event.pull_request.number }}"
+  cancel-in-progress: true
+
+jobs:
+  validate:
+    name: Validate PR title
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      pull-requests: read
+
+    steps:
+      # Config reference: https://github.com/amannn/action-semantic-pull-request#configuration
+      - uses: amannn/action-semantic-pull-request@48f256284bd46cdaab1048c3721360e808335d50 # v6.1.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          # Exactly the types release-please understands. feat/fix/perf/revert/docs
+          # appear in the changelog; the rest are valid but hidden. Any other type
+          # would be dropped silently, so it is rejected here instead.
+          types: |
+            feat
+            fix
+            perf
+            revert
+            docs
+            style
+            chore
+            refactor
+            test
+            build
+            ci
+          # Dependabot titles itself conventionally already; don't block bot PRs.
+          ignoreLabels: |
+            dependencies

.github/workflows/publish.yml

@@ -3,9 +3,29 @@ on:
   push:
     branches:
       - main
+  workflow_dispatch:
+    inputs:
+      channel:
+        description: Which channel to publish
+        required: true
+        default: stable
+        type: choice
+        options:
+          - stable
+          - preview
+      ref:
+        description: Tag or commit to publish
+        required: true
+        type: string
+      publish_npm:
+        description: Publish the package before updating the registry (stable only)
+        required: true
+        default: true
+        type: boolean
 
 jobs:
   release-please:
+    if: ${{ github.event_name == 'push' }}
     runs-on: ubuntu-latest
     environment: release # Optional: for enhanced security
     permissions:
@@ -27,7 +47,11 @@ jobs:
         id: release
         with:
           token: ${{ steps.generate-token.outputs.token }}
-          release-type: node
+          # Do not add release-type here. The action ignores config-file whenever
+          # release-type is set, which silently disables the pre-1.0 versioning
+          # rules in release-please-config.json and lets a breaking change jump
+          # straight to 1.0.0. The node release type is declared in that config
+          # instead, so nothing is lost by leaving this out.
           config-file: release-please-config.json
           manifest-file: .release-please-manifest.json
     outputs:
@@ -38,13 +62,17 @@ jobs:
     name: Publish to npm
     runs-on: ubuntu-latest
     needs: [release-please]
-    if: ${{ needs.release-please.outputs.release_created }}
+    if: ${{ always() && ((github.event_name == 'workflow_dispatch' && inputs.channel == 'stable' && inputs.publish_npm) || needs.release-please.outputs.release_created == 'true') }}
     environment: release # Optional: for enhanced security
     permissions:
       contents: read
       id-token: write
+    outputs:
+      version: ${{ steps.publish.outputs.version }}
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        with:
+          ref: ${{ github.event_name == 'workflow_dispatch' && inputs.ref || github.ref }}
       # Setup .npmrc file to publish to npm
       - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020
         with:
@@ -52,14 +80,179 @@ jobs:
           registry-url: "https://registry.npmjs.org"
       - run: npm ci
       - run: npm run build
-      - run: npm publish
+      - name: Publish
+        id: publish
+        run: |
+          version="$(node -p "require('./package.json').version")"
+          npm publish
+          echo "version=$version" >> "$GITHUB_OUTPUT"
+
+  # Same shape as publish-npm. Tagging is a separate job, so nothing here needs
+  # write access to the repository.
+  publish-npm-preview:
+    name: Publish preview to npm
+    runs-on: ubuntu-latest
+    # Every push to main gets a preview without waiting for CI or release-please,
+    # except release-please's own release merge, which publishes a stable version.
+    # Check the commit author and the generated release subject to avoid publishing
+    # the same tree twice; either match is enough to skip the preview.
+    if: >-
+      ${{
+        (github.event_name == 'workflow_dispatch' && inputs.channel == 'preview') ||
+        (github.event_name == 'push'
+          && github.event.head_commit.author.name != 'acp-release-bot[bot]'
+          && !startsWith(github.event.head_commit.message, 'chore(main): release '))
+      }}
+    # Same environment as the stable job, so the npm trusted-publisher binding holds.
+    # It carries no required reviewers, so previews never wait for an approval.
+    environment: release
+    permissions:
+      contents: read
+      id-token: write # npm OIDC trusted publishing
+    timeout-minutes: 15
+    # Serialise previews so two pushes cannot read the same registry state and compute
+    # the same -preview.N. Job-level rather than workflow-level: a workflow-level group
+    # would also serialise release-please, and cancelling a queued release-please run
+    # means a release PR that silently stops updating. The trade-off is that GitHub
+    # keeps only one run pending per group, so a third push landing while one preview
+    # runs and another waits drops the waiting one — that commit gets no preview, but a
+    # version is never reused.
+    concurrency:
+      group: publish-npm-preview
+      cancel-in-progress: false
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        with:
+          # Publish the exact pushed commit, or the explicitly requested manual ref.
+          ref: ${{ github.event_name == 'workflow_dispatch' && inputs.ref || github.sha }}
+          # Brings the tags the version calculation reads as its floor. The repo is a
+          # few megabytes packed, so a full fetch is cheap and sidesteps every
+          # shallow-clone tag caveat.
+          fetch-depth: 0
+      - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020
+        with:
+          node-version: "lts/*"
+          registry-url: "https://registry.npmjs.org"
+      # Ahead of the version bump, so this still validates the committed lockfile.
+      - run: npm ci
+      - name: Compute the preview version
+        id: preview
+        run: |
+          version="$(node scripts/next-preview-version.mjs)"
+          sha="$(git rev-parse HEAD)"
+          echo "version=$version" >> "$GITHUB_OUTPUT"
+          echo "sha=$sha" >> "$GITHUB_OUTPUT"
+          echo "Preview \`$version\` from \`$sha\`" >> "$GITHUB_STEP_SUMMARY"
+      - name: Apply the version to the working tree only
+        # Never committed: package.json and .release-please-manifest.json on main stay
+        # release-please's to own, and this only changes what goes into the tarball.
+        # `npm version` keeps package-lock.json's version fields in step, and
+        # --no-git-tag-version skips every git operation.
+        run: npm version "${{ steps.preview.outputs.version }}" --no-git-tag-version
+      - run: npm run build
+      - name: Publish
+        id: publish
+        # --tag is mandatory: npm publish defaults to `latest` even for a semver
+        # prerelease, which would point every plain `npm install` at a preview.
+        run: |
+          npm publish --tag preview
+          echo "published=true" >> "$GITHUB_OUTPUT"
+    outputs:
+      published: ${{ steps.publish.outputs.published }}
+      version: ${{ steps.preview.outputs.version }}
+      sha: ${{ steps.preview.outputs.sha }}
+
+  publish-tag-preview:
+    name: Tag the published preview
+    runs-on: ubuntu-latest
+    needs: publish-npm-preview
+    if: ${{ needs.publish-npm-preview.outputs.published == 'true' }}
+    environment: release
+    permissions:
+      contents: write # create refs/tags/v<version>
+    timeout-minutes: 5
+    steps:
+      # A re-run carries over the outputs of jobs it did not re-run. If that ever stops
+      # holding, fail with the manual recipe rather than tagging the wrong commit.
+      - name: Check the publish handed over a version and a commit
+        env:
+          VERSION: ${{ needs.publish-npm-preview.outputs.version }}
+          SHA: ${{ needs.publish-npm-preview.outputs.sha }}
+        run: |
+          if [ -z "$VERSION" ] || [ -z "$SHA" ]; then
+            echo "::error::publish-npm-preview reported version='$VERSION' sha='$SHA'." \
+              "Tag it by hand — see docs/RELEASES.md, 'A preview published but the" \
+              "commit was not tagged'."
+            exit 1
+          fi
+      - name: Create the tag
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          VERSION: ${{ needs.publish-npm-preview.outputs.version }}
+          SHA: ${{ needs.publish-npm-preview.outputs.sha }}
+        run: |
+          gh api "repos/$GITHUB_REPOSITORY/git/refs" \
+            -f ref="refs/tags/v$VERSION" \
+            -f sha="$SHA"
+          echo "Tagged \`v$VERSION\` at \`$SHA\`" >> "$GITHUB_STEP_SUMMARY"
 
   trigger-registry-update:
-    needs: publish-npm
+    needs: [publish-npm, publish-npm-preview]
+    # Both channels dispatch this: the registry has its own handling for preview
+    # versions. The two never fire together — a release merge publishes stable and
+    # skips the preview, and every other push does the reverse — so the registry sees
+    # exactly one dispatch per published version. The payload is deliberately
+    # unchanged: it names no version, and the registry resolves what it needs itself.
+    if: >-
+      ${{
+        always() && (
+          needs.publish-npm.result == 'success'
+          || needs.publish-npm-preview.outputs.published == 'true'
+          || (github.event_name == 'workflow_dispatch' && inputs.channel == 'stable' && !inputs.publish_npm)
+        )
+      }}
     runs-on: ubuntu-latest
     environment: release
     permissions: {}
+    # npm metadata is normally visible within about five minutes. Leave 2.5x that
+    # window for propagation, plus enough time to mint the token and dispatch.
+    timeout-minutes: 15
     steps:
+      - name: Wait for package to become available
+        if: ${{ needs.publish-npm.result == 'success' || needs.publish-npm-preview.outputs.published == 'true' }}
+        env:
+          PACKAGE: "@agentclientprotocol/claude-agent-acp"
+          VERSION: ${{ needs.publish-npm-preview.outputs.version || needs.publish-npm.outputs.version }}
+        #language=bash
+        run: |
+          if [ -z "$VERSION" ]; then
+            echo "::error::The publish job did not report a package version."
+            exit 1
+          fi
+
+          deadline=$((SECONDS + 750))
+          while (( SECONDS < deadline )); do
+            if timeout 10s npm pack "$PACKAGE@$VERSION" \
+              --dry-run \
+              --ignore-scripts \
+              --silent \
+              --registry=https://registry.npmjs.org \
+              --prefer-online \
+              --fetch-retries=0 >/dev/null 2>&1; then
+              echo "$PACKAGE@$VERSION is available from npm."
+              exit 0
+            fi
+
+            remaining=$((deadline - SECONDS))
+            if (( remaining > 0 )); then
+              echo "Waiting for $PACKAGE@$VERSION to become available (${remaining}s remaining)..."
+              sleep 10
+            fi
+          done
+
+          echo "::error::$PACKAGE@$VERSION was not available from npm after 12.5 minutes."
+          exit 1
+
       - name: Generate token scoped to the registry repo
         uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1
         id: registry-token

.prettierignore

@@ -5,3 +5,7 @@ dist
 .release-please-manifest.json
 release-please-config.json
 CHANGELOG.md
+
+# Recorded ACP traffic, written by src/tests/acp-scenarios.test.ts.
+src/tests/acp-scenarios/__snapshots__
+src/tests/acp-scenarios/origin-main

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "0.64.1"
+  ".": "0.84.0"
 }

AGENTS.md

@@ -0,0 +1,48 @@
+# Agent guide
+
+An ACP-compatible coding agent powered by the Claude Agent SDK. Source in `src/`,
+TypeScript, ESM, Node >= 22.
+
+## Commands
+
+```sh
+npm run build         # tsc
+npm run test:run      # vitest, single pass
+npm run check         # eslint + prettier --check
+npm run lint:fix      # eslint --fix
+npm run format        # prettier --write
+```
+
+CI runs `format:check`, `lint`, `build` and `test:run`. Run `npm run check` before
+opening a PR.
+
+## Pull requests
+
+Squash merges use the PR title as the commit subject, and release-please parses it
+to compute the next version. Titles must be conventional commits using one of:
+`feat`, `fix`, `perf`, `revert`, `docs`, `style`, `chore`, `refactor`, `test`,
+`build`, `ci`. `conventional-prs.yml` rejects anything else.
+
+The title also decides the release: `feat:` bumps the minor, `fix:`/`perf:` the
+patch, and `chore:`/`ci:`/`test:` and friends do not release at all.
+
+## Releasing
+
+Stable releases are fully automated by release-please. There is no manual release
+workflow, and the version is never chosen by hand — it follows from the commit
+history.
+
+```sh
+npm run release:preflight     # verifies it is safe to release, prints the PR and version
+gh pr merge <pr-number> --squash
+```
+
+The preflight is the guard-list as code; if it exits non-zero, follow what it
+prints rather than merging.
+
+Every _other_ push to `main` publishes a preview to npm — `0.73.1-preview.4` and
+so on — under the `preview` dist-tag, tags the commit it came from, and updates
+the agent registry the same way a release does. Only `latest` is reserved for
+real releases. So anything merged to `main` is published within minutes; there is
+no staging branch. Full runbook, including how to recover a stalled release:
+[`docs/RELEASES.md`](docs/RELEASES.md).

CHANGELOG.md

@@ -1,5 +1,273 @@
 # Changelog
 
+## [0.84.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.83.0...v0.84.0) (2026-09-28)
+
+
+### Features
+
+* **deps:** update Claude SDK ([#1189](https://github.com/agentclientprotocol/claude-agent-acp/issues/1189)) ([d5e6f33](https://github.com/agentclientprotocol/claude-agent-acp/commit/d5e6f33046614fca4798d49f0c77edba951a6771))
+
+## [0.83.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.82.0...v0.83.0) (2026-09-28)
+
+
+### Features
+
+* **deps:** Bump @anthropic-ai/claude-agent-sdk to 0.3.283 ([#1186](https://github.com/agentclientprotocol/claude-agent-acp/issues/1186)) ([49858b5](https://github.com/agentclientprotocol/claude-agent-acp/commit/49858b527397a08d343fe2c148a5fe9e3eb84547))
+
+## [0.82.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.81.2...v0.82.0) (2026-09-28)
+
+
+### Features
+
+* AIR tool call contract, exact git patches, plan file, and fixes for every client ([#1153](https://github.com/agentclientprotocol/claude-agent-acp/issues/1153)) ([875d75f](https://github.com/agentclientprotocol/claude-agent-acp/commit/875d75f2a4941d9c6313ed51f89da0f42443ac2f))
+
+
+### Bug Fixes
+
+* use ACP auth errors without access updates ([#1179](https://github.com/agentclientprotocol/claude-agent-acp/issues/1179)) ([e6681d2](https://github.com/agentclientprotocol/claude-agent-acp/commit/e6681d2a5734857727352474c8c9aa848f9210ee))
+
+## [0.81.2](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.81.1...v0.81.2) (2026-09-24)
+
+
+### Bug Fixes
+
+* announce resumed subagent generations when they start ([#1173](https://github.com/agentclientprotocol/claude-agent-acp/issues/1173)) ([b495e55](https://github.com/agentclientprotocol/claude-agent-acp/commit/b495e55a2249f066dab76e56316080f151df99be))
+* continue clear-context plans approved in a background followup ([#1170](https://github.com/agentclientprotocol/claude-agent-acp/issues/1170)) ([a2c362c](https://github.com/agentclientprotocol/claude-agent-acp/commit/a2c362c948511b203b43982f13ab068ba14741ea))
+
+## [0.81.1](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.81.0...v0.81.1) (2026-09-23)
+
+
+### Bug Fixes
+
+* gate login result text on error state ([#1103](https://github.com/agentclientprotocol/claude-agent-acp/issues/1103)) ([6e97e07](https://github.com/agentclientprotocol/claude-agent-acp/commit/6e97e071c581002b43d9556dbd1d1376ebf9516f))
+* honor permissions.disableBypassPermissionsMode ([#1165](https://github.com/agentclientprotocol/claude-agent-acp/issues/1165)) ([281e47e](https://github.com/agentclientprotocol/claude-agent-acp/commit/281e47eb810da748b9e66798086f0010dbb4dc4b))
+* include model on usage updates ([#1032](https://github.com/agentclientprotocol/claude-agent-acp/issues/1032)) ([da11f1f](https://github.com/agentclientprotocol/claude-agent-acp/commit/da11f1feb269b93f13fde7470f2b5a1b070867a9))
+* keep the agent starting when the managed-policy tier cannot be read ([#1146](https://github.com/agentclientprotocol/claude-agent-acp/issues/1146)) ([58c5db1](https://github.com/agentclientprotocol/claude-agent-acp/commit/58c5db1fdc1b6fbce27224523fddebd3c52a65dd))
+* mark informational chunks with metadata ([#1055](https://github.com/agentclientprotocol/claude-agent-acp/issues/1055)) ([bd059c1](https://github.com/agentclientprotocol/claude-agent-acp/commit/bd059c10e042c126933f27abd33f5523f39fab72))
+* offer bypass alongside auto in plan approval ([#1164](https://github.com/agentclientprotocol/claude-agent-acp/issues/1164)) ([43c27e9](https://github.com/agentclientprotocol/claude-agent-acp/commit/43c27e97aacd9b711aefcb4b84271bf872c2eea7))
+* preserve context usage when quota is exhausted ([#1132](https://github.com/agentclientprotocol/claude-agent-acp/issues/1132)) ([39062b6](https://github.com/agentclientprotocol/claude-agent-acp/commit/39062b63ff3087fc7ce2655a9738450f5f61682c))
+* preserve native Vertex endpoint defaults ([#1104](https://github.com/agentclientprotocol/claude-agent-acp/issues/1104)) ([29a4e98](https://github.com/agentclientprotocol/claude-agent-acp/commit/29a4e9847761837ab85ea42d4bab9267be606755))
+* publish effective mode after plan approval ([#1163](https://github.com/agentclientprotocol/claude-agent-acp/issues/1163)) ([a2f4239](https://github.com/agentclientprotocol/claude-agent-acp/commit/a2f4239543b22d0928fbdbef7a9c7a4854b3d61d))
+* recreate resumed sessions when any session option changes ([#1097](https://github.com/agentclientprotocol/claude-agent-acp/issues/1097)) ([df38ccc](https://github.com/agentclientprotocol/claude-agent-acp/commit/df38cccae04ce4abb525447c5e8d9db78ffec61c))
+* render Write tool calls that use path/file_text aliases ([#1161](https://github.com/agentclientprotocol/claude-agent-acp/issues/1161)) ([90cde4b](https://github.com/agentclientprotocol/claude-agent-acp/commit/90cde4b3974656794fbb274ac6ad8e57f701e618))
+* replay marker-only slash skill prompts ([#1035](https://github.com/agentclientprotocol/claude-agent-acp/issues/1035)) ([97394d9](https://github.com/agentclientprotocol/claude-agent-acp/commit/97394d93b695c141eda71b85025bc4e22141b8c4))
+* **session:** recreate query when configured skills change ([#968](https://github.com/agentclientprotocol/claude-agent-acp/issues/968)) ([388a0f5](https://github.com/agentclientprotocol/claude-agent-acp/commit/388a0f51914ef59f2168007b633927e1a9d6ec48)), closes [#955](https://github.com/agentclientprotocol/claude-agent-acp/issues/955)
+* settle steered turns on the result that answers the steer ([#1166](https://github.com/agentclientprotocol/claude-agent-acp/issues/1166)) ([9392c69](https://github.com/agentclientprotocol/claude-agent-acp/commit/9392c69cc66591ade56a08200d807577180aa682))
+
+## [0.81.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.80.0...v0.81.0) (2026-09-22)
+
+
+### Features
+
+* **deps:** update Claude SDK ([#1157](https://github.com/agentclientprotocol/claude-agent-acp/issues/1157)) ([eb989e9](https://github.com/agentclientprotocol/claude-agent-acp/commit/eb989e93f4e20315a85405ef099f97eec899df13))
+* Send experimental session notices for live advisories ([#1155](https://github.com/agentclientprotocol/claude-agent-acp/issues/1155)) ([79851b8](https://github.com/agentclientprotocol/claude-agent-acp/commit/79851b86685b8a0673dec54d85d6fa2a3b749cfb))
+
+## [0.80.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.79.0...v0.80.0) (2026-09-22)
+
+
+### Features
+
+* **deps:** Bump claude-agent-sdk to 0.3.278 ([#1147](https://github.com/agentclientprotocol/claude-agent-acp/issues/1147)) ([5bc3b4e](https://github.com/agentclientprotocol/claude-agent-acp/commit/5bc3b4e5609c7e4290fa1bca50c30c7340de6bbf))
+
+
+### Bug Fixes
+
+* close interrupted compaction lifecycles ([#1154](https://github.com/agentclientprotocol/claude-agent-acp/issues/1154)) ([a05aca6](https://github.com/agentclientprotocol/claude-agent-acp/commit/a05aca6b81bfd172ab47064dd21e835da95fc72b))
+* prefer terminal output deltas ([#1150](https://github.com/agentclientprotocol/claude-agent-acp/issues/1150)) ([c6f9668](https://github.com/agentclientprotocol/claude-agent-acp/commit/c6f9668c1234b43888bc44aaf63daf8be1a745e2))
+
+## [0.79.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.78.0...v0.79.0) (2026-09-17)
+
+
+### Features
+
+* Update to claude agent sdk 0.3.274 ([#1143](https://github.com/agentclientprotocol/claude-agent-acp/issues/1143)) ([d0fa8e0](https://github.com/agentclientprotocol/claude-agent-acp/commit/d0fa8e03853c4f5a9b074fc2af32931ffe6f588f))
+
+
+### Bug Fixes
+
+* show shell commands in permission prompts ([#1070](https://github.com/agentclientprotocol/claude-agent-acp/issues/1070)) ([bbae5c2](https://github.com/agentclientprotocol/claude-agent-acp/commit/bbae5c2c0936554104b07630b142fd71fe1d839e))
+
+## [0.78.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.77.0...v0.78.0) (2026-09-15)
+
+
+### Features
+
+* Add experimental ACP compaction update support ([#1134](https://github.com/agentclientprotocol/claude-agent-acp/issues/1134)) ([543a9a2](https://github.com/agentclientprotocol/claude-agent-acp/commit/543a9a2f97429659bb28d09691a71e4c99e41ed5))
+
+
+### Bug Fixes
+
+* keep the picked option when AskUserQuestion custom text is also supplied ([#1131](https://github.com/agentclientprotocol/claude-agent-acp/issues/1131)) ([8823ea6](https://github.com/agentclientprotocol/claude-agent-acp/commit/8823ea6fcb6743d37c1aad91ccd44725164b8927))
+
+
+### Performance Improvements
+
+* report file changes from Claude checkpoints ([#1138](https://github.com/agentclientprotocol/claude-agent-acp/issues/1138)) ([91f1699](https://github.com/agentclientprotocol/claude-agent-acp/commit/91f1699366ee98f9b3e9a6b96f0662c40b6ee38e))
+* supply AIR diff counts from Claude structured patches ([#1122](https://github.com/agentclientprotocol/claude-agent-acp/issues/1122)) ([735950a](https://github.com/agentclientprotocol/claude-agent-acp/commit/735950a83ee1fa25366515a3239482183a051dca))
+
+## [0.77.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.76.0...v0.77.0) (2026-09-14)
+
+
+### ⚠ BREAKING CHANGES
+
+* claudeCode.options.agent is no longer forwarded to Claude Code, and the agent-picker exports DEFAULT_AGENT_ID, AGENT_CONFIG_ID, BUILTIN_AGENT_NAMES, and discoverCustomAgents are removed. Consumers relying on main-thread agent selection must stop passing that option.
+
+### Features
+
+* Add tool names to tool calls ([#1128](https://github.com/agentclientprotocol/claude-agent-acp/issues/1128)) ([67c7c9b](https://github.com/agentclientprotocol/claude-agent-acp/commit/67c7c9b117af7464fd5d583f719bf6214a5508a8))
+* **deps:** Bump @anthropic-ai/claude-agent-sdk to 0.3.270 ([#1123](https://github.com/agentclientprotocol/claude-agent-acp/issues/1123)) ([d3205ab](https://github.com/agentclientprotocol/claude-agent-acp/commit/d3205ab11f873f58e50dddbf13f6d7c555a9f478))
+
+
+### Bug Fixes
+
+* keep multi-select answers when a custom answer is typed ([#1031](https://github.com/agentclientprotocol/claude-agent-acp/issues/1031)) ([1a4512c](https://github.com/agentclientprotocol/claude-agent-acp/commit/1a4512c71199709f6c59bd56c2c67aba63fe243d))
+* parse TaskList output without ambiguous regex ([#1006](https://github.com/agentclientprotocol/claude-agent-acp/issues/1006)) ([b274923](https://github.com/agentclientprotocol/claude-agent-acp/commit/b274923ef84a5a39b4ab3d12b3d10a8fa23f51f6))
+* strip injected system reminders from replayed prompts ([#1040](https://github.com/agentclientprotocol/claude-agent-acp/issues/1040)) ([15ba608](https://github.com/agentclientprotocol/claude-agent-acp/commit/15ba608a79b2cdfdb94c04ce1ebe03cfdae2fb51))
+
+
+### Code Refactoring
+
+* remove agent config option ([#1112](https://github.com/agentclientprotocol/claude-agent-acp/issues/1112)) ([6b7473b](https://github.com/agentclientprotocol/claude-agent-acp/commit/6b7473b1afb48fbf0cb3b463d576a89a73ddf7a3))
+
+## [0.76.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.75.1...v0.76.0) (2026-09-09)
+
+
+### Features
+
+* advertise recommended config values ([#1111](https://github.com/agentclientprotocol/claude-agent-acp/issues/1111)) ([2b666c3](https://github.com/agentclientprotocol/claude-agent-acp/commit/2b666c3d35566c60edafc5050d23cf2ce7ea1e95))
+* **deps-dev:** Bump vitest from 4.1.11 to 5.0.0 ([#1099](https://github.com/agentclientprotocol/claude-agent-acp/issues/1099)) ([194e195](https://github.com/agentclientprotocol/claude-agent-acp/commit/194e195b057497311558fea2a5fbd1b4953ea29d))
+* **deps:** Bump fast-uri from 3.1.6 to 3.1.7 ([#1100](https://github.com/agentclientprotocol/claude-agent-acp/issues/1100)) ([d870ebd](https://github.com/agentclientprotocol/claude-agent-acp/commit/d870ebd2fd14bda95f81ec4b86d76ef4ae258005))
+
+## [0.75.1](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.75.0...v0.75.1) (2026-09-05)
+
+
+### Bug Fixes
+
+* restore session forks and speed up loading ([#1089](https://github.com/agentclientprotocol/claude-agent-acp/issues/1089)) ([f5e79f5](https://github.com/agentclientprotocol/claude-agent-acp/commit/f5e79f55f8ba8d1cd0a72cbc78bfea726bea2f00))
+
+## [0.75.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.74.0...v0.75.0) (2026-09-05)
+
+
+### Features
+
+* **auth:** report the agent's auth identity over ACP (authStatus extension) ([#1080](https://github.com/agentclientprotocol/claude-agent-acp/issues/1080)) ([eb5ca9f](https://github.com/agentclientprotocol/claude-agent-acp/commit/eb5ca9fd17b6af4a4566be4ad75b64588ce60b52))
+* render usage statistics as Markdown ([#1085](https://github.com/agentclientprotocol/claude-agent-acp/issues/1085)) ([2081767](https://github.com/agentclientprotocol/claude-agent-acp/commit/20817678f68083a2997d1bc45ef20241a9097220))
+* surface context compaction as an ACP tool lifecycle ([#991](https://github.com/agentclientprotocol/claude-agent-acp/issues/991)) ([f74a517](https://github.com/agentclientprotocol/claude-agent-acp/commit/f74a51758dc42896addbcdaf7611a29ec1d1db17))
+
+## [0.74.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.73.0...v0.74.0) (2026-09-04)
+
+
+### Features
+
+* **auth:** refuse claude.ai subscriptions under `--hide-claude-auth` ([#1079](https://github.com/agentclientprotocol/claude-agent-acp/issues/1079)) ([da9f7e5](https://github.com/agentclientprotocol/claude-agent-acp/commit/da9f7e56956c770bd1339151d6166a011fe39174))
+
+## [0.73.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.72.0...v0.73.0) (2026-09-01)
+
+
+### Features
+
+* **deps:** update Claude SDK ([#1066](https://github.com/agentclientprotocol/claude-agent-acp/issues/1066)) ([b4e3aaa](https://github.com/agentclientprotocol/claude-agent-acp/commit/b4e3aaa727821a85cef6dcf51452381d35fd68a5))
+
+## [0.72.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.71.0...v0.72.0) (2026-09-01)
+
+
+### Features
+
+* **deps:** Update to @anthropic-ai/claude-agent-sdk 0.3.252  ([#1062](https://github.com/agentclientprotocol/claude-agent-acp/issues/1062)) ([9aaf066](https://github.com/agentclientprotocol/claude-agent-acp/commit/9aaf0663bf48a4209e8e6511af395102c05e501e))
+
+
+### Bug Fixes
+
+* Adopt per-model effort settings and user_message_uuid result attribution ([#1065](https://github.com/agentclientprotocol/claude-agent-acp/issues/1065)) ([a04d354](https://github.com/agentclientprotocol/claude-agent-acp/commit/a04d35496c1f1b4c19d8f4204ee6377de45624ab))
+
+## [0.71.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.70.0...v0.71.0) (2026-08-31)
+
+
+### Features
+
+* add ai generated session title ([#984](https://github.com/agentclientprotocol/claude-agent-acp/issues/984)) ([d334766](https://github.com/agentclientprotocol/claude-agent-acp/commit/d334766ef95dd89201979d42252e3d2a5a259cb9))
+* align Claude modes and clear-context planning ([#1004](https://github.com/agentclientprotocol/claude-agent-acp/issues/1004)) ([996d488](https://github.com/agentclientprotocol/claude-agent-acp/commit/996d488589b8db7a0f9af3dfc7b886d9d47ebae9))
+* **deps:** Bump @anthropic-ai/claude-agent-sdk to 0.3.238 ([#1018](https://github.com/agentclientprotocol/claude-agent-acp/issues/1018)) ([ee9f300](https://github.com/agentclientprotocol/claude-agent-acp/commit/ee9f300db4562e8b7958cec9fa63dab05a5c2eb0))
+* expose native subagents and async tasks ([#1017](https://github.com/agentclientprotocol/claude-agent-acp/issues/1017)) ([14d192d](https://github.com/agentclientprotocol/claude-agent-acp/commit/14d192d1087ea8662392b5c61c9fcdd496c5a179))
+* expose permission mode kinds ([#1025](https://github.com/agentclientprotocol/claude-agent-acp/issues/1025)) ([caf609b](https://github.com/agentclientprotocol/claude-agent-acp/commit/caf609b56c91f677ffe82b6e9d11d9e9dfd99d45))
+* report per-model token usage on prompt responses ([#1037](https://github.com/agentclientprotocol/claude-agent-acp/issues/1037)) ([fad4d10](https://github.com/agentclientprotocol/claude-agent-acp/commit/fad4d10e46c5e65fc6d426c98074bbb76067bf25))
+* support message-specific ACP session forks ([#1046](https://github.com/agentclientprotocol/claude-agent-acp/issues/1046)) ([c3ff343](https://github.com/agentclientprotocol/claude-agent-acp/commit/c3ff3438844f5249d6a7f5c297906e2cd3d5fa7f))
+
+
+### Bug Fixes
+
+* change min zod version to 4.x to avoid failing directory imports on 'v4' ([#1057](https://github.com/agentclientprotocol/claude-agent-acp/issues/1057)) ([7c66108](https://github.com/agentclientprotocol/claude-agent-acp/commit/7c6610835f26f18cd162b78dff74a7b7cd74497a))
+* defer steering while user input is pending ([#1045](https://github.com/agentclientprotocol/claude-agent-acp/issues/1045)) ([8710ce1](https://github.com/agentclientprotocol/claude-agent-acp/commit/8710ce1cbccf562cb04b4bcc30e053e960aee05f))
+
+## [0.70.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.69.0...v0.70.0) (2026-08-17)
+
+
+### Features
+
+* switch providers for loaded Claude sessions ([#1002](https://github.com/agentclientprotocol/claude-agent-acp/issues/1002)) ([50a9543](https://github.com/agentclientprotocol/claude-agent-acp/commit/50a95434e94318456f2d07c3d21aaf3595c3407d))
+
+## [0.69.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.68.0...v0.69.0) (2026-08-16)
+
+
+### Features
+
+* report changed files to AIR ([#1001](https://github.com/agentclientprotocol/claude-agent-acp/issues/1001)) ([450d6b1](https://github.com/agentclientprotocol/claude-agent-acp/commit/450d6b19dc46a041128356a6fa3cfa3ce6a5a382))
+
+## [0.68.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.67.0...v0.68.0) (2026-08-14)
+
+
+### Features
+
+* align typed session failures with AIR protocol ([#992](https://github.com/agentclientprotocol/claude-agent-acp/issues/992)) ([0581b9c](https://github.com/agentclientprotocol/claude-agent-acp/commit/0581b9cf397ffd88f2830db721c2d8e3689045e4))
+
+## [0.67.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.66.0...v0.67.0) (2026-08-14)
+
+
+### Features
+
+* **deps:** Update to @anthropic-ai/claude-agent-sdk v0.3.232 ([#993](https://github.com/agentclientprotocol/claude-agent-acp/issues/993)) ([de0d0e2](https://github.com/agentclientprotocol/claude-agent-acp/commit/de0d0e2b7d185c521c3d1ac7b86e4312c919abfe))
+* expose typed session failures for AIR ([#979](https://github.com/agentclientprotocol/claude-agent-acp/issues/979)) ([8157ee1](https://github.com/agentclientprotocol/claude-agent-acp/commit/8157ee113e705750be4eb6cc787bdd12f1db84ff))
+* publish the model fallback as a warning advisory ([#990](https://github.com/agentclientprotocol/claude-agent-acp/issues/990)) ([35aaddb](https://github.com/agentclientprotocol/claude-agent-acp/commit/35aaddb3d5b14eca316582ab285af8a660150dae))
+* surface resolved model name in default model option description ([#982](https://github.com/agentclientprotocol/claude-agent-acp/issues/982)) ([ec73cd8](https://github.com/agentclientprotocol/claude-agent-acp/commit/ec73cd8560be7d5e8b9741e404d7d45e17336996))
+* surface Skill tool calls with name and kind in _meta ([#986](https://github.com/agentclientprotocol/claude-agent-acp/issues/986)) ([1f09e9a](https://github.com/agentclientprotocol/claude-agent-acp/commit/1f09e9a3cae787b0effdfae0e7205ef7fe22b9dc))
+
+
+### Bug Fixes
+
+* preserve task plans across prompts ([#974](https://github.com/agentclientprotocol/claude-agent-acp/issues/974)) ([1afa940](https://github.com/agentclientprotocol/claude-agent-acp/commit/1afa940a2c8c0f4c610f4f64d30c0961642907b0))
+* show a pending title while Claude prepares a file ([#978](https://github.com/agentclientprotocol/claude-agent-acp/issues/978)) ([3df1ede](https://github.com/agentclientprotocol/claude-agent-acp/commit/3df1ede89f217312bc237124dc1eccc10c860f99))
+
+## [0.66.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.65.0...v0.66.0) (2026-08-07)
+
+
+### Features
+
+* **deps-dev:** Bump globals from 17.8.0 to 17.9.0 in the minor group ([#960](https://github.com/agentclientprotocol/claude-agent-acp/issues/960)) ([7f27c47](https://github.com/agentclientprotocol/claude-agent-acp/commit/7f27c47c5c7c49e65014e9f7dc55cba17352d33b))
+* expose provider-neutral ACP goal extension ([#964](https://github.com/agentclientprotocol/claude-agent-acp/issues/964)) ([8b31dea](https://github.com/agentclientprotocol/claude-agent-acp/commit/8b31dea11bed54f86c41217759159c415611346c))
+
+
+### Bug Fixes
+
+* publish and replace Claude goals reliably ([#967](https://github.com/agentclientprotocol/claude-agent-acp/issues/967)) ([f8fd3ab](https://github.com/agentclientprotocol/claude-agent-acp/commit/f8fd3ab8224420f8ced570e974cde09612939d6b))
+
+## [0.65.0](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.64.2...v0.65.0) (2026-08-05)
+
+
+### Features
+
+* **deps-dev:** Bump nanoid from 3.3.16 to 3.3.17 ([#951](https://github.com/agentclientprotocol/claude-agent-acp/issues/951)) ([b965dd2](https://github.com/agentclientprotocol/claude-agent-acp/commit/b965dd21917e822b56f5012c3572902f26c065c9))
+* **deps-dev:** Bump tinyexec from 1.2.4 to 1.3.0 in the minor group ([#959](https://github.com/agentclientprotocol/claude-agent-acp/issues/959)) ([15b4eb4](https://github.com/agentclientprotocol/claude-agent-acp/commit/15b4eb46f329566837eae58f2ee4b05e3e81bf64))
+* **deps:** Bump @hono/node-server from 1.19.17 to 2.1.0 ([#956](https://github.com/agentclientprotocol/claude-agent-acp/issues/956)) ([f9123f3](https://github.com/agentclientprotocol/claude-agent-acp/commit/f9123f3e18560b580398aabf49e2190f69746976))
+* **deps:** Bump fast-uri from 3.1.4 to 3.1.5 ([#952](https://github.com/agentclientprotocol/claude-agent-acp/issues/952)) ([0988438](https://github.com/agentclientprotocol/claude-agent-acp/commit/098843842895dcb450746bd064dbb1509e3049d1))
+* **steering:** settle a steered turn at idle, not at the interrupt ([#958](https://github.com/agentclientprotocol/claude-agent-acp/issues/958)) ([a84b810](https://github.com/agentclientprotocol/claude-agent-acp/commit/a84b81080a4127edf40bc448fc8bf2b15503304d))
+
+## [0.64.2](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.64.1...v0.64.2) (2026-08-02)
+
+
+### Bug Fixes
+
+* restore the single-tool representation for ExitPlanMode ([#942](https://github.com/agentclientprotocol/claude-agent-acp/issues/942)) ([4302a4b](https://github.com/agentclientprotocol/claude-agent-acp/commit/4302a4b0b6df821b164cbe4857f26cf5b44b532c))
+
 ## [0.64.1](https://github.com/agentclientprotocol/claude-agent-acp/compare/v0.64.0...v0.64.1) (2026-08-02)
 
 

CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md

README.md

@@ -9,6 +9,7 @@ This tool implements an ACP agent by using the official [Claude Agent SDK](https
 - Context @-mentions
 - Images
 - Tool calls (with permission requests)
+- Compact file changes through the negotiated [AIR diff patch extension](docs/air-extensions.md#diff-patch)
 - Following
 - Edit review
 - TODO lists
@@ -16,19 +17,33 @@ This tool implements an ACP agent by using the official [Claude Agent SDK](https
 - Interactive (and background) terminals
 - Custom [Slash commands](https://docs.anthropic.com/en/docs/claude-code/slash-commands)
 - Client MCP servers
+- Session-scoped long-running goals for AIR through the [goal extension](docs/air-extensions.md#goal) under `_meta.jetbrains.air.goal`
+- Structured errors, recovery, and warnings through the opt-in [session failure extension](docs/air-extensions.md#session-failure)
+- Concrete model and effort defaults through the opt-in [recommended config value extension](docs/air-extensions.md#recommended-config-values)
+- Tool permission presentation, editable choices, and durable effects through the [permission extension](docs/air-extensions.md#permission-presentation)
+- One fact per field in every tool call report, as the [ACP tool call contract](docs/air-extensions.md#tool-call-contract) defines
+- All AIR extensions, capabilities, and `_meta` keys: [AIR extensions](docs/air-extensions.md)
 
 Learn more about the [Agent Client Protocol](https://agentclientprotocol.com/).
 
-### Nested subagent transcripts
+To try changes that have landed on `main` but are not released yet, install from the
+`preview` channel — every push to `main` publishes one. See
+[`docs/RELEASES.md`](docs/RELEASES.md#preview-releases).
 
-ACP 1.2 has no standard subagent tool kind or nested-message relationship. Clients that can render
-nested transcripts can opt in with `clientCapabilities._meta["subagent-transcript"] = true`.
-The agent then forwards subagent text, thinking, and tool calls, relating nested updates to the
-launching Agent/Task call through `_meta.claudeCode.parentToolUseId`. Agent/Task calls are marked
-with `_meta.claudeCode.subagent = true`.
+```sh
+npm install @agentclientprotocol/claude-agent-acp@preview
+```
 
-Clients that do not advertise the capability retain the legacy flattened behavior. In both modes,
-the normal Agent/Task tool result is preserved as the protocol-compatible fallback.
+### Subagent sessions
+
+Subagents are exposed only after bilateral capability negotiation. Until the released ACP SDKs
+preserve the draft `clientCapabilities.subagents` field, a supporting client may advertise
+`nativeSubagentSessions` in `_meta.jetbrains.air.capabilities`; the adapter mirrors the capability
+in its initialize response. The canonical field remains supported and takes precedence once it is
+available. Without either client signal, Agent/Task lifecycle keeps its legacy ordinary ACP
+tool-call representation and child interactions stay on the root session. Clients that use the
+historical `_meta["subagent-transcript"]` capability or `forwardSubagentText` session option retain
+the flattened child transcript behavior. See [AIR extensions](docs/air-extensions.md#native-subagent-sessions).
 
 ## Contribution Policy
 

docs/RELEASES.md

@@ -1,24 +1,245 @@
-## How to publish a new release
+# Releases
 
-1. Create a new branch prep-vX.X.X
+Releases are automated by [release-please](https://github.com/googleapis/release-please)
+in [`.github/workflows/publish.yml`](../.github/workflows/publish.yml). Every push
+to `main` re-computes the next version from the conventional commit messages and
+keeps a single release PR open, titled `chore(main): release X.Y.Z` and labelled
+`autorelease: pending`.
+
+Merging that PR is what releases. It tags `vX.Y.Z`, creates the GitHub release,
+publishes to npm, and dispatches a version update to the agent registry.
+
+There is no manual release button, and versions are never typed in by hand: the
+version is an output of the commit history, not an input.
+
+Every _other_ push to `main` publishes a preview instead — see
+[Preview releases](#preview-releases). Anything merged to `main` is on npm within
+minutes; there is no staging branch.
+
+## Releasing
 
 ```sh
-git checkout -b prep-vX.X.X
+npm run release:preflight
 ```
 
-2. Bump the version in package.json
+This reports the open release PR, the version it will ship, and checks that the
+repository is in a state where merging is safe. Nothing has to be remembered —
+if it exits non-zero, follow what it prints instead of merging.
+
+Then merge it, using the PR number the preflight printed:
 
 ```sh
-npm version vX.X.X
+gh pr merge <pr-number> --squash
+gh run watch "$(gh run list --workflow=publish.yml --limit 1 --json databaseId --jq '.[0].databaseId')"
 ```
 
-3. Add a new entry in CHANGELOG.md
-4. Create a PR for `prev-vX.X.X` & merge it
-5. Create tag and push it
+The run is looked up rather than picked interactively, so this is safe to script.
+If the workflow has already finished, `gh run list --workflow=publish.yml` shows
+the outcome instead.
+
+Merging main requires no review, so a green preflight and `Build` are the only
+gates. Once the workflow finishes, confirm both outputs landed:
 
 ```sh
-git tag vX.X.X
-git push origin vX.X.X
+gh release view "v<version>"
+npm view "@agentclientprotocol/claude-agent-acp@<version>"
 ```
 
-6. Paste CHANGELOG into release notes and publish the version on GitHub
+## Preview releases
+
+Every push to `main` that is not a release merge publishes a preview from the
+same workflow. There is no GitHub release — only an npm publish under the
+`preview` dist-tag, a `v<version>` tag on the commit it came from, and the same
+agent registry update a stable release dispatches, since the registry has its own
+handling for preview versions.
+
+Those are three jobs, in that order: `publish-npm-preview` mirrors `publish-npm`
+and does nothing but publish; `publish-tag-preview` creates the tag; and
+`trigger-registry-update` is shared with the stable path. Before dispatching,
+the registry job polls npm for the exact published version for up to 12.5 minutes,
+including downloading its tarball, so the registry never checks while npm is
+still propagating the package. The tag is a separate job so that a tag failure
+can be retried on its own with **Re-run failed jobs** — re-running the publish is
+not an option, because npm versions are immutable and publishing the same one
+twice fails outright.
+
+Both downstream jobs are gated on a `published` output that the publish step
+sets only after `npm publish --tag preview` succeeds. This ensures tagging runs
+only after publication and the registry update runs only after that exact version
+can also be downloaded from npm.
+
+A stable and a preview dispatch can never collide — a release merge publishes
+stable and skips the preview, every other push does the reverse — so the registry
+sees exactly one dispatch per published version.
+
+```sh
+npm install @agentclientprotocol/claude-agent-acp@preview
+npm view @agentclientprotocol/claude-agent-acp dist-tags
+git ls-remote --tags origin 'refs/tags/*preview*'
+```
+
+The version is the `package.json` version with the patch incremented, plus
+`-preview.N`: with `main` at 0.73.0 the previews are `0.73.1-preview.1`,
+`0.73.1-preview.2`, and so on. `N` restarts at 1 whenever release-please moves
+`package.json`, which keeps the sequence monotonic whichever way the next release
+goes — a patch release makes the next base 0.73.2, a minor makes it 0.74.1, and
+both sort above every `0.73.1-preview.*`.
+
+`0.73.1-preview.4` is **not** a promise that 0.73.1 will ship. The base is a
+patch bump because that is the only choice depending solely on `package.json`,
+which release-please only ever increases. Using release-please's predicted next
+version would read better but that prediction moves mid-flight: a `fix:` opens a
+0.73.1 release PR, a later `feat:` moves it to 0.74.0, and `N` would reset under
+previews that were already published.
+
+`N` comes from [`scripts/next-preview-version.mjs`](../scripts/next-preview-version.mjs),
+which takes the larger of two sources. The npm registry says what is taken — npm
+versions are immutable and stay reserved even after `npm unpublish`, so reusing
+one is a hard failure — but it is CDN-served and can lag a publish by minutes.
+The git tags this job writes are strongly consistent and cover that window. The
+job publishes before it tags, so a version can exist on npm without a tag but
+never the reverse; that is why a registry read failure aborts the run rather than
+falling back to the tags alone.
+
+Two pushes landing together cannot collide, because the job takes a concurrency
+group. GitHub keeps only one run pending per group, so a third push arriving
+while one preview runs and another waits drops the waiting one — that commit
+simply gets no preview.
+
+`latest` stays put because the job passes `npm publish --tag preview`. Without
+it npm would move `latest` onto the preview: `--tag` defaults to `latest` even
+for a semver prerelease. Right after a release the `preview` dist-tag can name a
+version _below_ `latest` until the next push lands; that is cosmetic.
+
+Release merges are excluded by checking the head commit's author and the subject
+release-please generates. Both are checked, either is enough, and the cost of a
+miss is one wasted version number plus a `preview` tag briefly pointing at
+already-released code — `latest` is untouched. Previews start directly on pushes
+to `main`, without waiting for CI or the `release-please` job. The commit checks
+let previews run independently of release-please's outputs.
+
+To publish a preview by hand from any commit:
+
+```sh
+gh workflow run publish.yml --ref main \
+  -f channel=preview -f ref=<commit-or-branch> -f publish_npm=false
+```
+
+`--ref main` is required: the `release` environment only accepts protected
+branches, so a dispatch from anywhere else is rejected before the job starts.
+
+## How the version is chosen
+
+Squash merges use the PR title as the commit subject, so the PR title decides the
+next version. [`conventional-prs.yml`](../.github/workflows/conventional-prs.yml)
+rejects titles release-please would not understand.
+
+| PR title prefix                                           | Effect                      |
+| --------------------------------------------------------- | --------------------------- |
+| `fix:`, `perf:`, `revert:`, `docs:`                       | patch, e.g. 0.66.0 → 0.66.1 |
+| `feat:`                                                   | minor, e.g. 0.66.0 → 0.67.0 |
+| any of the above with `!`, or BREAKING CHANGE             | minor while below 1.0.0     |
+| `chore:`, `ci:`, `build:`, `test:`, `refactor:`, `style:` | no release on their own     |
+
+Breaking changes bump the minor rather than the major because
+`bump-minor-pre-major` is set in
+[`release-please-config.json`](../release-please-config.json) and the package is
+still below 1.0.0. That is deliberate: it keeps a single `!` in a PR title from
+shipping 1.0.0 by accident.
+
+Note that `config-file` only takes effect while the workflow does **not** pass a
+`release-type` input to the action — with `release-type` set, the action ignores
+the config entirely. The release type is declared inside the config instead.
+
+`release-type` also switches release-please from `Manifest.fromManifest` to
+`Manifest.fromConfig`, which is a second and sharper reason never to set it. On
+the manifest path the previous release is found by an exact string match against
+the version in [`.release-please-manifest.json`](../.release-please-manifest.json),
+which is why the `v<x>-preview.<n>` tags are invisible to it. On the config path
+release-please instead sorts every candidate tag and release descending and takes
+the highest — and there the preview tags _would_ be candidates.
+
+Because the config is what is read, it also has to say
+`"include-component-in-tag": false`. Left at its default, release-please derives a
+component from the package name and tags `claude-agent-acp-vX.Y.Z` instead of
+`vX.Y.Z`. That renames the tag every step here looks up, and because no tag under
+the new scheme exists, it also walks the entire commit history into the changelog
+rather than just what landed since the last release. The preflight checks the tag
+release-please is going to use, so this cannot reach a published release.
+
+Releasing 1.0.0 is therefore an explicit act: add `"release-as": "1.0.0"` to
+`release-please-config.json` in its own PR, release, then remove it again.
+
+## Recovering a stalled release
+
+### The release PR merged but nothing was tagged
+
+The preflight fails with `release-please is jammed`. While a merged release PR
+still carries `autorelease: pending`, release-please refuses to open any new
+release PR at all, so every later release stalls silently until this is cleared.
+
+Take the release notes release-please already wrote into the changelog, create
+the missing release, then move the label the way release-please would have:
+
+```sh
+awk '/^## \[<version>\]/{f=1;print;next} /^## \[/{f=0} f' CHANGELOG.md > notes.md
+gh release create "v<version>" --target <merge-commit-sha> --notes-file notes.md
+gh pr edit <pr-number> --remove-label "autorelease: pending" \
+  --add-label "autorelease: tagged"
+```
+
+Then publish the tag as described below.
+
+### The tag exists but npm or the registry is missing
+
+npm publishes through OIDC from inside the workflow, so this cannot be done from
+a laptop. Re-run the publish workflow against the existing tag:
+
+```sh
+gh workflow run publish.yml -f ref="v<version>" -f publish_npm=true
+```
+
+npm versions are immutable. If the package already published and only the
+registry update failed, pass `-f publish_npm=false` so the run skips publishing
+and only re-dispatches the registry update.
+
+### A preview published but the commit was not tagged
+
+Only the publish is irreversible, so re-run just the tag job:
+
+```sh
+gh run rerun <run-id> --failed
+```
+
+Or **Re-run failed jobs** on the run in the web or mobile UI. This re-runs
+`publish-tag-preview` alone and leaves the successful publish untouched, which
+matters because re-publishing an immutable npm version would fail.
+
+If the re-run reports that it received no version or commit, the run's carried
+over job outputs are gone and it cannot tag anything safely. Do it by hand
+instead, taking the version from the publish job's log:
+
+```sh
+gh api "repos/$(gh repo view --json nameWithOwner --jq .nameWithOwner)/git/refs" \
+  -f ref="refs/tags/v<version>" -f sha="<commit-sha>"
+```
+
+Either way nothing is broken in the meantime: the next preview still picks the
+right `N` once the registry CDN catches up. The tag is how that number is known
+immediately.
+
+## Credentials
+
+| Secret                                                        | Used for                                                          |
+| ------------------------------------------------------------- | ----------------------------------------------------------------- |
+| `RELEASE_PLZ_APP_ID`, `RELEASE_PLZ_APP_PRIVATE_KEY`           | App token for release PRs and tags, so they can trigger workflows |
+| `REGISTRY_UPDATER_APP_ID`, `REGISTRY_UPDATER_APP_PRIVATE_KEY` | App token scoped to the `registry` repository                     |
+
+Publishing to npm uses OIDC trusted publishing, so there is no npm token. All
+release jobs run in the `release` environment.
+
+npm binds a trusted publisher to one repository, one **workflow filename** and
+one environment, and a package may only have one such binding. That is why
+preview publishing is another job inside `publish.yml` rather than a workflow of
+its own: a separate file would fail to authenticate, and registering it would
+cost the stable path its publisher.

examples/simple-client.ts

@@ -0,0 +1,706 @@
+/**
+ * Example: a dead-simple interactive ACP client for this agent.
+ *
+ * This is the "no editor required" way to exercise the agent: it launches
+ * `dist/index.js` as a subprocess, speaks ACP over its stdio using the SDK, and
+ * prints every JSON-RPC message that crosses the wire in both directions. Each
+ * line you type becomes a `session/prompt`; the agent's answer streams back as
+ * `session/update` notifications.
+ *
+ * Every message is preceded by a header line naming its direction:
+ *
+ *   [agent] ◂   inbound  — everything the agent sends us
+ *   [user]  ▸   outbound — everything we send the agent, including our own
+ *                          permission answers and `session/cancel`
+ *
+ * The label and the arrow carry the direction, so it survives NO_COLOR and
+ * redirection to a file (`2> wire.log`). The JSON itself is printed in full,
+ * flush left and undecorated — select it and you have valid JSON on the
+ * clipboard. This exists to show you the protocol, not to summarize it.
+ *
+ * There are four ways for a client to get a message to this agent, and all four
+ * are reachable from the prompt so you can watch what each one looks like on
+ * the wire. Plain text is the first; the rest are `!`-prefixed commands, chosen
+ * so they cannot be confused with the agent's own slash commands (`/compact`
+ * and friends are ordinary prompt text here). `!!` escapes a literal `!`.
+ *
+ *   <text>          `session/prompt`. Typed mid-turn it is *buffered* by this
+ *                   client and sent once the running turn responds.
+ *   !steer <text>   `_session/steering` — injected into the turn that is
+ *                   already running, so it can change course between tool
+ *                   calls. Answers "injected", or "startedNewTurn" if the turn
+ *                   beat us to the finish. An injected reply streams as
+ *                   `session/update` notifications inside that turn, whose
+ *                   `stopReason` waits for it. "startedNewTurn" output belongs
+ *                   to a detached turn no `session/prompt` of ours tracks.
+ *                   See ./steering.ts.
+ *   !queue <text>   `session/prompt` sent mid-turn anyway. The agent advertises
+ *                   `promptQueueing`, so it takes the backlog instead of us —
+ *                   same ordering, different owner.
+ *   !cancel         `session/cancel` for the running turn, as Ctrl-C does.
+ *
+ * Run (build the agent first so `dist/index.js` exists):
+ *
+ *   npm run build
+ *   node examples/simple-client.ts
+ *
+ * or, equivalently, `npm run example:simple-client`.
+ *
+ * To debug the agent itself, pass a port. The agent is then rebuilt with source
+ * maps and started under `--inspect-brk=<port>`, i.e. paused before its first
+ * line, so you can attach (IntelliJ: Run → Attach to Node.js/Chrome; VS Code:
+ * "Attach to Node Process"), set breakpoints in `src/*.ts`, and resume:
+ *
+ *   node examples/simple-client.ts --debug-port=9229
+ *
+ * The client will sit waiting for `initialize` until you attach and resume —
+ * that is expected, ACP has no request timeout.
+ *
+ * (Node < 22.18 needs `node --experimental-strip-types examples/simple-client.ts`.)
+ *
+ * Keys: Enter sends (or buffers), Ctrl-C cancels the running turn (again to
+ * quit), Ctrl-D drains anything buffered and exits. `!help` lists the commands.
+ *
+ * Flags: --debug-port=<port>, --no-build, --help.
+ * Env:   AGENT_ENTRY (default dist/index.js), CWD (default process.cwd()).
+ *
+ * Requires the agent to be authenticated, since it talks to the real model.
+ *
+ * Note: this client does not advertise the `elicitation` capability, so the
+ * agent disables its AskUserQuestion tool instead of asking us to render a
+ * form. That is the one intentional behaviour difference from a full client.
+ */
+import { spawn } from "node:child_process";
+import { once } from "node:events";
+import { existsSync } from "node:fs";
+import path from "node:path";
+import readline from "node:readline";
+import { Readable, Writable } from "node:stream";
+import { fileURLToPath } from "node:url";
+import {
+  PROTOCOL_VERSION,
+  client as acpClient,
+  methods,
+  ndJsonStream,
+} from "@agentclientprotocol/sdk";
+// Type-only: Node's type stripping does not elide value imports, and these two
+// exist only in the .d.ts — importing them normally is a runtime SyntaxError.
+import type { AnyMessage, Stream } from "@agentclientprotocol/sdk";
+
+// ---------------------------------------------------------------- steering
+
+/**
+ * The steering extension (../steering_protocol.md, and ./steering.ts for a
+ * scripted walkthrough). It is not part of ACP proper, so it has no entry in
+ * `methods` and is sent as a raw method name with hand-written types.
+ */
+const STEERING_METHOD = "_session/steering";
+
+type SteeringRequest = {
+  sessionId: string;
+  prompt: Array<{ type: "text"; text: string }>;
+};
+
+/** Both outcomes are successes; they say where the message landed, not whether
+ *  it worked. "startedNewTurn" means the turn finished before we got there. */
+type SteeringResponse = {
+  outcome: "injected" | "startedNewTurn";
+};
+
+// ---------------------------------------------------------------- arguments
+
+const ARGV = process.argv.slice(2);
+
+/** Reads `--name=value` or `--name value`; returns "" for a valueless flag. */
+function flag(name: string): string | undefined {
+  const index = ARGV.findIndex((arg) => arg === `--${name}` || arg.startsWith(`--${name}=`));
+  if (index === -1) return undefined;
+  const [, ...rest] = ARGV[index].split("=");
+  return rest.length > 0 ? rest.join("=") : (ARGV[index + 1] ?? "");
+}
+
+if (ARGV.includes("--help") || ARGV.includes("-h")) {
+  process.stdout.write(
+    [
+      "Usage: node examples/simple-client.ts [--debug-port=<port>] [--no-build]",
+      "",
+      "  --debug-port=<port>  rebuild with source maps and start the agent under",
+      "                       --inspect-brk=<port>, paused until a debugger attaches",
+      "  --no-build           skip the tsc rebuild and use dist/ as-is",
+      "",
+      "Env: AGENT_ENTRY (default dist/index.js), CWD (default process.cwd()).",
+      "",
+    ].join("\n"),
+  );
+  process.exit(0);
+}
+
+// The built agent entry. Rebuilt below unless --no-build is passed.
+const repoRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const AGENT_ENTRY = process.env.AGENT_ENTRY ?? path.join(repoRoot, "dist", "index.js");
+const CWD = process.env.CWD ?? process.cwd();
+const BUILD = !ARGV.includes("--no-build");
+
+const debugPortArg = flag("debug-port");
+const DEBUG_PORT = debugPortArg === undefined ? undefined : Number(debugPortArg);
+if (
+  DEBUG_PORT !== undefined &&
+  (!Number.isInteger(DEBUG_PORT) || DEBUG_PORT < 1 || DEBUG_PORT > 65535)
+) {
+  process.stderr.write(`--debug-port expects a port between 1 and 65535, got "${debugPortArg}"\n`);
+  process.exit(1);
+}
+
+/** Shown by `!help`, and once at startup. */
+const HELP = [
+  "<text>          send it — as a new turn, or buffered until this turn ends",
+  "!steer <text>   inject into the running turn (_session/steering)",
+  "!queue <text>   send session/prompt now and let the agent queue it",
+  "!cancel         session/cancel the running turn (same as Ctrl-C)",
+  "!help           this list; !! sends a line that really starts with '!'",
+];
+
+// How long to wait for a cancelled turn to settle, and for the agent to exit
+// after we close its stdin, before escalating during shutdown.
+const CANCEL_TIMEOUT_MS = 5_000;
+const EXIT_TIMEOUT_MS = 5_000;
+
+// ---------------------------------------------------------------- output
+
+const COLOR = process.stderr.isTTY === true && !process.env.NO_COLOR;
+const paint = (code: string, text: string) => (COLOR ? `\x1b[${code}m${text}\x1b[0m` : text);
+const dim = (text: string) => paint("2", text);
+
+const TTY = process.stdin.isTTY === true && process.stderr.isTTY === true;
+const startedAt = Date.now();
+
+let rl: readline.Interface | null = null;
+let shuttingDown = false;
+let queue: string[] = [];
+// How many `session/prompt` requests are awaiting a response. Usually 0 or 1;
+// `!queue` deliberately drives it higher to exercise the agent's own queueing.
+let inFlight = 0;
+const turnRunning = () => inFlight > 0;
+let cancelRequested = false;
+let lastUpdateKind = "";
+// False until `initialize` returns — an agent still paused under --inspect-brk
+// will never act on stdin EOF, so shutdown skips straight to signalling it.
+let agentReady = false;
+
+/**
+ * The single writer for everything this process prints. It wipes the half-typed
+ * input line, writes the block, then asks readline to redraw its prompt with the
+ * buffer intact — without this, streamed output and typing shred each other.
+ * (One caveat: a soft-wrapped input line leaves a stale fragment behind, since
+ * clearLine only clears the row the cursor is on.)
+ */
+function writeBlock(text: string) {
+  if (TTY) {
+    readline.cursorTo(process.stderr, 0);
+    readline.clearLine(process.stderr, 0);
+  }
+  process.stderr.write(text.endsWith("\n") ? text : `${text}\n`);
+  if (TTY) rl?.prompt(true);
+}
+
+function log(message: string) {
+  writeBlock(`${dim("[client]")} ${message}`);
+}
+
+function refreshPrompt() {
+  if (!rl) return;
+  const queued = queue.length > 0 ? `[${queue.length} queued] ` : "";
+  const running = inFlight > 1 ? `[${inFlight} turns] ` : "";
+  const busy = turnRunning() ? dim(`⋯ ${lastUpdateKind} `) : "";
+  rl.setPrompt(`${busy}${running}${queued}› `);
+  if (TTY) rl.prompt(true);
+}
+
+const delay = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
+
+// ---------------------------------------------------------------- wire log
+
+/** A permissive view of the JSON-RPC union, purely for the summary line. */
+type WireMessage = {
+  id?: string | number | null;
+  method?: string;
+  params?: { update?: { sessionUpdate?: string } };
+  result?: { stopReason?: string };
+  error?: { code: number; message: string };
+};
+
+/** One-line summary: method (plus session update kind), or which reply this is. */
+function describe(message: AnyMessage): string {
+  const wire = message as WireMessage;
+  const id = wire.id === undefined || wire.id === null ? "" : ` #${wire.id}`;
+  if (wire.method !== undefined) {
+    const kind = wire.params?.update?.sessionUpdate;
+    return `${wire.method}${kind ? ` · ${kind}` : ""}${id}`;
+  }
+  if (wire.error !== undefined) {
+    return `error${id} · ${wire.error.code} ${wire.error.message}`;
+  }
+  const stopReason = wire.result?.stopReason;
+  return `result${id}${stopReason ? ` · ${stopReason}` : ""}`;
+}
+
+/**
+ * Prints one JSON-RPC message. The SDK exposes no logging hook, so this is
+ * called from a stream tap (see `tapStream`) that sits between the SDK and the
+ * transport — what you see is exactly what is written to / read from the pipe.
+ */
+function logMessage(direction: "agent" | "user", message: AnyMessage) {
+  const inbound = direction === "agent";
+  const color = inbound ? "36" : "35";
+  const elapsed = ((Date.now() - startedAt) / 1000).toFixed(3);
+  const header = [
+    dim(`+${elapsed}s`),
+    paint(`1;${color}`, inbound ? "[agent]" : "[user] "),
+    paint(color, inbound ? "◂" : "▸"),
+    dim(describe(message)),
+  ].join(" ");
+  // The body is printed flush left and unadorned so that selecting it in the
+  // terminal yields valid JSON you can paste straight into a tool.
+  writeBlock(`${header}\n${JSON.stringify(message, null, 2)}`);
+}
+
+/**
+ * Wraps a transport stream so every message is logged post-parse/pre-stringify.
+ * A TransformStream per direction is the only complete interposition point: the
+ * SDK reads inbound with a single reader and takes a fresh writer per outbound
+ * message, and both survive being handed a transform.
+ */
+function tapStream(inner: Stream): Stream {
+  const inbound = new TransformStream<AnyMessage, AnyMessage>({
+    transform(message, controller) {
+      logMessage("agent", message);
+      controller.enqueue(message);
+    },
+  });
+  const outbound = new TransformStream<AnyMessage, AnyMessage>({
+    transform(message, controller) {
+      logMessage("user", message);
+      controller.enqueue(message);
+    },
+  });
+  // The SDK never closes its writable, so this pipe only settles on failure —
+  // typically the agent died and its stdin is gone. Teardown handles the rest;
+  // without the catch this would be an unhandled rejection.
+  outbound.readable.pipeTo(inner.writable).catch((err) => {
+    if (!shuttingDown) log(`transport write failed: ${err}`);
+  });
+  return { readable: inner.readable.pipeThrough(inbound), writable: outbound.writable };
+}
+
+// ---------------------------------------------------------------- build
+
+/** Runs the repo's tsc, sending its diagnostics to our stderr. */
+async function build(sourceMaps: boolean) {
+  const localTsc = path.join(repoRoot, "node_modules", "typescript", "bin", "tsc");
+  const useLocal = existsSync(localTsc);
+  const args = sourceMaps ? ["--sourceMap"] : [];
+  log(`building agent (tsc${sourceMaps ? " --sourceMap" : ""}) …`);
+
+  const child = useLocal
+    ? spawn(process.execPath, [localTsc, ...args], { cwd: repoRoot, stdio: ["ignore", 2, 2] })
+    : spawn(process.platform === "win32" ? "npx.cmd" : "npx", ["tsc", ...args], {
+        cwd: repoRoot,
+        stdio: ["ignore", 2, 2],
+      });
+
+  const [code] = (await once(child, "exit")) as [number | null];
+  if (code !== 0) {
+    log(`build failed (tsc exit ${code}) — fix the errors above, or pass --no-build`);
+    process.exit(1);
+  }
+}
+
+// ---------------------------------------------------------------- main
+
+async function main() {
+  if (BUILD) {
+    await build(DEBUG_PORT !== undefined);
+  } else if (!existsSync(AGENT_ENTRY)) {
+    log(`${AGENT_ENTRY} not found — run \`npm run build\` first, or unset --no-build`);
+    process.exit(1);
+  }
+
+  // An ACP client launches the agent as a subprocess and speaks JSON-RPC over
+  // its stdin/stdout. Its stderr is piped rather than inherited so that agent
+  // logs go through writeBlock() and don't corrupt the readline input line.
+  const nodeArgs =
+    DEBUG_PORT === undefined ? [AGENT_ENTRY] : [`--inspect-brk=${DEBUG_PORT}`, AGENT_ENTRY];
+  const child = spawn(process.execPath, nodeArgs, {
+    cwd: repoRoot,
+    stdio: ["pipe", "pipe", "pipe"],
+    env: process.env,
+  });
+  child.on("error", (err) => {
+    log(`failed to spawn agent (${AGENT_ENTRY}): ${err}`);
+    process.exit(1);
+  });
+  // A write racing the agent's exit surfaces as an unhandled 'error' event that
+  // would take this client down with it.
+  child.stdin?.on("error", (err: NodeJS.ErrnoException) => {
+    if (err.code !== "EPIPE") log(`agent stdin error: ${err}`);
+  });
+  child.stdout?.on("error", () => {});
+  process.stderr.on("error", () => {});
+
+  pumpAgentStderr(child);
+
+  child.on("exit", (code, signal) => {
+    if (!shuttingDown) log(`agent exited (code ${code}, signal ${signal})`);
+  });
+
+  const stream = tapStream(
+    ndJsonStream(
+      Writable.toWeb(child.stdin!) as WritableStream<Uint8Array>,
+      Readable.toWeb(child.stdout!) as unknown as ReadableStream<Uint8Array>,
+    ),
+  );
+
+  const connection = acpClient({ name: "simple-client" })
+    // The tap already prints every update; this handler exists so the prompt line
+    // can show what the agent is currently doing.
+    .onNotification(methods.client.session.update, (ctx) => {
+      lastUpdateKind = ctx.params.update.sessionUpdate;
+    })
+    // Auto-approve, chosen by `kind` and never by a hard-coded optionId: for
+    // ExitPlanMode this agent uses permission-*mode* names as option ids
+    // (auto / acceptEdits / default / plan / bypassPermissions).
+    .onRequest(methods.client.session.requestPermission, (ctx) => {
+      const options = ctx.params.options;
+      const option = options.find((o) => o.kind === "allow_once") ?? options[0];
+      if (!option) return { outcome: { outcome: "cancelled" } };
+      log(`auto-approving permission: ${option.name} (${option.kind}/${option.optionId})`);
+      return { outcome: { outcome: "selected", optionId: option.optionId } };
+    })
+    // Minimal file-system stubs. This agent performs its own file I/O inside the
+    // Claude Agent SDK subprocess and never calls these today.
+    .onRequest(methods.client.fs.readTextFile, () => ({ content: "" }))
+    .onRequest(methods.client.fs.writeTextFile, () => ({}))
+    .connect(stream);
+
+  const agent = connection.agent;
+
+  // Signals are wired up *before* the first request. Under --inspect-brk the
+  // wait below is unbounded, and a client that dies without running shutdown()
+  // orphans a paused agent still holding the debug port.
+  const onInterrupt = () => {
+    if (turnRunning() && !cancelRequested) {
+      cancelRequested = true;
+      const dropped = queue.length;
+      queue = [];
+      // A notification, not a request: every turn in flight settles through its
+      // own session/prompt response, normally with stopReason "cancelled".
+      void agent.notify(methods.agent.session.cancel, { sessionId });
+      log(`sent session/cancel${dropped > 0 ? `, dropped ${dropped} queued line(s)` : ""}`);
+      refreshPrompt();
+      return;
+    }
+    void shutdown(turnRunning() ? "^C while cancelling" : "^C");
+  };
+  // In terminal mode readline puts stdin in raw mode and owns ^C, so this only
+  // ever fires for an explicit `kill -INT`; with piped stdin it is the ^C path.
+  process.on("SIGINT", onInterrupt);
+  process.on("SIGTERM", () => void shutdown("SIGTERM"));
+
+  // 1. Initialize. Under --inspect-brk the agent is paused before it reads a
+  //    single byte, so this request stays unanswered until a debugger attaches
+  //    and resumes it. ACP has no request timeout, so waiting is safe; the
+  //    interval below just keeps the terminal from looking dead.
+  let nudge: NodeJS.Timeout | undefined;
+  if (DEBUG_PORT !== undefined) {
+    log(`agent is PAUSED before its first line (--inspect-brk=${DEBUG_PORT})`);
+    log(`attach a debugger to port ${DEBUG_PORT} and resume it — breakpoints go in src/*.ts`);
+    nudge = setInterval(
+      () => log(`still waiting for a debugger on port ${DEBUG_PORT} … (Ctrl-C to give up)`),
+      10_000,
+    );
+  }
+  let init;
+  try {
+    init = await agent.request(methods.agent.initialize, {
+      protocolVersion: PROTOCOL_VERSION,
+      clientCapabilities: {
+        fs: { readTextFile: true, writeTextFile: true },
+        terminal: false,
+      },
+    });
+  } finally {
+    if (nudge) clearInterval(nudge);
+  }
+  agentReady = true;
+  log(`connected to ${init.agentInfo?.name ?? "agent"} ${init.agentInfo?.version ?? ""}`.trim());
+
+  // Steering is advertised at the TOP-LEVEL `_meta` of the initialize result —
+  // a sibling of `agentCapabilities`, not nested inside it. Prompt queueing is
+  // a Claude-specific capability flag and does live inside.
+  const initMeta = init._meta as { steering?: { supported?: boolean } } | null | undefined;
+  const steeringSupported = initMeta?.steering?.supported === true;
+  const queueMeta = init.agentCapabilities?._meta as
+    { claudeCode?: { promptQueueing?: boolean } } | null | undefined;
+  log(
+    `agent supports: steering=${steeringSupported} ` +
+      `promptQueueing=${queueMeta?.claudeCode?.promptQueueing === true}`,
+  );
+
+  // 2. Open a session.
+  let sessionId: string;
+  try {
+    const session = await agent.request(methods.agent.session.new, { cwd: CWD, mcpServers: [] });
+    sessionId = session.sessionId;
+  } catch (err) {
+    log(`session/new failed: ${err}`);
+    log("if this is an auth error, log in first: node dist/index.js --cli auth login");
+    await shutdown("session/new failed", 1);
+    return;
+  }
+  log(`session ${sessionId} in ${CWD}`);
+
+  // 3. Turns. There are four ways to get a message to the agent, and the client
+  //    can drive all of them (see `handleCommand`); plain text uses the first.
+  //
+  //      session/prompt      a new turn, or — for text typed mid-turn — one
+  //                          buffered here and sent when the turn responds
+  //      session/prompt      sent mid-turn anyway, so the *agent* queues it
+  //        (!queue)          (it advertises `_meta.claudeCode.promptQueueing`)
+  //      _session/steering   injected into the turn that is already running
+  //        (!steer)
+  //      session/cancel      abandon the running turn
+  //        (!cancel, ^C)
+  let draining = false;
+
+  /** One `session/prompt` round-trip. Several may be in flight at once when
+   *  `!queue` is used; the agent runs them in order. */
+  async function sendPrompt(text: string) {
+    inFlight += 1;
+    cancelRequested = false;
+    refreshPrompt();
+    try {
+      const result = await agent.request(methods.agent.session.prompt, {
+        sessionId,
+        prompt: [{ type: "text", text }],
+      });
+      log(`turn ended: ${result.stopReason}`);
+    } catch (err) {
+      // The error response itself was already printed by the tap; this is
+      // the human-readable "your prompt did not run".
+      log(`prompt failed: ${err}`);
+      if (connection.signal.aborted) queue = [];
+    } finally {
+      inFlight -= 1;
+      refreshPrompt();
+      exitWhenIdle();
+    }
+  }
+
+  /** Sends the buffered lines one turn at a time, oldest first. */
+  async function drain() {
+    if (draining) return;
+    draining = true;
+    try {
+      while (queue.length > 0 && !shuttingDown) {
+        await sendPrompt(queue.shift()!);
+        if (connection.signal.aborted) break;
+      }
+    } finally {
+      draining = false;
+      refreshPrompt();
+      exitWhenIdle();
+    }
+  }
+
+  /** A piped stdin ends; exiting has to wait for the work already handed out. */
+  function exitWhenIdle() {
+    if (inputClosed && !draining && queue.length === 0 && inFlight === 0) {
+      void shutdown("input closed, queue drained");
+    }
+  }
+
+  /**
+   * Client-side commands, prefixed with `!` so they cannot collide with the
+   * agent's own slash commands (`/compact` and friends, which are just prompt
+   * text as far as this client is concerned). `!!` escapes a literal `!`.
+   */
+  function handleCommand(line: string) {
+    const word = line.split(/\s+/)[0];
+    const text = line.slice(word.length).trim();
+    switch (word) {
+      case "!steer":
+        if (text.length === 0) {
+          log("usage: !steer <message> — injects into the turn that is running");
+          break;
+        }
+        if (!steeringSupported) log("agent did not advertise steering; trying anyway");
+        void steer(text);
+        break;
+      case "!queue":
+        if (text.length === 0) {
+          log("usage: !queue <message> — sends session/prompt now, agent queues it");
+          break;
+        }
+        void sendPrompt(text);
+        break;
+      case "!cancel":
+        if (!turnRunning()) {
+          log("nothing to cancel");
+          break;
+        }
+        onInterrupt();
+        break;
+      case "!help":
+        for (const entry of HELP) log(entry);
+        break;
+      default:
+        log(`unknown command ${word} — try !help`);
+        break;
+    }
+    refreshPrompt();
+  }
+
+  /** `_session/steering`: deliver a message to the turn already in progress. */
+  async function steer(text: string) {
+    const params: SteeringRequest = { sessionId, prompt: [{ type: "text", text }] };
+    try {
+      const result = await agent.request<SteeringResponse>(STEERING_METHOD, params);
+      // Either way the steered message's own output arrives as `session/update`
+      // notifications, not in this response. When injected, it lands inside the
+      // turn we steered, whose `stopReason` waits for it.
+      log(
+        result.outcome === "injected"
+          ? "steer outcome: injected into the running turn"
+          : "steer outcome: startedNewTurn — the turn had already finished, so the " +
+              "agent began a new one that no session/prompt of ours is tracking",
+      );
+    } catch (err) {
+      log(`steer rejected: ${err}`);
+    }
+  }
+
+  let inputClosed = false;
+  let steerHinted = false;
+
+  rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stderr,
+    terminal: TTY,
+    crlfDelay: Infinity,
+    historySize: 200,
+  });
+
+  rl.on("line", (raw) => {
+    const line = raw.trim();
+    if (line.length === 0 || shuttingDown) {
+      refreshPrompt();
+      return;
+    }
+    if (line.startsWith("!") && !line.startsWith("!!")) {
+      handleCommand(line);
+      return;
+    }
+    // "!!steer …" is how you send text that begins with the command prefix.
+    queue.push(line.startsWith("!!") ? line.slice(1) : line);
+    if (turnRunning()) {
+      log(`buffered — will send when this turn ends (${queue.length} queued)`);
+      if (!steerHinted) {
+        steerHinted = true;
+        log("…or use !steer <text> to inject into the running turn instead");
+      }
+    }
+    refreshPrompt();
+    void drain();
+  });
+
+  rl.on("SIGINT", onInterrupt);
+
+  rl.on("close", () => {
+    inputClosed = true;
+    exitWhenIdle();
+  });
+
+  void connection.closed.then(() => {
+    if (!shuttingDown) void shutdown("connection closed");
+  });
+
+  for (const entry of HELP) log(entry);
+  log("Enter sends, Ctrl-C cancels a turn, Ctrl-D exits");
+  refreshPrompt();
+
+  /**
+   * Order matters here. The agent exits cleanly on stdin EOF (src/index.ts wires
+   * `connection.closed` to `agent.dispose()`), whereas killing it skips disposal
+   * and can orphan the Claude Agent SDK subprocess. Closing our connection first
+   * would cancel the reader on the agent's stdout and make it die of EPIPE
+   * mid-write, so that comes last.
+   */
+  async function shutdown(reason: string, exitCode = 0) {
+    if (shuttingDown) return;
+    shuttingDown = true;
+    log(`shutting down (${reason})`);
+    queue = [];
+    rl?.removeAllListeners("close");
+    rl?.close();
+
+    if (turnRunning()) {
+      if (!cancelRequested) {
+        try {
+          await agent.notify(methods.agent.session.cancel, { sessionId });
+        } catch {
+          // The connection may already be gone; teardown continues regardless.
+        }
+      }
+      const deadline = Date.now() + CANCEL_TIMEOUT_MS;
+      while (turnRunning() && Date.now() < deadline) await delay(50);
+    }
+
+    child.stdin?.end();
+    const exited = await Promise.race([
+      once(child, "exit").then(() => true),
+      delay(agentReady ? EXIT_TIMEOUT_MS : 250).then(() => false),
+    ]);
+    if (!exited) {
+      log("agent did not exit on stdin EOF; sending SIGTERM");
+      child.kill("SIGTERM");
+      const stopped = await Promise.race([
+        once(child, "exit").then(() => true),
+        delay(2_000).then(() => false),
+      ]);
+      if (!stopped) child.kill("SIGKILL");
+    }
+
+    connection.close();
+    process.exit(exitCode);
+  }
+}
+
+/** Streams the agent's stderr through writeBlock, flagging inspector messages. */
+function pumpAgentStderr(child: ReturnType<typeof spawn>) {
+  let buffered = "";
+  child.stderr?.setEncoding("utf8");
+  child.stderr?.on("data", (chunk: string) => {
+    buffered += chunk;
+    const lines = buffered.split("\n");
+    buffered = lines.pop() ?? "";
+    for (const line of lines) {
+      if (line.length === 0) continue;
+      if (line.includes("Debugger listening on")) {
+        writeBlock(paint("1;33", `[agent] ${line.trim()}`));
+      } else if (line.includes("address already in use")) {
+        writeBlock(paint("1;31", `[agent] ${line.trim()}`));
+        log("that inspector port is taken — pass a different --debug-port");
+      } else {
+        writeBlock(dim(`[agent:stderr] ${line}`));
+      }
+    }
+  });
+}
+
+main().catch((err) => {
+  // Tearing down rejects whatever request main() is awaiting; that is the
+  // teardown finishing its job, not a failure, and shutdown() owns the exit.
+  if (shuttingDown) return;
+  log(`fatal: ${err?.stack ?? err}`);
+  process.exit(1);
+});

package.json

@@ -3,7 +3,7 @@
   "publishConfig": {
     "access": "public"
   },
-  "version": "0.64.1",
+  "version": "0.84.0",
   "description": "An ACP-compatible coding agent powered by the Claude Agent SDK (TypeScript)",
   "main": "dist/lib.js",
   "types": "dist/lib.d.ts",
@@ -29,11 +29,13 @@
     "build": "tsc",
     "start": "node dist/index.js",
     "dev": "npm run build && npm run start",
+    "example:simple-client": "node --experimental-strip-types --disable-warning=ExperimentalWarning examples/simple-client.ts",
     "lint": "eslint src --ext .ts",
     "lint:fix": "eslint src --ext .ts --fix",
     "format": "prettier --write .",
     "format:check": "prettier --check .",
     "check": "npm run lint && npm run format:check",
+    "release:preflight": "bash scripts/release-preflight.sh",
     "test": "vitest",
     "test:integration": "RUN_INTEGRATION_TESTS=true vitest run",
     "test:run": "vitest run",
@@ -63,23 +65,26 @@
     "node": ">=22"
   },
   "dependencies": {
-    "@agentclientprotocol/sdk": "1.3.0",
-    "@anthropic-ai/claude-agent-sdk": "0.3.220",
-    "zod": "^3.25.0 || ^4.0.0"
+    "@agentclientprotocol/sdk": "1.5.1",
+    "@anthropic-ai/claude-agent-sdk": "0.3.284",
+    "diff": "9.0.0",
+    "zod": "4.6.5"
   },
   "devDependencies": {
-    "@anthropic-ai/sdk": "0.115.0",
+    "@anthropic-ai/sdk": "0.128.0",
     "@eslint/js": "10.0.1",
-    "@tsconfig/node22": "22.0.5",
-    "@types/node": "26.1.2",
-    "@typescript-eslint/eslint-plugin": "8.65.0",
-    "@typescript-eslint/parser": "8.65.0",
-    "eslint": "10.8.0",
+    "@tsconfig/node22": "22.0.6",
+    "@types/node": "26.6.3",
+    "@typescript-eslint/eslint-plugin": "8.70.1",
+    "@typescript-eslint/parser": "8.70.1",
+    "ajv": "8.20.0",
+    "ajv-formats": "3.0.1",
+    "eslint": "10.11.0",
     "eslint-config-prettier": "10.1.8",
-    "globals": "17.8.0",
-    "prettier": "3.9.6",
+    "globals": "17.12.0",
+    "prettier": "3.9.9",
     "ts-node": "10.9.2",
     "typescript": "6.0.3",
-    "vitest": "4.1.10"
+    "vitest": "5.0.2"
   }
 }

release-please-config.json

@@ -1,12 +1,12 @@
 {
   "bump-minor-pre-major": true,
-  "bump-patch-for-minor-pre-major": true,
+  "include-component-in-tag": false,
   "packages": {
     ".": {
       "changelog-path": "CHANGELOG.md",
       "release-type": "node",
       "bump-minor-pre-major": true,
-      "bump-patch-for-minor-pre-major": true
+      "include-component-in-tag": false
     }
   },
   "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"

scripts/next-preview-version.mjs

@@ -0,0 +1,202 @@
+#!/usr/bin/env node
+//
+// Prints the next preview version for this package, e.g. `0.73.1-preview.4`.
+//
+// The base is package.json's version with the patch incremented, so a preview always
+// sorts above the last release and below whatever release follows it. `-preview.N`
+// counts from 1 per base and restarts whenever release-please moves package.json on.
+//
+// Basing the preview on release-please's *predicted* next version would be more
+// truthful — it would give `0.74.0-preview.N` when a `feat:` is queued — but the
+// prediction moves mid-flight: a `fix:` opens a 0.73.1 release PR, a later `feat:`
+// moves it to 0.74.0, and N resets under previews that were already published. If the
+// prediction ever moved down, the next preview would sort below the previous one.
+// package.json only ever increases, so patch+1 is monotonic in every case:
+// 0.73.1-preview.9 < 0.73.2-preview.1 and < 0.74.1-preview.1, whichever way the next
+// release goes. The cost is that `0.73.1-preview.4` is not a promise that 0.73.1 will
+// ship.
+//
+// N has to be a number nobody has used, and two sources are consulted because either
+// alone is unsafe:
+//
+//   * the npm registry, authoritative for what is taken — npm versions are immutable
+//     and stay reserved even after `npm unpublish`, so a taken N is a hard E403 at
+//     publish time — but served from a CDN, so it can lag a publish by minutes;
+//   * git tags, written by the workflow after each publish and strongly consistent,
+//     which cover that window and any unpublish.
+//
+// The workflow publishes before it tags, so a version can exist on npm without a tag
+// but never the other way round. That asymmetry is why the registry is the authority
+// and the tags are only a floor, and why a registry read failure is fatal here rather
+// than falling back to the tags alone.
+//
+// See docs/RELEASES.md.
+
+import { execFileSync } from "node:child_process";
+import { readFileSync } from "node:fs";
+import { pathToFileURL } from "node:url";
+
+const DEFAULT_REGISTRY = "https://registry.npmjs.org";
+const PREVIEW_ID = "preview";
+const FETCH_ATTEMPTS = 3;
+const FETCH_TIMEOUT_MS = 10_000;
+const BACKOFF_MS = 500;
+
+/** X.Y.Z: no prerelease, no build metadata, no leading zeros. */
+const RELEASE_VERSION = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)$/;
+
+/** The base a preview anticipates: package.json's version with the patch bumped. */
+export function bumpPatch(version) {
+  const match = RELEASE_VERSION.exec(String(version ?? "").trim());
+  if (!match) {
+    throw new Error(
+      `expected a plain X.Y.Z release version, got ${JSON.stringify(version)}. ` +
+        `release-please owns package.json's version; a prerelease or a range here means ` +
+        `something else has edited it.`,
+    );
+  }
+  const [, major, minor, patch] = match;
+  return `${major}.${minor}.${Number(patch) + 1}`;
+}
+
+function escapeRegExp(literal) {
+  return literal.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+/**
+ * Matcher for `<base>-preview.<n>`. `0731-preview.1` would match a base of `0.73.1`. `n`
+ * is a semver-legal numeric identifier, so leading zeros are rejected; npm would never
+ * have accepted `preview.01` in the first place.
+ */
+export function previewPattern(base) {
+  return new RegExp(`^${escapeRegExp(base)}-${PREVIEW_ID}\\.(0|[1-9]\\d*)$`);
+}
+
+/** The N in `<base>-preview.N`, or null for anything else. */
+export function previewNumber(candidate, base) {
+  const match = previewPattern(base).exec(String(candidate ?? "").trim());
+  return match ? Number(match[1]) : null;
+}
+
+/** `refs/tags/v1.2.3`, `v1.2.3` and `1.2.3` all become `1.2.3`. */
+export function versionFromTag(tag) {
+  return String(tag ?? "")
+    .trim()
+    .replace(/^refs\/tags\//, "")
+    .replace(/^v/, "");
+}
+
+/**
+ * Highest N among the candidates, or 0 when none match.
+ */
+export function highestPreviewNumber(candidates, base) {
+  let highest = 0;
+  for (const candidate of candidates) {
+    const n = previewNumber(candidate, base);
+    if (n !== null && n > highest) {
+      highest = n;
+    }
+  }
+  return highest;
+}
+
+export function nextPreviewVersion({ base, registryVersions = [], tags = [] }) {
+  const taken = Math.max(
+    highestPreviewNumber(registryVersions, base),
+    highestPreviewNumber(tags.map(versionFromTag), base),
+  );
+  return `${base}-${PREVIEW_ID}.${taken + 1}`;
+}
+
+/** Every version this package has ever published, per the registry. */
+export async function fetchPublishedVersions(name, options = {}) {
+  const {
+    registry = DEFAULT_REGISTRY,
+    fetchImpl = fetch,
+    attempts = FETCH_ATTEMPTS,
+    backoffMs = BACKOFF_MS,
+  } = options;
+  const url = `${registry}/${name.replace("/", "%2f")}`;
+  let lastError;
+  for (let attempt = 1; attempt <= attempts; attempt++) {
+    try {
+      const response = await fetchImpl(url, {
+        // The abbreviated packument is a fraction of the full one — tens of kilobytes
+        // rather than megabytes — and still carries every version key.
+        headers: { accept: "application/vnd.npm.install-v1+json" },
+        signal: AbortSignal.timeout(FETCH_TIMEOUT_MS),
+      });
+      if (response.status === 404) {
+        // Never published. A definite answer, not a failure.
+        return [];
+      }
+      if (!response.ok) {
+        throw new Error(`${url} answered ${response.status} ${response.statusText}`);
+      }
+      const packument = await response.json();
+      // `versions` on a packument is always an object keyed by version, so there is
+      // none of the "a single version comes back as a bare string" shape that
+      // `npm view <pkg> versions --json` has.
+      return Object.keys(packument.versions ?? {});
+    } catch (error) {
+      lastError = error;
+      if (attempt < attempts) {
+        await new Promise((resolve) => setTimeout(resolve, backoffMs * 2 ** (attempt - 1)));
+      }
+    }
+  }
+  throw new Error(
+    `could not read published versions for ${name} after ${attempts} attempts: ${lastError}. ` +
+      `Refusing to guess a preview number: the registry is the only record of versions ` +
+      `that were published and then unpublished, and those can never be reused.`,
+    { cause: lastError },
+  );
+}
+
+function localPreviewTags(base) {
+  try {
+    return execFileSync("git", ["tag", "--list", `v${base}-${PREVIEW_ID}.*`], {
+      encoding: "utf8",
+      stdio: ["ignore", "pipe", "ignore"],
+    })
+      .split("\n")
+      .filter(Boolean);
+  } catch {
+    // No git, no repository, or a clone without tags. Tags are only a floor under the
+    // registry, so carry on rather than fail.
+    process.stderr.write("warning: could not list git tags; using the registry alone\n");
+    return [];
+  }
+}
+
+function readFlag(argv, name) {
+  const index = argv.indexOf(name);
+  return index === -1 ? undefined : argv[index + 1];
+}
+
+async function main(argv) {
+  const packageJsonPath = readFlag(argv, "--package-json") ?? "package.json";
+  const manifest = JSON.parse(readFileSync(packageJsonPath, "utf8"));
+  const base = bumpPatch(manifest.version);
+  const registryVersions = await fetchPublishedVersions(manifest.name, {
+    registry: readFlag(argv, "--registry") ?? DEFAULT_REGISTRY,
+  });
+  const tags = argv.includes("--no-git-tags") ? [] : localPreviewTags(base);
+
+  // Diagnostics on stderr so stdout stays a single machine-readable line.
+  process.stderr.write(
+    `${manifest.name} ${manifest.version} -> base ${base}; registry high-water ` +
+      `${highestPreviewNumber(registryVersions, base)}, tag high-water ` +
+      `${highestPreviewNumber(tags.map(versionFromTag), base)}\n`,
+  );
+  process.stdout.write(`${nextPreviewVersion({ base, registryVersions, tags })}\n`);
+}
+
+// Only when invoked as a program, so the helpers above can be imported by the test
+// without doing any I/O.
+if (import.meta.url === pathToFileURL(process.argv[1] ?? "").href) {
+  main(process.argv.slice(2)).catch((error) => {
+    process.stderr.write(`${error.message}\n`);
+    process.exit(1);
+  });
+}

scripts/next-preview-version.test.mjs

@@ -0,0 +1,249 @@
+import { describe, it, expect, vi } from "vitest";
+import {
+  bumpPatch,
+  previewNumber,
+  versionFromTag,
+  highestPreviewNumber,
+  nextPreviewVersion,
+  fetchPublishedVersions,
+} from "./next-preview-version.mjs";
+
+const PACKAGE = "@agentclientprotocol/claude-agent-acp";
+
+/** A packument response, abbreviated the way the registry returns it. */
+function packument(versions) {
+  return {
+    ok: true,
+    status: 200,
+    statusText: "OK",
+    json: async () => ({ name: PACKAGE, versions }),
+  };
+}
+
+function failure(status, statusText = "Internal Server Error") {
+  return { ok: false, status, statusText, json: async () => ({}) };
+}
+
+describe("bumpPatch", () => {
+  it("increments the patch", () => {
+    expect(bumpPatch("0.73.0")).toBe("0.73.1");
+    expect(bumpPatch("1.0.0")).toBe("1.0.1");
+    expect(bumpPatch("0.0.0")).toBe("0.0.1");
+  });
+
+  it("increments numerically rather than by concatenation", () => {
+    expect(bumpPatch("0.73.9")).toBe("0.73.10");
+    expect(bumpPatch("0.73.19")).toBe("0.73.20");
+  });
+
+  it("trims surrounding whitespace", () => {
+    expect(bumpPatch(" 0.73.0 ")).toBe("0.73.1");
+  });
+
+  // release-please owns package.json's version, so anything that is not a plain
+  // release means something else has edited it. Failing loudly beats guessing.
+  it.each([
+    ["a two-part version", "0.73"],
+    ["a four-part version", "0.73.0.1"],
+    ["a prerelease", "0.73.0-preview.1"],
+    ["build metadata", "0.73.0+build.1"],
+    ["a v prefix", "v0.73.0"],
+    ["a range", "^0.73.0"],
+    ["leading zeros", "01.2.3"],
+    ["the empty string", ""],
+    ["undefined", undefined],
+  ])("throws on %s", (_label, version) => {
+    expect(() => bumpPatch(version)).toThrow(/plain X\.Y\.Z release version/);
+  });
+});
+
+describe("previewNumber", () => {
+  it("reads N out of a matching version", () => {
+    expect(previewNumber("0.73.1-preview.1", "0.73.1")).toBe(1);
+    expect(previewNumber("0.73.1-preview.10", "0.73.1")).toBe(10);
+  });
+
+  it("treats zero as a number rather than as no match", () => {
+    expect(previewNumber("0.73.1-preview.0", "0.73.1")).toBe(0);
+  });
+
+  it.each([
+    ["a plain release", "0.73.1"],
+    ["a different base", "0.73.2-preview.1"],
+    ["a missing number", "0.73.1-preview"],
+    ["leading zeros in N", "0.73.1-preview.01"],
+    ["a dotted N", "0.73.1-preview.1.2"],
+    ["build metadata", "0.73.1-preview.1+build.5"],
+    ["another prerelease id", "0.73.1-alpha.1"],
+    // Proves the base's dots are escaped rather than matching any character.
+    ["a base whose dots are elided", "0731-preview.1"],
+    // Proves the pattern is anchored at the start.
+    ["a base with a numeric prefix", "10.73.1-preview.1"],
+  ])("returns null for %s", (_label, candidate) => {
+    expect(previewNumber(candidate, "0.73.1")).toBeNull();
+  });
+});
+
+describe("versionFromTag", () => {
+  it("strips a refs/tags/ prefix and a v", () => {
+    expect(versionFromTag("refs/tags/v0.73.1-preview.3")).toBe("0.73.1-preview.3");
+    expect(versionFromTag("v0.73.1")).toBe("0.73.1");
+    expect(versionFromTag("0.73.1")).toBe("0.73.1");
+  });
+});
+
+describe("highestPreviewNumber", () => {
+  it("is 0 when nothing matches", () => {
+    expect(highestPreviewNumber([], "0.73.1")).toBe(0);
+    expect(highestPreviewNumber(["0.73.1", "0.72.1-preview.4"], "0.73.1")).toBe(0);
+  });
+
+  // Sorted as strings, `preview.9` would beat `preview.10`.
+  it("compares numerically, not lexicographically", () => {
+    expect(highestPreviewNumber(["0.73.1-preview.9", "0.73.1-preview.10"], "0.73.1")).toBe(10);
+    expect(highestPreviewNumber(["0.73.1-preview.10", "0.73.1-preview.9"], "0.73.1")).toBe(10);
+  });
+
+  it("ignores order and duplicates", () => {
+    const candidates = [
+      "0.73.1-preview.2",
+      "0.73.1-preview.7",
+      "0.73.1-preview.2",
+      "0.73.1-preview.5",
+    ];
+    expect(highestPreviewNumber(candidates, "0.73.1")).toBe(7);
+  });
+
+  it("counts only the requested base", () => {
+    const candidates = ["0.72.1-preview.99", "0.73.1-preview.3", "0.74.1-preview.42"];
+    expect(highestPreviewNumber(candidates, "0.73.1")).toBe(3);
+  });
+});
+
+describe("nextPreviewVersion", () => {
+  it("starts at 1 with no history", () => {
+    expect(nextPreviewVersion({ base: "0.73.1" })).toBe("0.73.1-preview.1");
+  });
+
+  it("continues from the registry", () => {
+    const registryVersions = ["0.73.0", "0.73.1-preview.1", "0.73.1-preview.2", "0.73.1-preview.3"];
+    expect(nextPreviewVersion({ base: "0.73.1", registryVersions })).toBe("0.73.1-preview.4");
+  });
+
+  // The registry is CDN-served and can lag a publish by minutes; the tag the previous
+  // run wrote is what closes that window.
+  it("uses the tags as a floor when the registry is behind", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.73.1-preview.1"],
+      tags: ["refs/tags/v0.73.1-preview.3"],
+    });
+    expect(next).toBe("0.73.1-preview.4");
+  });
+
+  // The converse: publish succeeded but the tag step did not, so the registry is
+  // ahead. It stays authoritative.
+  it("keeps the registry authoritative when the tags are behind", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.73.1-preview.1", "0.73.1-preview.2", "0.73.1-preview.3"],
+      tags: ["v0.73.1-preview.1"],
+    });
+    expect(next).toBe("0.73.1-preview.4");
+  });
+
+  it("restarts at 1 once a release moves the base", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.72.1-preview.7", "0.73.0"],
+      tags: ["v0.72.1-preview.7"],
+    });
+    expect(next).toBe("0.73.1-preview.1");
+  });
+
+  it("composes with bumpPatch", () => {
+    const next = nextPreviewVersion({
+      base: bumpPatch("0.73.0"),
+      registryVersions: ["0.73.0"],
+      tags: ["v0.73.0"],
+    });
+    expect(next).toBe("0.73.1-preview.1");
+  });
+});
+
+describe("fetchPublishedVersions", () => {
+  const options = (fetchImpl) => ({ fetchImpl, backoffMs: 0 });
+
+  it("returns the version keys of the packument", async () => {
+    const fetchImpl = vi.fn(async () => packument({ "0.73.0": {}, "0.73.1-preview.1": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([
+      "0.73.0",
+      "0.73.1-preview.1",
+    ]);
+  });
+
+  it("requests the abbreviated packument at the scope-encoded URL", async () => {
+    const fetchImpl = vi.fn(async () => packument({}));
+    await fetchPublishedVersions(PACKAGE, options(fetchImpl));
+    const [url, init] = fetchImpl.mock.calls[0];
+    expect(url).toBe("https://registry.npmjs.org/@agentclientprotocol%2fclaude-agent-acp");
+    expect(init.headers.accept).toBe("application/vnd.npm.install-v1+json");
+  });
+
+  it("honours a custom registry", async () => {
+    const fetchImpl = vi.fn(async () => packument({}));
+    await fetchPublishedVersions(PACKAGE, {
+      ...options(fetchImpl),
+      registry: "http://127.0.0.1:4873",
+    });
+    expect(fetchImpl.mock.calls[0][0]).toBe(
+      "http://127.0.0.1:4873/@agentclientprotocol%2fclaude-agent-acp",
+    );
+  });
+
+  it("tolerates a packument with no versions", async () => {
+    const fetchImpl = vi.fn(async () => ({
+      ok: true,
+      status: 200,
+      statusText: "OK",
+      json: async () => ({ name: PACKAGE }),
+    }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([]);
+  });
+
+  // A 404 is a definite answer — the package has never been published — so it must not
+  // be retried or turned into a failure.
+  it("treats 404 as an empty history without retrying", async () => {
+    const fetchImpl = vi.fn(async () => failure(404, "Not Found"));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([]);
+    expect(fetchImpl).toHaveBeenCalledTimes(1);
+  });
+
+  it("retries a server error and resolves", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockResolvedValueOnce(failure(500))
+      .mockResolvedValueOnce(packument({ "0.73.0": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual(["0.73.0"]);
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+  });
+
+  it("retries a network failure and resolves", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockRejectedValueOnce(new TypeError("fetch failed"))
+      .mockResolvedValueOnce(packument({ "0.73.0": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual(["0.73.0"]);
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+  });
+
+  // Guessing N after a failed read risks reusing a version that was published and then
+  // unpublished, which npm reserves forever.
+  it("gives up rather than guessing when every attempt fails", async () => {
+    const fetchImpl = vi.fn(async () => failure(500));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).rejects.toThrow(
+      /could not read published versions for @agentclientprotocol\/claude-agent-acp after 3 attempts/,
+    );
+    expect(fetchImpl).toHaveBeenCalledTimes(3);
+  });
+});

scripts/release-preflight.sh

@@ -0,0 +1,124 @@
+#!/usr/bin/env bash
+#
+# Preflight checks for a release.
+#
+# release-please decides what the next version is; this script only verifies the
+# repository is in a state where merging the open release PR produces a correct
+# release. Merging main needs no review, so these checks are the only thing
+# standing between a mistake and a published package — keep them as code rather
+# than as a list someone has to remember. See docs/RELEASES.md.
+#
+# Requires an authenticated GitHub CLI. Nothing else: gh has a jq engine builtin.
+
+set -euo pipefail
+
+PENDING_LABEL="autorelease: pending"
+
+fail() {
+  printf 'FAIL  %s\n' "$1" >&2
+  exit 1
+}
+
+pass() {
+  printf 'ok    %s\n' "$1"
+}
+
+command -v gh >/dev/null 2>&1 ||
+  fail "GitHub CLI (gh) is not installed."
+gh auth status >/dev/null 2>&1 ||
+  fail "GitHub CLI is not authenticated. Run 'gh auth login'."
+
+repo=$(gh repo view --json nameWithOwner --jq .nameWithOwner 2>/dev/null) ||
+  fail "cannot work out which GitHub repository this is. Run from a checkout."
+
+# A merged release PR that still carries the pending label means release-please
+# never tagged it. In that state it refuses to open any new release PR at all,
+# so every later release stalls silently until it is recovered by hand.
+stuck=$(gh pr list --repo "$repo" --state merged --label "$PENDING_LABEL" \
+  --json number --jq 'map("#\(.number)") | join(", ")')
+[ -z "$stuck" ] ||
+  fail "merged release PR still labelled '$PENDING_LABEL': $stuck.
+      release-please is jammed and will not open new release PRs.
+      See docs/RELEASES.md, 'Recovering a stalled release'."
+pass "no untagged merged release PR"
+
+rows=$(gh pr list --repo "$repo" --state open --label "$PENDING_LABEL" \
+  --json number,title,headRefName --jq '.[] | [.number, .headRefName, .title] | @tsv')
+count=$(printf '%s\n' "$rows" | grep -c . || true)
+
+if [ "$count" -eq 0 ]; then
+  fail "no open release PR.
+      Nothing has landed since the last tag that release-please puts in a
+      changelog, so there is nothing to release. Land a feat/fix/perf/revert/docs
+      change first, or check that the Publish and Release workflow is running."
+fi
+if [ "$count" -gt 1 ]; then
+  fail "$count open release PRs, expected exactly one:
+$rows"
+fi
+IFS=$(printf '\t') read -r pr_number head_ref pr_title <<EOF
+$rows
+EOF
+pass "one open release PR: #$pr_number ($pr_title)"
+
+# release-please reads the version to tag from the PR title, while npm publishes
+# whatever package.json says. If those disagree the tag and the published package
+# describe different releases, so check all three sources against each other.
+# The version is the last field, not everything after 'release': release-please
+# writes the component into the title as 'release <component> X.Y.Z' whenever it
+# is configured to tag with one.
+title_version=${pr_title##* }
+case $title_version in
+[0-9]*.[0-9]*.[0-9]*) ;;
+*) fail "cannot read a version from PR title '$pr_title'." ;;
+esac
+pkg_version=$(gh api "repos/$repo/contents/package.json?ref=$head_ref" \
+  -H "Accept: application/vnd.github.raw" --jq .version)
+manifest_version=$(gh api "repos/$repo/contents/.release-please-manifest.json?ref=$head_ref" \
+  -H "Accept: application/vnd.github.raw" --jq '."."')
+
+if [ "$title_version" != "$pkg_version" ] || [ "$title_version" != "$manifest_version" ]; then
+  fail "version mismatch on #$pr_number:
+      PR title                      $title_version
+      package.json                  $pkg_version
+      .release-please-manifest.json $manifest_version"
+fi
+pass "version agrees across PR title, package.json and manifest: $title_version"
+
+# The tag comes from the config, not from the PR title. With
+# include-component-in-tag left on, release-please tags <component>-vX.Y.Z, which
+# breaks the vX.Y.Z scheme the rest of this script and docs/RELEASES.md rely on,
+# and makes it rewrite the whole history into the changelog because no tag under
+# that scheme exists yet. The compare link it writes into the PR body names the
+# tags it is going to use, so check those rather than trusting the config.
+compare_tag=$(gh pr view "$pr_number" --repo "$repo" --json body --jq '
+  .body | capture("/compare/[^)]*[.][.][.](?<to>[^)\\s]+)").to // ""' 2>/dev/null || true)
+case $compare_tag in
+"" | "v$title_version") ;;
+*) fail "release-please is going to tag '$compare_tag', not 'v$title_version'.
+      Every previous release is tagged vX.Y.Z, and the changelog for #$pr_number
+      covers the whole history rather than just this release, because no tag
+      under that scheme exists. Set 'include-component-in-tag': false in
+      release-please-config.json, then let it rewrite the release PR." ;;
+esac
+
+if gh release view "v$title_version" --repo "$repo" >/dev/null 2>&1; then
+  fail "tag v$title_version already exists. Merging would try to release it twice."
+fi
+pass "tag v$title_version does not exist yet"
+
+build=$(gh pr view "$pr_number" --repo "$repo" --json statusCheckRollup --jq '
+  [.statusCheckRollup[]? | select(.name == "Build")]
+  | if length == 0 then "MISSING" else (.[0].conclusion // .[0].status // "PENDING") end')
+[ "$build" = "SUCCESS" ] ||
+  fail "required check 'Build' is $build on #$pr_number, expected SUCCESS."
+pass "required check 'Build' passed"
+
+cat <<EOF
+
+Ready to release $title_version.
+
+  gh pr merge $pr_number --squash
+
+Merging tags v$title_version, publishes to npm and updates the agent registry.
+EOF

src/acp-subagents.ts

@@ -0,0 +1,124 @@
+import type {
+  ClientCapabilities,
+  SessionCapabilities,
+  SessionNotification,
+} from "@agentclientprotocol/sdk";
+import {
+  AIR_NATIVE_SUBAGENT_SESSIONS_CAPABILITY,
+  clientSupportsAirCapability,
+} from "./air-extension.js";
+
+export { AIR_NATIVE_SUBAGENT_SESSIONS_CAPABILITY } from "./air-extension.js";
+
+/**
+ * Temporary typed surface for agentclientprotocol/agent-client-protocol#1992.
+ *
+ * The wire contract is already defined by the ACP draft, but the published
+ * TypeScript SDK does not contain it yet. Keep the compatibility boundary in
+ * this file so it can be replaced by SDK exports without changing lifecycle
+ * code when the draft ships.
+ */
+export type SubagentSessionCapabilities = {
+  cancel?: boolean;
+  close?: boolean;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type SubagentSpawnedUpdate = {
+  sessionUpdate: "subagent_spawned";
+  subagentSessionId: string;
+  name: string;
+  task: string;
+  /**
+   * Adapter extension: the exact prompt of the subagent. A client can show it
+   * as the first user message of the subagent session. It is absent when the
+   * adapter does not know the prompt.
+   */
+  prompt?: string;
+  capabilities: SubagentSessionCapabilities;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type SubagentState = "completed" | "failed" | "cancelled" | "disconnected";
+
+export type SubagentStateUpdate = {
+  sessionUpdate: "subagent_state_update";
+  subagentSessionId: string;
+  state: SubagentState;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type AsyncTaskState = "running" | "paused" | "completed" | "failed" | "stopped";
+
+export type AsyncTaskSpawnedUpdate = {
+  sessionUpdate: "async_task_spawned";
+  asyncTaskId: string;
+  name: string;
+  taskType: string;
+  description: string;
+  showInTranscript: boolean;
+  canStop: boolean;
+  outputFilePath?: string;
+  toolCallId?: string;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type AsyncTaskProgressUpdate = {
+  sessionUpdate: "async_task_progress";
+  asyncTaskId: string;
+  description?: string;
+  summary?: string;
+  lastToolName?: string;
+  usage?: { totalTokens: number; toolUses: number; durationMs: number };
+  /** Latest durable task log path. May arrive after spawn. */
+  outputFilePath?: string;
+  /** Originating tool call, when correlation becomes known after spawn. */
+  toolCallId?: string;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type AsyncTaskStateUpdate = {
+  sessionUpdate: "async_task_state_update";
+  asyncTaskId: string;
+  state: AsyncTaskState;
+  summary?: string;
+  /** Latest durable task log path, including terminal-only SDK reports. */
+  outputFilePath?: string;
+  /** Originating tool call, including terminal-only late correlation. */
+  toolCallId?: string;
+  _meta?: Record<string, unknown> | null;
+};
+
+export type AcpSessionUpdate =
+  | SessionNotification["update"]
+  | SubagentSpawnedUpdate
+  | SubagentStateUpdate
+  | AsyncTaskSpawnedUpdate
+  | AsyncTaskProgressUpdate
+  | AsyncTaskStateUpdate;
+
+export type AcpSessionNotification = Omit<SessionNotification, "update"> & {
+  update: AcpSessionUpdate;
+};
+
+export type SubagentAwareSessionCapabilities = SessionCapabilities & {
+  subagents?: Record<string, never>;
+};
+
+export function clientSupportsSubagents(capabilities?: ClientCapabilities | null): boolean {
+  const subagents = (
+    capabilities as (ClientCapabilities & { subagents?: unknown }) | null | undefined
+  )?.subagents;
+  if (typeof subagents === "object" && subagents !== null && !Array.isArray(subagents)) {
+    return true;
+  }
+
+  return clientSupportsAirCapability(capabilities, AIR_NATIVE_SUBAGENT_SESSIONS_CAPABILITY);
+}
+
+/** The only cast needed until the TypeScript SDK publishes PR #1992. */
+export function asSdkSessionNotification(
+  notification: AcpSessionNotification,
+): SessionNotification {
+  return notification as SessionNotification;
+}

src/air-extension.ts

@@ -0,0 +1,119 @@
+export const AIR_NATIVE_SUBAGENT_SESSIONS_CAPABILITY = "nativeSubagentSessions";
+export const AIR_ASYNC_TASKS_CAPABILITY = "asyncTasks";
+export const AIR_SESSION_FAILURE_CAPABILITY = "sessionFailure";
+export const AIR_RECOMMENDED_CONFIG_VALUE_CAPABILITY = "recommendedValue";
+export const AIR_DIFF_PATCH_CAPABILITY = "diffPatch";
+/** AIR renders `rawInput` itself and needs no display copy of the input. */
+export const AIR_RAW_INPUT_RENDERING_CAPABILITY = "rawInputRendering";
+/**
+ * The plan of an ExitPlanMode is a file. `rawInput.planFilePath` names the
+ * file, and AIR reads the plan from it.
+ */
+export const AIR_PLAN_FILE_CAPABILITY = "planFile";
+
+/** The `_meta.jetbrains.air` keys that the ACP tool call contract defines. */
+export const AIR_COMMAND_TITLE_KEY = "commandTitle";
+export const AIR_SUBAGENT_KEY = "subagent";
+export const AIR_SKILL_KEY = "skill";
+export const AIR_CONTEXT_COMPACTION_KEY = "contextCompaction";
+export const AIR_GOAL_KEY = "goal";
+export const AIR_KIND_KEY = "kind";
+export const AIR_PERMISSION_KEY = "permission";
+export const AIR_CUSTOM_ANSWER_KEY = "customAnswer";
+
+const JETBRAINS_META_KEY = "jetbrains";
+const AIR_META_KEY = "air";
+const AIR_EXTENSION_VERSION_KEY = "version";
+const AIR_EXTENSION_CAPABILITIES_KEY = "capabilities";
+const AIR_EXTENSION_VERSION = 1;
+
+/** The capability list this side advertises, as its own `_meta` object. */
+export function airCapabilityMeta(...capabilities: string[]) {
+  return withAirMeta(undefined, AIR_EXTENSION_CAPABILITIES_KEY, capabilities);
+}
+
+/**
+ * Merges one AIR extension payload into an existing `_meta`.
+ *
+ * Every other namespace is preserved: an update can carry both agent-native
+ * `claudeCode` metadata and an AIR payload, and two AIR payloads can share the
+ * same `air` object. Pass `undefined` to build a fresh `_meta`.
+ */
+export function withAirMeta(
+  meta: Record<string, unknown> | null | undefined,
+  capability: string,
+  payload: unknown,
+): Record<string, unknown> {
+  const jetbrains = asRecord(meta?.[JETBRAINS_META_KEY]);
+  const air = asRecord(jetbrains[AIR_META_KEY]);
+  return {
+    ...meta,
+    [JETBRAINS_META_KEY]: {
+      ...jetbrains,
+      [AIR_META_KEY]: {
+        ...air,
+        [AIR_EXTENSION_VERSION_KEY]: AIR_EXTENSION_VERSION,
+        [capability]: payload,
+      },
+    },
+  };
+}
+
+/**
+ * Whether the client is JetBrains AIR: it declared `_meta.jetbrains.air` in
+ * its capabilities.
+ *
+ * Only AIR gets the AIR extensions of `docs/air-extensions.md`. Every other
+ * client, Zed too, gets the fields and the upstream `_meta` keys of the
+ * upstream adapter, and no key that exists only for AIR.
+ */
+export function isAirClient(capabilities: unknown): boolean {
+  return airExtensionMeta(asRecord(capabilities)._meta) !== undefined;
+}
+
+/**
+ * The `_meta` of an AIR client with one more AIR payload, or undefined for
+ * every other client: a client that is not AIR gets no AIR key.
+ */
+export function airOnlyMeta(
+  airClient: boolean,
+  capability: string,
+  payload: unknown,
+  meta?: Record<string, unknown> | null,
+): Record<string, unknown> | undefined {
+  return airClient ? withAirMeta(meta, capability, payload) : (meta ?? undefined);
+}
+
+/** The `air` object inside a `_meta`, or undefined when the peer sent no AIR extension. */
+export function airExtensionMeta(meta: unknown): Record<string, unknown> | undefined {
+  const air = asRecord(asRecord(meta)[JETBRAINS_META_KEY])[AIR_META_KEY];
+  return air && typeof air === "object" && !Array.isArray(air)
+    ? (air as Record<string, unknown>)
+    : undefined;
+}
+
+/**
+ * Whether the peer advertised `capability`.
+ *
+ * Takes `unknown` because every caller is reading wire data: an ACP
+ * `ClientCapabilities`, or a bag whose `_meta` was never validated.
+ */
+export function clientSupportsAirCapability(capabilities: unknown, capability: string): boolean {
+  const air = airExtensionMeta(asRecord(capabilities)._meta);
+  const version = air?.[AIR_EXTENSION_VERSION_KEY];
+  const advertised = air?.[AIR_EXTENSION_CAPABILITIES_KEY];
+  return (
+    typeof version === "number" &&
+    Number.isFinite(version) &&
+    Number.isInteger(version) &&
+    version >= AIR_EXTENSION_VERSION &&
+    Array.isArray(advertised) &&
+    advertised.includes(capability)
+  );
+}
+
+function asRecord(value: unknown): Record<string, unknown> {
+  return value && typeof value === "object" && !Array.isArray(value)
+    ? (value as Record<string, unknown>)
+    : {};
+}

src/async-tasks.ts

@@ -0,0 +1,893 @@
+import type { ClientCapabilities } from "@agentclientprotocol/sdk";
+import type { AcpSessionNotification, AsyncTaskState } from "./acp-subagents.js";
+import { AIR_ASYNC_TASKS_CAPABILITY, clientSupportsAirCapability } from "./air-extension.js";
+import { noticeOrTranscriptUpdate } from "./session-notices.js";
+
+type Publish = (notification: AcpSessionNotification) => Promise<void>;
+/** Moves an update to its owner session, or drops it with `null`. */
+type Route = (notification: AcpSessionNotification) => AcpSessionNotification | null;
+type TerminalSource = "event" | "level" | "shutdown";
+
+type AsyncTask = {
+  id: string;
+  name: string;
+  taskType: string;
+  description: string;
+  showInTranscript: boolean;
+  outputFilePath?: string;
+  toolCallId?: string;
+  /**
+   * The route to the session of the tool call that started the task. The
+   * spawn sets it, so every update of the task goes to one session. A task
+   * without a route stays in the root session.
+   */
+  route?: Route;
+  announced: boolean;
+  /**
+   * Whether the spawn waits for the tool call id. The updates of a held task
+   * wait in {@link AsyncTask.deferred} and follow the spawn in order.
+   */
+  held: boolean;
+  deferred: (() => Promise<void>)[];
+  ignored: boolean;
+  startedObserved: boolean;
+  panelOnlyRecovery: boolean;
+  stopping: boolean;
+  stopAnnounced: boolean;
+  state: AsyncTaskState;
+  terminalSummary?: string;
+  terminalSource?: TerminalSource;
+  /** The optional fields that the client holds now, as JSON. */
+  published: Map<string, string>;
+};
+
+type TaskIdentity = { taskId?: unknown; task_id?: unknown };
+
+export type AsyncTaskStarted = TaskIdentity & {
+  taskType?: unknown;
+  task_type?: unknown;
+  description?: unknown;
+  subagentType?: unknown;
+  subagent_type?: unknown;
+  isBackgrounded?: unknown;
+  is_backgrounded?: unknown;
+  workflowName?: unknown;
+  workflow_name?: unknown;
+  skipTranscript?: unknown;
+  skip_transcript?: unknown;
+  outputFilePath?: unknown;
+  output_file?: unknown;
+  toolCallId?: unknown;
+  tool_use_id?: unknown;
+};
+
+export type AsyncTaskUpdated = TaskIdentity & { patch?: TaskPatch };
+
+type TaskPatch = {
+  status?: unknown;
+  description?: unknown;
+  isBackgrounded?: unknown;
+  is_backgrounded?: unknown;
+  error?: unknown;
+  outputFilePath?: unknown;
+  output_file?: unknown;
+};
+
+export type AsyncTaskNotification = TaskIdentity & {
+  status?: unknown;
+  toolCallId?: unknown;
+  tool_use_id?: unknown;
+  summary?: unknown;
+  outputFilePath?: unknown;
+  output_file?: unknown;
+};
+
+type TaskProgress = TaskIdentity & {
+  description?: unknown;
+  toolCallId?: unknown;
+  tool_use_id?: unknown;
+  summary?: unknown;
+  lastToolName?: unknown;
+  last_tool_name?: unknown;
+  usage?: unknown;
+  outputFilePath?: unknown;
+  output_file?: unknown;
+};
+
+type BackgroundTaskLevel = TaskIdentity & {
+  taskType?: unknown;
+  task_type?: unknown;
+  description?: unknown;
+};
+
+export function clientSupportsAsyncTasks(capabilities?: ClientCapabilities | null): boolean {
+  return clientSupportsAirCapability(capabilities, AIR_ASYNC_TASKS_CAPABILITY);
+}
+
+/** Publishes Claude's non-agent background work as a separate AIR task lifecycle. */
+export class AsyncTaskRuntime {
+  /**
+   * One registry owns both active tasks and terminal tombstones. Keeping an
+   * unannounced terminal record is intentional: the Bash result proving that
+   * a command was backgrounded can arrive after its terminal SDK edge.
+   */
+  private readonly tasks = new Map<string, AsyncTask>();
+
+  constructor(
+    readonly enabled: boolean,
+    private readonly sessionId: string,
+    private readonly publish: Publish,
+    /** `notices`: the client can present `notice` updates, so the stop
+     *  acknowledgement need not be a transcript line. `routeOf`: the route of
+     *  the tasks that a tool call in another session started, for example in
+     *  a native subagent session. */
+    private readonly options: {
+      notices?: boolean;
+      routeOf?: (toolCallId: string) => Route | undefined;
+    } = {},
+  ) {}
+
+  async taskStarted(message: AsyncTaskStarted): Promise<void> {
+    if (!this.enabled) return;
+    const taskId = taskIdOf(message);
+    if (!taskId) return;
+    const task = this.task(taskId);
+    if (isSubagentTask(message)) {
+      task.ignored = true;
+      return;
+    }
+
+    const previousOutputFilePath = task.outputFilePath;
+    const previousToolCallId = task.toolCallId;
+    const wasAnnounced = task.announced;
+    this.mergeStarted(task, message);
+    if (
+      isBackgroundTask(
+        field(message, "isBackgrounded", "is_backgrounded"),
+        field(message, "taskType", "task_type"),
+      ) ||
+      task.held
+    ) {
+      await this.announce(task);
+    }
+    if (
+      wasAnnounced &&
+      (task.outputFilePath !== previousOutputFilePath || task.toolCallId !== previousToolCallId)
+    ) {
+      await this.publishMetadata(task);
+    }
+  }
+
+  async taskBackgrounded(message: AsyncTaskStarted): Promise<void> {
+    if (!this.enabled) return;
+    const taskId = taskIdOf(message);
+    if (!taskId) return;
+    const task = this.task(taskId);
+    if (isSubagentTask(message)) {
+      task.ignored = true;
+      return;
+    }
+
+    const previousOutputFilePath = task.outputFilePath;
+    const previousToolCallId = task.toolCallId;
+    const wasAnnounced = task.announced;
+    this.mergeStarted(task, message);
+    await this.announce(task);
+    if (
+      wasAnnounced &&
+      (task.outputFilePath !== previousOutputFilePath || task.toolCallId !== previousToolCallId)
+    ) {
+      await this.publishMetadata(task);
+    }
+  }
+
+  async taskUpdated(message: AsyncTaskUpdated): Promise<void>;
+  async taskUpdated(taskId: string, patch: TaskPatch): Promise<void>;
+  async taskUpdated(taskOrId: string | AsyncTaskUpdated, legacyPatch?: TaskPatch): Promise<void> {
+    if (!this.enabled) return;
+    const taskId = typeof taskOrId === "string" ? nonBlankString(taskOrId) : taskIdOf(taskOrId);
+    const patch = typeof taskOrId === "string" ? legacyPatch : taskOrId.patch;
+    if (!taskId || !patch) return;
+
+    const task = this.task(taskId);
+    const previousOutputFilePath = task.outputFilePath;
+    this.mergePatch(task, patch);
+    if (field(patch, "isBackgrounded", "is_backgrounded") === true) {
+      await this.announce(task);
+    }
+
+    const state = taskState(patch.status);
+    if (!state) {
+      if (task.announced && task.outputFilePath !== previousOutputFilePath) {
+        await this.publishMetadata(task);
+      }
+      return;
+    }
+
+    if (state === "running" || state === "paused") {
+      if (isTerminal(task.state)) {
+        if (task.announced && task.outputFilePath !== previousOutputFilePath) {
+          await this.publishMetadata(task);
+        }
+        return;
+      }
+      if (task.state !== state) {
+        task.state = state;
+        const error = nonBlankString(patch.error);
+        await this.whenAnnounced(task, () => this.publishState(task, state, error));
+      } else if (task.announced && task.outputFilePath !== previousOutputFilePath) {
+        await this.publishMetadata(task);
+      }
+      return;
+    }
+
+    await this.finish(task, state, nonBlankString(patch.error), "event");
+  }
+
+  async taskProgress(message: TaskProgress): Promise<void> {
+    if (!this.enabled) return;
+    const taskId = taskIdOf(message);
+    if (!taskId) return;
+    const task = this.tasks.get(taskId);
+    if (!task || task.ignored || !(task.announced || task.held)) return;
+
+    const previousOutputFilePath = task.outputFilePath;
+    const previousToolCallId = task.toolCallId;
+    this.mergeOutputFilePath(task, message);
+    this.mergeToolCallId(task, message);
+    const outputChanged = task.outputFilePath !== previousOutputFilePath;
+    if (isTerminal(task.state)) {
+      if (outputChanged) await this.publishMetadata(task);
+      return;
+    }
+
+    const usage = taskUsage(message.usage);
+    const description = nonBlankString(message.description);
+    const summary = nonBlankString(message.summary);
+    const lastToolName = nonBlankString(field(message, "lastToolName", "last_tool_name"));
+    const progress = {
+      ...(description ? { description } : {}),
+      ...(summary ? { summary } : {}),
+      ...(lastToolName ? { lastToolName } : {}),
+      ...(usage ? { usage } : {}),
+      ...(outputChanged && task.outputFilePath ? { outputFilePath: task.outputFilePath } : {}),
+      ...(task.toolCallId !== previousToolCallId && task.toolCallId
+        ? { toolCallId: task.toolCallId }
+        : {}),
+    };
+    await this.whenAnnounced(task, () => this.publishProgress(task, progress));
+    // The progress brought the tool call id of a held task: send the spawn,
+    // then the progress beats that waited for it.
+    if (task.held && task.toolCallId) await this.announce(task);
+  }
+
+  async taskNotification(message: AsyncTaskNotification): Promise<void>;
+  async taskNotification(
+    taskId: string,
+    status: unknown,
+    summary?: unknown,
+    outputFilePath?: unknown,
+  ): Promise<void>;
+  async taskNotification(
+    taskOrId: string | AsyncTaskNotification,
+    legacyStatus?: unknown,
+    legacySummary?: unknown,
+    legacyOutputFilePath?: unknown,
+  ): Promise<void> {
+    if (!this.enabled) return;
+    const message: AsyncTaskNotification =
+      typeof taskOrId === "string"
+        ? {
+            taskId: taskOrId,
+            status: legacyStatus,
+            summary: legacySummary,
+            outputFilePath: legacyOutputFilePath,
+          }
+        : taskOrId;
+    const taskId = taskIdOf(message);
+    const state = taskState(message.status);
+    if (!taskId || !state || state === "running" || state === "paused") return;
+
+    const task = this.task(taskId);
+    const wasTerminal = isTerminal(task.state);
+    const correctsLevelState = wasTerminal && task.terminalSource === "level";
+    const previousOutputFilePath = task.outputFilePath;
+    this.mergeOutputFilePath(task, message);
+    this.mergeToolCallId(task, message);
+    await this.finish(task, state, nonBlankString(message.summary), "event");
+    if (
+      wasTerminal &&
+      !correctsLevelState &&
+      task.announced &&
+      task.outputFilePath !== previousOutputFilePath
+    ) {
+      await this.publishMetadata(task);
+    }
+  }
+
+  /**
+   * Reconciles the SDK's replace-semantics background task level. It does not
+   * create unknown tasks because this level normally precedes task_started and
+   * carries no tool-call attribution. It can, however, promote a known
+   * foreground task and terminate an announced task whose edge was lost.
+   */
+  async backgroundTasksChanged(
+    tasksOrMessage: readonly BackgroundTaskLevel[] | { tasks?: unknown },
+  ): Promise<void> {
+    if (!this.enabled) return;
+    const value = Array.isArray(tasksOrMessage)
+      ? tasksOrMessage
+      : isRecord(tasksOrMessage)
+        ? tasksOrMessage.tasks
+        : undefined;
+    if (!Array.isArray(value)) return;
+
+    const live = new Set<string>();
+    for (const item of value) {
+      if (!isRecord(item)) continue;
+      const taskId = taskIdOf(item);
+      if (!taskId) continue;
+      live.add(taskId);
+      const task = this.task(taskId);
+      if (task.ignored || isTerminal(task.state)) continue;
+      if (field(item, "taskType", "task_type") === "local_agent") {
+        task.ignored = true;
+        continue;
+      }
+      if (!task.startedObserved) {
+        // The replace-level proves liveness but carries neither transcript
+        // policy nor full identity. Recover it for the Async Tasks panel only;
+        // creating a transcript card here would be irreversible if a late
+        // task_started says skip_transcript=true.
+        task.panelOnlyRecovery = true;
+        task.showInTranscript = false;
+      }
+      this.mergeLevel(task, item);
+      await this.announce(task);
+    }
+
+    for (const task of this.tasks.values()) {
+      if (
+        (task.announced || task.held) &&
+        !task.ignored &&
+        !isTerminal(task.state) &&
+        !live.has(task.id)
+      ) {
+        // This replace-semantics level is itself the authoritative liveness
+        // boundary. Close immediately so a lost terminal edge cannot leave a
+        // permanent running card; a following task_notification may correct
+        // the best-effort stopped state to completed/failed.
+        await this.finish(task, "stopped", undefined, "level");
+      }
+    }
+  }
+
+  async finishAll(state: Extract<AsyncTaskState, "failed" | "stopped">): Promise<void> {
+    const errors: unknown[] = [];
+    for (const task of this.tasks.values()) {
+      if ((task.announced || task.held) && !task.ignored && !isTerminal(task.state)) {
+        try {
+          await this.finish(task, state, undefined, "shutdown");
+        } catch (error) {
+          errors.push(error);
+        }
+      }
+    }
+    if (errors.length === 1) throw errors[0];
+    if (errors.length > 1) throw new AggregateError(errors, "Failed to finish async tasks");
+  }
+
+  canStop(taskId: string): boolean {
+    const task = this.tasks.get(taskId);
+    return task?.announced === true && !task.ignored && !task.stopping && !isTerminal(task.state);
+  }
+
+  claimStop(taskId: string): boolean {
+    if (!this.canStop(taskId)) return false;
+    this.tasks.get(taskId)!.stopping = true;
+    return true;
+  }
+
+  releaseStop(taskId: string): void {
+    const task = this.tasks.get(taskId);
+    if (task && !isTerminal(task.state)) task.stopping = false;
+  }
+
+  async taskStopped(taskId: string): Promise<void> {
+    const task = this.tasks.get(taskId);
+    if (!task || !task.announced || task.ignored || task.stopAnnounced) return;
+    task.stopAnnounced = true;
+    // No terminal summary: a stopped task leaves the Async Tasks panel at once,
+    // so anything said there is said to nobody.
+    await this.finish(task, "stopped", undefined, "event");
+    // This acknowledgement is the only one the user gets -- the SDK injects
+    // nothing into the model's context for a stopped shell task. A client on
+    // the notice contract shows it as a live `notice`; otherwise the
+    // transcript is where it has to land.
+    //
+    // Terminal state deliberately does not gate this. The SDK's own
+    // `task_notification` routinely wins the race against the `stopTask`
+    // response that brought us here, so by now the task is usually already
+    // terminal: gating on that would silence the very stop the user asked for.
+    // `stopAnnounced` is what keeps this to one line per task.
+    //
+    // `showInTranscript` does not gate it either: that flag decides whether the
+    // task owns a transcript *card* (a background Bash task is already drawn as
+    // its tool call), not whether the agent may answer a direct user action.
+    await this.send(
+      task,
+      noticeOrTranscriptUpdate(
+        { severity: "info", title: "Task stopped by user", description: `${task.name}.` },
+        this.options.notices ?? false,
+      ),
+    );
+  }
+
+  /**
+   * Sends the spawn of each held task without a tool call id. The prompt
+   * result ends the model turn, and the result of the tool call that started a
+   * task comes before it. So a held task is never held for longer than one turn.
+   */
+  async releaseHeld(): Promise<void> {
+    if (!this.enabled) return;
+    for (const task of this.tasks.values()) {
+      if (task.held) await this.announce(task, { withoutToolCall: true });
+    }
+  }
+
+  clear(): void {
+    this.tasks.clear();
+  }
+
+  private task(taskId: string): AsyncTask {
+    let task = this.tasks.get(taskId);
+    if (task) return task;
+    task = {
+      id: taskId,
+      name: "Background task",
+      taskType: "task",
+      description: "Background task",
+      showInTranscript: true,
+      announced: false,
+      held: false,
+      deferred: [],
+      ignored: false,
+      startedObserved: false,
+      panelOnlyRecovery: false,
+      stopping: false,
+      stopAnnounced: false,
+      state: "running",
+      published: new Map(),
+    };
+    this.tasks.set(taskId, task);
+    return task;
+  }
+
+  private mergeStarted(task: AsyncTask, message: AsyncTaskStarted): void {
+    task.startedObserved = true;
+    const rawTaskType = field(message, "taskType", "task_type");
+    if (rawTaskType !== undefined) task.taskType = friendlyTaskType(rawTaskType);
+    const description = nonBlankString(message.description);
+    if (description) task.description = description;
+    else if (task.description === "Background task")
+      task.description = defaultDescription(task.taskType);
+    task.name = nonBlankString(field(message, "workflowName", "workflow_name")) ?? task.description;
+    const skipTranscript = field(message, "skipTranscript", "skip_transcript");
+    if (task.panelOnlyRecovery) {
+      // A level-only recovery was already announced without a transcript
+      // entry. Keep that decision monotonic: a late task_started can enrich
+      // the panel, but cannot retroactively create or mutate transcript UI.
+      task.showInTranscript = false;
+    } else if (skipTranscript !== undefined) {
+      task.showInTranscript = skipTranscript !== true;
+    }
+    this.mergeOutputFilePath(task, message);
+    const toolCallId = nonBlankString(field(message, "toolCallId", "tool_use_id"));
+    if (toolCallId) task.toolCallId = toolCallId;
+  }
+
+  /** Keeps the first tool call id that a later SDK message brings. */
+  private mergeToolCallId(
+    task: AsyncTask,
+    value: { toolCallId?: unknown; tool_use_id?: unknown },
+  ): void {
+    task.toolCallId ??= nonBlankString(field(value, "toolCallId", "tool_use_id"));
+  }
+
+  /** Sends an update of an announced task. A held task sends it after its spawn. */
+  private async whenAnnounced(task: AsyncTask, send: () => Promise<void>): Promise<void> {
+    if (task.announced) await send();
+    else if (task.held) task.deferred.push(send);
+  }
+
+  private mergePatch(task: AsyncTask, patch: TaskPatch): void {
+    const description = nonBlankString(patch.description);
+    if (description) {
+      task.description = description;
+      task.name = description;
+    }
+    this.mergeOutputFilePath(task, patch);
+  }
+
+  private mergeLevel(task: AsyncTask, level: BackgroundTaskLevel): void {
+    const rawTaskType = field(level, "taskType", "task_type");
+    if (rawTaskType !== undefined) task.taskType = friendlyTaskType(rawTaskType);
+    const description = nonBlankString(level.description);
+    if (description) {
+      task.description = description;
+      task.name = description;
+    }
+  }
+
+  private mergeOutputFilePath(
+    task: AsyncTask,
+    value: { outputFilePath?: unknown; output_file?: unknown },
+  ): void {
+    const outputFilePath = nonBlankString(field(value, "outputFilePath", "output_file"));
+    if (outputFilePath) task.outputFilePath = outputFilePath;
+  }
+
+  /**
+   * Sends the spawn of the task. The spawn names the tool call that started the
+   * task, so it waits for the tool call id: the task is held until the id
+   * arrives. The id comes as `tool_use_id` of the SDK `task_started`,
+   * `task_progress`, or `task_notification`, or from the Bash result of a
+   * backgrounded command. A held task gets its spawn without the id when it
+   * ends first, or when the prompt result ends the model turn
+   * ({@link releaseHeld}). No guess by the command text binds a task.
+   */
+  private async announce(
+    task: AsyncTask,
+    options: { withoutToolCall?: boolean } = {},
+  ): Promise<void> {
+    if (task.announced || task.ignored) return;
+    if (!task.toolCallId && !options.withoutToolCall && !isTerminal(task.state)) {
+      task.held = true;
+      return;
+    }
+    if (task.toolCallId) task.route ??= this.options.routeOf?.(task.toolCallId);
+    await this.send(task, {
+      sessionUpdate: "async_task_spawned",
+      asyncTaskId: task.id,
+      name: task.name,
+      taskType: task.taskType,
+      description: task.description,
+      showInTranscript: task.showInTranscript,
+      canStop: true,
+      ...(task.outputFilePath ? { outputFilePath: task.outputFilePath } : {}),
+      ...(task.toolCallId ? { toolCallId: task.toolCallId } : {}),
+    });
+    task.announced = true;
+    task.held = false;
+    recordPublished(task, {
+      description: task.description,
+      outputFilePath: task.outputFilePath,
+      toolCallId: task.toolCallId,
+    });
+    for (const send of task.deferred.splice(0)) await send();
+    if (isTerminal(task.state)) {
+      await this.publishState(task, task.state, task.terminalSummary);
+    }
+  }
+
+  private async finish(
+    task: AsyncTask,
+    state: Extract<AsyncTaskState, "completed" | "failed" | "stopped">,
+    summary: string | undefined,
+    source: TerminalSource,
+  ): Promise<void> {
+    if (task.ignored) return;
+    if (isTerminal(task.state)) {
+      // A level event may precede the authoritative terminal edge. Correct its
+      // best-effort stopped state if that edge later arrives.
+      if (task.terminalSource !== "level" || source !== "event") return;
+    }
+    const previous = {
+      state: task.state,
+      terminalSummary: task.terminalSummary,
+      terminalSource: task.terminalSource,
+    };
+    task.state = state;
+    task.terminalSummary = summary;
+    task.terminalSource = source;
+    try {
+      if (task.announced) await this.publishState(task, state, summary);
+      // The task ended before its tool call id arrived. The spawn goes out now
+      // without the id, so the task still appears.
+      else if (task.held) await this.announce(task);
+    } catch (error) {
+      task.state = previous.state;
+      task.terminalSummary = previous.terminalSummary;
+      task.terminalSource = previous.terminalSource;
+      throw error;
+    }
+  }
+
+  private async publishMetadata(task: AsyncTask): Promise<void> {
+    if (task.outputFilePath || task.toolCallId) {
+      if (isTerminal(task.state)) {
+        await this.publishState(task, task.state, task.terminalSummary);
+      } else {
+        await this.publishProgress(task, {
+          ...(task.outputFilePath ? { outputFilePath: task.outputFilePath } : {}),
+          ...(task.toolCallId ? { toolCallId: task.toolCallId } : {}),
+        });
+      }
+    }
+  }
+
+  /**
+   * Publishes the progress fields that changed since the last report of the
+   * task. A beat with nothing new is not sent.
+   */
+  private async publishProgress(
+    task: AsyncTask,
+    update: {
+      description?: string;
+      summary?: string;
+      lastToolName?: string;
+      usage?: { totalTokens: number; toolUses: number; durationMs: number };
+      outputFilePath?: string;
+      toolCallId?: string;
+    },
+  ): Promise<void> {
+    const changed = changedFields(task, update);
+    if (Object.keys(changed).length === 0) return;
+    await this.send(task, {
+      sessionUpdate: "async_task_progress",
+      asyncTaskId: task.id,
+      ...changed,
+    });
+    recordPublished(task, changed);
+  }
+
+  /** Publishes a state, with the output path and the tool call only when they changed. */
+  private async publishState(
+    task: AsyncTask,
+    state: AsyncTaskState,
+    summary?: string,
+  ): Promise<void> {
+    const changed = changedFields(task, {
+      outputFilePath: task.outputFilePath,
+      toolCallId: task.toolCallId,
+    });
+    await this.send(task, {
+      sessionUpdate: "async_task_state_update",
+      asyncTaskId: task.id,
+      state,
+      ...(summary ? { summary } : {}),
+      ...changed,
+    });
+    recordPublished(task, changed);
+  }
+
+  /** Publishes an update of the task in the session that owns the task. */
+  private async send(task: AsyncTask, update: AcpSessionNotification["update"]): Promise<void> {
+    const notification: AcpSessionNotification = { sessionId: this.sessionId, update };
+    const routed = task.route ? task.route(notification) : notification;
+    if (routed) await this.publish(routed);
+  }
+}
+
+/**
+ * The fields whose value differs from what the client holds. An undefined
+ * value is not a field. The caller records the fields with
+ * {@link recordPublished} after the send succeeds, so a retry after a failed
+ * send carries them again.
+ */
+function changedFields<T extends Record<string, unknown>>(task: AsyncTask, fields: T): Partial<T> {
+  const changed: Partial<T> = {};
+  for (const [key, value] of Object.entries(fields)) {
+    if (value === undefined) continue;
+    if (task.published.get(key) === JSON.stringify(value)) continue;
+    (changed as Record<string, unknown>)[key] = value;
+  }
+  return changed;
+}
+
+/** Records the fields that the client holds now. An undefined value is not a field. */
+function recordPublished(task: AsyncTask, fields: Record<string, unknown>): void {
+  for (const [key, value] of Object.entries(fields)) {
+    if (value !== undefined) task.published.set(key, JSON.stringify(value));
+  }
+}
+
+/** Recovers background Bash lifecycle data exposed only on its tool result. */
+export function backgroundBashTaskFromToolResult(
+  content: unknown,
+  toolUseResult: unknown,
+  toolUses: Record<string, { name: string; input: unknown }>,
+): AsyncTaskStarted | undefined {
+  if (!Array.isArray(content)) return undefined;
+  const toolResults = content.flatMap(toolResultBlock);
+  const bashResults = toolResults.filter((result) => toolUses[result.toolUseId]?.name === "Bash");
+  if (bashResults.length === 0) return undefined;
+
+  const backgroundResults = structuredBackgroundResults(toolUseResult, toolUses);
+  const distinctTaskIds = new Set([
+    ...backgroundResults.map((result) => result.taskId),
+    ...bashResults
+      .map((result) => backgroundTaskIdFromText(result.content))
+      .filter((taskId): taskId is string => taskId !== undefined),
+  ]);
+  if (distinctTaskIds.size !== 1) return undefined;
+  const taskId = [...distinctTaskIds][0];
+  if (!taskId) return undefined;
+
+  const hintedToolUseIds = new Set(
+    backgroundResults
+      .filter((result) => result.taskId === taskId && result.toolUseId)
+      .map((result) => result.toolUseId!),
+  );
+  let matches: typeof bashResults;
+  if (hintedToolUseIds.size > 0) {
+    matches = bashResults.filter((result) => hintedToolUseIds.has(result.toolUseId));
+  } else {
+    const pathMatches = bashResults.filter(
+      (result) => asyncTaskOutputFilePath(result.content, taskId) !== undefined,
+    );
+    matches = pathMatches.length > 0 ? pathMatches : bashResults.length === 1 ? bashResults : [];
+  }
+  if (matches.length !== 1) return undefined;
+
+  const match = matches[0];
+  const toolUse = toolUses[match.toolUseId];
+  const input = isRecord(toolUse?.input) ? toolUse.input : undefined;
+  return {
+    taskId,
+    taskType: "local_bash",
+    description: nonBlankString(input?.command),
+    isBackgrounded: true,
+    outputFilePath: asyncTaskOutputFilePath(match.content, taskId),
+    toolCallId: match.toolUseId,
+  };
+}
+
+function backgroundTaskIdFromText(content: unknown): string | undefined {
+  const text = textContent(content);
+  if (!text) return undefined;
+  const marker = "Command running in background with ID: ";
+  const start = text.indexOf(marker);
+  if (start < 0) return undefined;
+  const valueStart = start + marker.length;
+  const valueEnd = text.indexOf(".", valueStart);
+  return valueEnd < 0 ? undefined : nonBlankString(text.slice(valueStart, valueEnd));
+}
+
+function structuredBackgroundResults(
+  value: unknown,
+  toolUses: Record<string, { name: string; input: unknown }>,
+  hintedToolUseId?: string,
+  seen = new Set<unknown>(),
+): { taskId: string; toolUseId?: string }[] {
+  if (typeof value !== "object" || value === null || seen.has(value)) return [];
+  seen.add(value);
+  if (Array.isArray(value)) {
+    return value.flatMap((item) =>
+      structuredBackgroundResults(item, toolUses, hintedToolUseId, seen),
+    );
+  }
+
+  const directTaskId = nonBlankString(field(value, "backgroundTaskId", "background_task_id"));
+  const directToolUseId =
+    nonBlankString(field(value, "toolUseId", "tool_use_id")) ?? hintedToolUseId;
+  const results: { taskId: string; toolUseId?: string }[] = directTaskId
+    ? [{ taskId: directTaskId, toolUseId: directToolUseId }]
+    : [];
+  for (const [key, child] of Object.entries(value)) {
+    if (key === "backgroundTaskId" || key === "background_task_id") continue;
+    results.push(
+      ...structuredBackgroundResults(child, toolUses, toolUses[key] ? key : directToolUseId, seen),
+    );
+  }
+  return results;
+}
+
+function toolResultBlock(value: unknown): { toolUseId: string; content?: unknown }[] {
+  if (!isRecord(value) || value.type !== "tool_result") return [];
+  const toolUseId = nonBlankString(field(value, "toolUseId", "tool_use_id"));
+  return toolUseId ? [{ toolUseId, content: value.content }] : [];
+}
+
+function asyncTaskOutputFilePath(content: unknown, taskId: string): string | undefined {
+  const text = textContent(content);
+  if (!text) return undefined;
+  const marker = "Output is being written to: ";
+  const start = text.indexOf(marker);
+  if (start < 0) return undefined;
+  const valueStart = start + marker.length;
+  const valueEnd = text.indexOf(". You will be notified", valueStart);
+  if (valueEnd < 0) return undefined;
+  const path = text.slice(valueStart, valueEnd).trim();
+  const expectedPosixSuffix = `/tasks/${taskId}.output`;
+  const expectedWindowsSuffix = `\\tasks\\${taskId}.output`;
+  return path.endsWith(expectedPosixSuffix) || path.endsWith(expectedWindowsSuffix)
+    ? path
+    : undefined;
+}
+
+function textContent(value: unknown): string | undefined {
+  if (typeof value === "string") return value;
+  if (Array.isArray(value)) {
+    const parts = value.map(textContent).filter((part): part is string => part !== undefined);
+    return parts.length > 0 ? parts.join("") : undefined;
+  }
+  if (!isRecord(value)) return undefined;
+  if (typeof value.text === "string") return value.text;
+  return value.content === value ? undefined : textContent(value.content);
+}
+
+function friendlyTaskType(value: unknown): string {
+  if (value === "local_bash") return "shell";
+  if (value === "local_workflow") return "workflow";
+  if (value === "local_monitor" || value === "mcp") return "monitor";
+  return nonBlankString(value) ?? "task";
+}
+
+function defaultDescription(taskType: string): string {
+  return taskType === "task" ? "Background task" : taskType[0].toUpperCase() + taskType.slice(1);
+}
+
+function isBackgroundTask(isBackgrounded: unknown, taskType: unknown): boolean {
+  if (isBackgrounded === true) return true;
+  if (isBackgrounded === false) return false;
+  return taskType !== "local_bash" && taskType !== "local_agent";
+}
+
+function isSubagentTask(message: AsyncTaskStarted): boolean {
+  return (
+    field(message, "subagentType", "subagent_type") !== undefined ||
+    field(message, "taskType", "task_type") === "local_agent"
+  );
+}
+
+function taskState(value: unknown): AsyncTaskState | undefined {
+  if (value === "pending" || value === "running") return "running";
+  if (value === "paused") return "paused";
+  if (value === "completed") return "completed";
+  if (value === "failed") return "failed";
+  if (value === "killed" || value === "cancelled" || value === "stopped") return "stopped";
+  return undefined;
+}
+
+function isTerminal(state: AsyncTaskState): state is "completed" | "failed" | "stopped" {
+  return state === "completed" || state === "failed" || state === "stopped";
+}
+
+function taskUsage(
+  value: unknown,
+): { totalTokens: number; toolUses: number; durationMs: number } | undefined {
+  if (!isRecord(value)) return undefined;
+  const totalTokens = numberField(value, "totalTokens", "total_tokens");
+  const toolUses = numberField(value, "toolUses", "tool_uses");
+  const durationMs = numberField(value, "durationMs", "duration_ms");
+  if (totalTokens === undefined || toolUses === undefined || durationMs === undefined)
+    return undefined;
+  return { totalTokens, toolUses, durationMs };
+}
+
+function taskIdOf(value: TaskIdentity): string | undefined {
+  return nonBlankString(field(value, "taskId", "task_id"));
+}
+
+function field(value: object, camelCase: string, snakeCase: string): unknown {
+  const record = value as Record<string, unknown>;
+  return record[camelCase] !== undefined ? record[camelCase] : record[snakeCase];
+}
+
+function numberField(
+  value: Record<string, unknown>,
+  camelCase: string,
+  snakeCase: string,
+): number | undefined {
+  const result = field(value, camelCase, snakeCase);
+  return typeof result === "number" ? result : undefined;
+}
+
+function nonBlankString(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim().length > 0 ? value.trim() : undefined;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+}

src/auth-status.ts

@@ -0,0 +1,337 @@
+/**
+ * `authStatus` — interim `_meta`-based ACP extension that reports which auth
+ * identity the agent process itself uses (Claude subscription, API key,
+ * gateway, external cloud credentials, or nothing).
+ *
+ * Push only. One carrier, connection-scoped (never per session): the
+ * notification `_auth/status_update` → `{authStatus}`. The client never asks;
+ * there is no request method. The empty `agentCapabilities._meta.authStatus`
+ * marker means "this agent pushes its identity", nothing more.
+ *
+ * The agent reads the identity at these moments:
+ * - `initialize`, with an asynchronous CLI probe. Nothing waits for it, and its
+ *   result is the first push of the connection;
+ * - a completed `authenticate` or a `logout`;
+ * - each `createSession`, from the session account. A refused session reports
+ *   too: the client must know which account was refused;
+ * - each turn the `--hide-claude-auth` guard checks. The guard reads the
+ *   account anyway, so this costs nothing;
+ * - the START of each user prompt, with an asynchronous CLI probe. This finds a
+ *   login or a logout done in another terminal, including the sign-in a client
+ *   performs after a refusal, because the retried prompt is a new prompt.
+ *   Nothing waits for it and the push goes out mid-turn if that is when the
+ *   read lands.
+ *
+ * A probe whose kind differs from a live session's account marks that session
+ * for recreation under `--hide-claude-auth`. The mark is a flag, consumed at
+ * the next turn boundary: a running turn is never interrupted. The probe judges
+ * nothing itself — the next turn runs a new `initialize`, and the creation
+ * guard decides on the account it reports.
+ *
+ * A read does not always cause a push. The agent sends `_auth/status_update`
+ * only when the payload is different from the last one it sent.
+ *
+ * "Cannot determine" is expressed by silence: an agent that cannot read its own
+ * identity pushes nothing, and the client shows "not reported". A known
+ * logged-out state is a payload of its own (`kind: "none"`), which is what
+ * distinguishes the two.
+ *
+ * Reporting only — there is no write path in v1. When the upstream RFD lands,
+ * the same payload moves from `_meta` to first-class fields and this module
+ * is retired.
+ */
+
+import type { AccountInfo } from "@anthropic-ai/claude-agent-sdk";
+
+/** Change notification, agent → client. Fire and forget: clients that do not
+ *  know the method drop it silently, so it is sent unconditionally. */
+export const AUTH_STATUS_UPDATE_METHOD = "_auth/status_update";
+
+/** Upper bound on one `claude auth status --json` run, so a hung CLI cannot
+ *  wedge every later probe that joins it. */
+export const AUTH_STATUS_PROBE_TIMEOUT_MS = 5000;
+
+export type AuthStatusKind = "account" | "api_key" | "gateway" | "external" | "none";
+
+export type AuthStatusAccount = {
+  email?: string;
+  organization?: string;
+  /** Vendor plan/license string, not normalized. */
+  plan?: string;
+};
+
+export type AuthStatus = {
+  kind: AuthStatusKind;
+  /** Human-readable and usable as a UI string on its own. The "type" line:
+   *  "Claude Max", "Anthropic API key", "AWS Bedrock". */
+  label: string;
+  /** Optional second line carrying the specifics (key source, gateway host, …).
+   *  Clients render it under `label`, falling back to `account.email`. */
+  detail?: string;
+  account?: AuthStatusAccount;
+  /** Vendor-namespaced extras, e.g. `{claudeCode: {...}}`. */
+  vendor?: Record<string, unknown>;
+};
+
+export type AuthStatusUpdateNotification = { authStatus: AuthStatus };
+
+/** Advertisement carried in `agentCapabilities._meta.authStatus`, never a
+ *  status payload: its mere presence means "this agent pushes its identity",
+ *  and it stays empty. Informational — a client that never saw it still
+ *  accepts `_auth/status_update`, because there is nothing to ask for. */
+export type AuthStatusCapability = Record<string, never>;
+
+export function authStatusCapability(): AuthStatusCapability {
+  return {};
+}
+
+/** Shape of `claude auth status --json`. Absent fields are omitted, not null,
+ *  and the logged-out case exits 1 while still printing valid JSON. */
+export type CliAuthStatus = {
+  loggedIn?: boolean;
+  authMethod?: string;
+  apiProvider?: string;
+  apiKeySource?: string;
+  email?: string;
+  orgId?: string;
+  orgName?: string;
+  subscriptionType?: string;
+};
+
+const NOT_LOGGED_IN: AuthStatus = {
+  kind: "none",
+  label: "Not logged in",
+};
+
+/** Display names for the non-firstParty backends, where auth lives outside the
+ *  agent (AWS credentials, gcloud ADC, …). */
+const EXTERNAL_PROVIDER_LABELS: Record<string, string> = {
+  bedrock: "AWS Bedrock",
+  vertex: "Google Vertex AI",
+  foundry: "Azure AI Foundry",
+  anthropicAws: "Anthropic on AWS",
+  anthropicGoogleCloud: "Anthropic on Google Cloud",
+  mantle: "Mantle",
+};
+
+export function notLoggedInAuthStatus(): AuthStatus {
+  return { ...NOT_LOGGED_IN };
+}
+
+/** ACP-level gateway auth (`authenticate` with `gateway`/`gateway-bedrock`).
+ *  The gateway owns the credentials, so it wins over anything the CLI reports. */
+export function gatewayAuthStatus(baseUrl?: string): AuthStatus {
+  let host: string | undefined;
+  if (baseUrl) {
+    try {
+      host = new URL(baseUrl).host;
+    } catch {
+      host = baseUrl;
+    }
+  }
+  return {
+    kind: "gateway",
+    label: "Custom model gateway",
+    ...(host ? { detail: host } : {}),
+  };
+}
+
+/**
+ * Does this `AccountInfo` say anything about the identity?
+ *
+ * The SDK always fills `apiProvider`, but the identity fields come from the
+ * claude.ai profile: with an `apiKeyHelper` and no subscription login the
+ * session reports `{apiProvider: "firstParty"}` and nothing else. That is "no
+ * information", not "logged out" — an empty read must never be mapped to
+ * `none`, or it destroys what the CLI probe already established.
+ *
+ * `tokenSource` is deliberately not a signal: the CLI sets it to the OAuth
+ * token's origin (`CLAUDE_CODE_OAUTH_TOKEN`,
+ * `CLAUDE_CODE_OAUTH_TOKEN_FILE_DESCRIPTOR`, …), never to a key source, so it
+ * cannot attribute a key and carries no plan of its own.
+ */
+export function accountInfoHasIdentitySignal(account: AccountInfo | undefined): boolean {
+  if (!account) return false;
+  return Boolean(
+    account.apiKeySource ||
+    account.subscriptionType ||
+    (account.apiProvider && account.apiProvider !== "firstParty"),
+  );
+}
+
+/** Session-time mapping from the SDK's `AccountInfo`, the richest source when
+ *  it is populated. Returns `undefined` when the account carries no identity
+ *  signal, so callers keep the status they already know. */
+export function fromAccountInfo(account: AccountInfo | undefined): AuthStatus | undefined {
+  if (!account || !accountInfoHasIdentitySignal(account)) {
+    return undefined;
+  }
+  return mapAuthFields({
+    apiProvider: account.apiProvider,
+    subscriptionType: account.subscriptionType,
+    apiKeySource: account.apiKeySource,
+    email: account.email,
+    organization: account.organization,
+  });
+}
+
+/** Pre-session mapping from `claude auth status --json` stdout. Returns
+ *  `undefined` when the output is not the expected JSON object, so callers can
+ *  report "not known" instead of guessing. */
+export function fromCliStatus(stdout: string): AuthStatus | undefined {
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(stdout);
+  } catch {
+    return undefined;
+  }
+  if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
+    return undefined;
+  }
+  const status = parsed as CliAuthStatus;
+  if (typeof status.loggedIn !== "boolean") {
+    return undefined;
+  }
+  // `loggedIn` tracks the claude.ai login only. On a 3P backend (Bedrock,
+  // Vertex, …) it is false while the credentials live outside the agent, so the
+  // backend must decide the kind before the logged-out shortcut runs.
+  const externalBackend = Boolean(status.apiProvider && status.apiProvider !== "firstParty");
+  if (!externalBackend && !status.loggedIn && !status.apiKeySource) {
+    return notLoggedInAuthStatus();
+  }
+  return mapAuthFields({
+    apiProvider: status.apiProvider,
+    subscriptionType: status.subscriptionType,
+    apiKeySource: status.apiKeySource,
+    email: status.email,
+    organization: status.orgName,
+  });
+}
+
+/** Single mapping table shared by both sources; see the `kind`/`label` table in
+ *  `extension-authstatus-meta.md`. Order matters: a 3P backend or a gateway
+ *  decides the kind before any firstParty identity fields are considered, and
+ *  an API key outranks a stored subscription login.
+ *
+ *  Both can be reported at once — an `apiKeyHelper` in settings.json next to a
+ *  claude.ai OAuth login yields `apiKeySource` AND `subscriptionType`. Claude
+ *  Code's authentication precedence puts `apiKeyHelper` above the `/login`
+ *  subscription, so the key is what actually pays for the turn and is what we
+ *  report. */
+function mapAuthFields(fields: {
+  apiProvider?: string;
+  subscriptionType?: string;
+  apiKeySource?: string;
+  email?: string;
+  organization?: string;
+}): AuthStatus {
+  const { apiProvider, subscriptionType, apiKeySource, email, organization } = fields;
+
+  if (apiProvider === "gateway") {
+    return gatewayAuthStatus();
+  }
+  if (apiProvider && apiProvider !== "firstParty") {
+    return {
+      kind: "external",
+      label: EXTERNAL_PROVIDER_LABELS[apiProvider] ?? apiProvider,
+    };
+  }
+  if (apiKeySource) {
+    return {
+      kind: "api_key",
+      label: "Anthropic API key",
+      // The source ("apiKeyHelper", "env", …) is the specifics line.
+      detail: apiKeySource,
+    };
+  }
+  if (subscriptionType) {
+    // `account.plan` keeps the raw vendor string; only the label is titled.
+    const account: AuthStatusAccount = { plan: subscriptionType };
+    if (email) account.email = email;
+    if (organization) account.organization = organization;
+    return {
+      kind: "account",
+      label: planLabel(subscriptionType),
+      // No detail: the client falls back to `account.email` for line 2.
+      account,
+    };
+  }
+  return notLoggedInAuthStatus();
+}
+
+/** Names the plan with exactly one "Claude". A newer CLI already reports
+ *  "Claude Max", an older one reports "max", and both must read "Claude Max".
+ *  Each word is title-cased; a word that already carries capitals is kept. */
+function planLabel(plan: string): string {
+  const titled = plan.replace(/\S+/g, (word) => word.charAt(0).toUpperCase() + word.slice(1));
+  return /^claude(\s|$)/i.test(plan) ? titled : `Claude ${titled}`;
+}
+
+/**
+ * Do two payloads describe the same login? Compared on the field that
+ * identifies each kind — the key source for `api_key`, the email for
+ * `account`, the kind alone for the rest, which carry no per-identity key.
+ */
+export function sameIdentity(a: AuthStatus, b: AuthStatus): boolean {
+  if (a.kind !== b.kind) {
+    return false;
+  }
+  switch (a.kind) {
+    case "api_key":
+      return a.detail === b.detail;
+    case "account":
+      return (a.account?.email ?? "") === (b.account?.email ?? "");
+    default:
+      return true;
+  }
+}
+
+/**
+ * Folds a fresh read into what is already known. Sources differ in richness for
+ * the very same login: the SDK's session `AccountInfo` can carry an
+ * organization the CLI probe omits. So when the read describes the same
+ * identity, its values win field by field but the fields it lacks are kept;
+ * when it describes a different identity, it replaces the old one wholesale.
+ */
+export function mergeAuthStatus(previous: AuthStatus | undefined, next: AuthStatus): AuthStatus {
+  if (!previous || !sameIdentity(previous, next)) {
+    return next;
+  }
+  const merged: AuthStatus = { ...next };
+  if (merged.detail === undefined && previous.detail !== undefined) {
+    merged.detail = previous.detail;
+  }
+  if (previous.account || next.account) {
+    merged.account = { ...previous.account, ...next.account };
+  }
+  if (merged.vendor === undefined && previous.vendor !== undefined) {
+    merged.vendor = previous.vendor;
+  }
+  return merged;
+}
+
+/**
+ * Do two payloads carry the same information? Unlike {@link sameIdentity},
+ * which asks "is this the same login", this compares every rendered field, so
+ * a richer read of one login is NOT the same. Callers use it to suppress a
+ * push that would tell the client nothing new.
+ *
+ * `a` undefined means "nothing reported yet", which never equals a payload.
+ */
+export function sameAuthStatus(a: AuthStatus | undefined, b: AuthStatus): boolean {
+  if (!a) {
+    return false;
+  }
+  return (
+    a.kind === b.kind &&
+    a.label === b.label &&
+    a.detail === b.detail &&
+    a.account?.email === b.account?.email &&
+    a.account?.organization === b.account?.organization &&
+    a.account?.plan === b.account?.plan &&
+    // Vendor extras are an open bag, so compare them structurally. Both sides
+    // are built by this module from the same key order, so a string compare is
+    // enough and costs nothing on the usual `undefined`/`undefined` pair.
+    JSON.stringify(a.vendor) === JSON.stringify(b.vendor)
+  );
+}

src/clear-context-coordinator.ts

@@ -0,0 +1,162 @@
+import type { NewSessionRequest, SessionConfigOption } from "@agentclientprotocol/sdk";
+import type {
+  EffortLevel,
+  Options,
+  PermissionMode,
+  SDKUserMessage,
+} from "@anthropic-ai/claude-agent-sdk";
+import { DEFAULT_MODEL_ID } from "./session-config-ids.js";
+
+export type ClearContextReset = {
+  toolUseId: string;
+  plan: string;
+  mode: PermissionMode;
+};
+
+type Usage = {
+  inputTokens: number;
+  outputTokens: number;
+  cachedReadTokens: number;
+  cachedWriteTokens: number;
+};
+
+export type ClearContextTurn = {
+  settled: boolean;
+  promptUuid: string;
+  carriedUsage?: Usage;
+  carriedModelUsage?: Record<string, Usage>;
+};
+
+/** The session state needed to replace Claude's private conversation without
+ * replacing the public ACP turn. Keeping this projection here makes the
+ * restart workflow independent from the agent's much larger Session record. */
+export type ClearContextSession<Turn extends ClearContextTurn = ClearContextTurn> = {
+  cwd: string;
+  creationParams?: NewSessionRequest;
+  accumulatedUsage: Usage;
+  accumulatedModelUsage?: Record<string, Usage>;
+  models: { currentModelId: string };
+  configOptions: SessionConfigOption[];
+  fastModeEnabled: boolean;
+  effortPinnedLevel?: string;
+  activeTurn?: Turn | null;
+  turnQueue?: Turn[];
+  pendingExitPlanContextReset?: ClearContextReset;
+  contextUsedTokens?: number;
+  input: { push(message: SDKUserMessage): unknown };
+};
+
+export type ClearContextCoordinatorHost<
+  Session extends ClearContextSession<Turn>,
+  Turn extends ClearContextTurn,
+> = {
+  currentSession(sessionId: string): Session | undefined;
+  closeQueryStream(session: Session): void;
+  restartSession(
+    params: NewSessionRequest,
+    options: { publicSessionId: string; permissionMode: PermissionMode },
+  ): Promise<Session>;
+  applyFastMode(session: Session, enabled: boolean): Promise<void>;
+  publishSessionState(
+    sessionId: string,
+    mode: PermissionMode,
+    configOptions: SessionConfigOption[],
+  ): Promise<void>;
+  continuationMessage(sessionId: string, plan: string, promptUuid: string): SDKUserMessage;
+  ensureConsumer(session: Session, sessionId: string): void;
+  logError(message: string, error: unknown): void;
+};
+
+function restartParams<Session extends ClearContextSession>(session: Session): NewSessionRequest {
+  const originalParams = session.creationParams ?? { cwd: session.cwd, mcpServers: [] };
+  const originalMeta = originalParams._meta as
+    ({ claudeCode?: { options?: Options } } & Record<string, unknown>) | undefined;
+  const originalOptions = originalMeta?.claudeCode?.options;
+  const unmanagedOptions = { ...(originalOptions ?? {}) };
+  delete unmanagedOptions.model;
+  delete unmanagedOptions.agent;
+  delete unmanagedOptions.effort;
+
+  return {
+    ...originalParams,
+    _meta: {
+      ...(originalMeta ?? {}),
+      claudeCode: {
+        ...(originalMeta?.claudeCode ?? {}),
+        options: {
+          ...unmanagedOptions,
+          ...(session.models.currentModelId !== DEFAULT_MODEL_ID
+            ? { model: session.models.currentModelId }
+            : {}),
+          ...(session.effortPinnedLevel !== undefined
+            ? { effort: session.effortPinnedLevel as EffortLevel }
+            : {}),
+        },
+      },
+    },
+  };
+}
+
+/** Replace Claude's private conversation and attach the still-pending ACP turn
+ * to it. The host owns provider-specific creation and stream mechanics; this
+ * coordinator owns the ordering and state transfer invariants. */
+export async function continuePlanInFreshContext<
+  Turn extends ClearContextTurn,
+  Session extends ClearContextSession<Turn>,
+>(
+  sessionId: string,
+  oldSession: Session,
+  reset: ClearContextReset,
+  host: ClearContextCoordinatorHost<Session, Turn>,
+  signal?: AbortSignal,
+): Promise<void> {
+  const assertRestartActive = (session?: Session): void => {
+    if (signal?.aborted || (session && host.currentSession(sessionId) !== session)) {
+      throw new Error("Clear-context restart aborted");
+    }
+  };
+  assertRestartActive();
+  const turn = oldSession.activeTurn;
+  if (!turn || turn.settled || host.currentSession(sessionId) !== oldSession) {
+    throw new Error("Cannot clear context without an active ACP turn");
+  }
+
+  const params = restartParams(oldSession);
+  host.closeQueryStream(oldSession);
+
+  const freshSession = await host.restartSession(params, {
+    publicSessionId: sessionId,
+    permissionMode: reset.mode,
+  });
+  assertRestartActive(freshSession);
+
+  // Do not consume the reset or mutate the turn until a replacement exists.
+  // A failed restart must remain distinguishable from a lost query transport.
+  turn.carriedUsage = { ...oldSession.accumulatedUsage };
+  turn.carriedModelUsage = { ...oldSession.accumulatedModelUsage };
+  oldSession.pendingExitPlanContextReset = undefined;
+  if (oldSession.fastModeEnabled !== freshSession.fastModeEnabled) {
+    try {
+      await host.applyFastMode(freshSession, oldSession.fastModeEnabled);
+    } catch (error) {
+      host.logError("Failed to restore Fast mode after clearing context:", error);
+    }
+    assertRestartActive(freshSession);
+  }
+
+  oldSession.activeTurn = null;
+  oldSession.turnQueue = [];
+  freshSession.turnQueue = [turn];
+  freshSession.contextUsedTokens = 0;
+
+  try {
+    await host.publishSessionState(sessionId, reset.mode, freshSession.configOptions);
+  } catch (error) {
+    host.logError("Failed to publish clear-context session state:", error);
+  }
+  assertRestartActive(freshSession);
+
+  freshSession.input.push(host.continuationMessage(sessionId, reset.plan, turn.promptUuid));
+  assertRestartActive(freshSession);
+  host.ensureConsumer(freshSession, sessionId);
+}

src/context-compaction-meta.ts

@@ -0,0 +1,30 @@
+import { AIR_CONTEXT_COMPACTION_KEY, withAirMeta } from "./air-extension.js";
+
+export const CONTEXT_COMPACTION_META_VERSION = 1;
+
+export type ContextCompactionTrigger = "manual" | "automatic";
+
+export interface ContextCompactionMetadata {
+  version: typeof CONTEXT_COMPACTION_META_VERSION;
+  trigger?: ContextCompactionTrigger;
+  preTokens?: number;
+  postTokens?: number;
+  durationMs?: number;
+  error?: string;
+}
+
+/**
+ * The `_meta` of a context compaction report:
+ * `_meta.jetbrains.air.contextCompaction`, as `docs/air-extensions.md`
+ * defines. The standard toolCallId and status fields own lifecycle identity
+ * and phase; this extension carries only compaction-specific facts. Only AIR
+ * gets it.
+ */
+export function createContextCompactionMeta(
+  metadata: Omit<ContextCompactionMetadata, "version"> = {},
+): Record<string, unknown> {
+  return withAirMeta(undefined, AIR_CONTEXT_COMPACTION_KEY, {
+    version: CONTEXT_COMPACTION_META_VERSION,
+    ...metadata,
+  } satisfies ContextCompactionMetadata);
+}

src/context-compaction.ts

@@ -0,0 +1,427 @@
+import { ClientCapabilities, SessionNotification } from "@agentclientprotocol/sdk";
+import {
+  ContextCompactionMetadata,
+  createContextCompactionMeta,
+} from "./context-compaction-meta.js";
+import { compactionToolCall } from "./tool-calls/reporters/compaction.js";
+
+type CompactionStatus = "completed" | "failed";
+type TerminalStatus = CompactionStatus | "cancelled";
+
+/**
+ * How compaction reaches the client.
+ *
+ * - `compaction_update`: the ACP session-compaction contract (ID-addressed
+ *   `compaction_update` / `compaction_summary_chunk`), used when the v1 client
+ *   advertises `clientCapabilities.session.compaction`.
+ * - `tool_call`: the legacy synthetic "Compact conversation" tool call, kept
+ *   for clients that do not advertise the capability.
+ */
+export type CompactionPresentation = "tool_call" | "compaction_update";
+
+type CompactionState = {
+  /** Doubles as the toolCallId under the legacy presentation. */
+  compactionId: string;
+  terminalStatus?: TerminalStatus;
+  heartbeatSent: boolean;
+  /** The summary text that went out as chunks. */
+  streamedSummary?: string;
+  /** User-displayable summary reported by the PostCompact hook. While the
+   *  compaction is in progress it awaits the terminal update; on a `completed`
+   *  state it has been sent. */
+  summary?: string;
+};
+
+type SendUpdate = (notification: SessionNotification) => Promise<void>;
+
+export type ContextCompactionLifecycleOptions = {
+  sessionId: string;
+  presentation?: CompactionPresentation;
+  /** Receives failures of the send that must not propagate: the turn-boundary
+   *  `cancelled` terminal. */
+  logError?: (message: string, error: unknown) => void;
+  /** The client is AIR. Only AIR gets the compaction facts, under `_meta.jetbrains.air`. */
+  airClient?: boolean;
+};
+
+export function clientSupportsCompactionUpdates(capabilities?: ClientCapabilities | null): boolean {
+  const compaction = capabilities?.session?.compaction;
+  return typeof compaction === "object" && compaction !== null && !Array.isArray(compaction);
+}
+
+/** Tags on their own line, as the model emits them; a summary that merely
+ *  quotes `<summary>` mid-sentence must not be truncated at the mention. */
+const SUMMARY_OPEN_LINE = /^[ \t]*<summary>[ \t]*\r?\n/gim;
+const SUMMARY_CLOSE_LINE = /^[ \t]*<\/summary>[ \t]*$/gim;
+/** The model's private reasoning block that precedes the summary; stripped
+ *  first so a `<summary>` it merely mentions cannot anchor the summary span,
+ *  and even when the summary tags themselves are missing. Own-line tags
+ *  anywhere; inline tags only as a leading block, since a summary body may
+ *  quote both tag names. */
+const ANALYSIS_BLOCKS = [
+  /^[ \t]*<analysis>[ \t]*\r?\n[\s\S]*?\n[ \t]*<\/analysis>[ \t]*$/gim,
+  /^\s*<analysis>[\s\S]*?<\/analysis>/i,
+];
+/** The framing Claude Code wraps around the retained summary when it persists
+ *  it as the post-compaction user message. */
+const CONTINUATION_PREAMBLE = /^\s*This session is being continued from a previous conversation/i;
+const PERSISTED_PREAMBLE =
+  /^\s*This session is being continued from a previous conversation[^\n]*\n+Summary:[ \t]*\r?\n/;
+const PERSISTED_TRAILERS = [
+  /\n+If you need specific details from before compaction[\s\S]*$/,
+  /\n+(?:Please )?[Cc]ontinue the conversation from where it left (?:it )?off[\s\S]*$/,
+];
+
+/**
+ * Reduce Claude's compaction output to the user-displayable summary.
+ *
+ * The PostCompact hook reports the model's raw output, which wraps the
+ * summary in `<summary>` tags (often preceded by an `<analysis>` block). The
+ * persisted transcript instead frames the same summary with continuation
+ * instructions for the model. Neither framing belongs in the ACP `summary`,
+ * and a continuation prompt whose framing is not recognized yields no summary
+ * at all rather than model-facing instructions.
+ */
+export function compactionSummaryText(raw: string): string | undefined {
+  let text = raw;
+  for (const block of ANALYSIS_BLOCKS) {
+    text = text.replace(block, "");
+  }
+  const tagged = taggedSummary(text);
+  if (tagged !== undefined) {
+    text = tagged;
+  } else if (CONTINUATION_PREAMBLE.test(text)) {
+    const body = text.replace(PERSISTED_PREAMBLE, "");
+    if (body === text) return undefined;
+    text = body;
+    for (const trailer of PERSISTED_TRAILERS) {
+      text = text.replace(trailer, "");
+    }
+  }
+  text = text.trim();
+  return text.length > 0 ? text : undefined;
+}
+
+function taggedSummary(raw: string): string | undefined {
+  const close = [...raw.matchAll(SUMMARY_CLOSE_LINE)].at(-1);
+  if (close?.index !== undefined) {
+    const open = [...raw.slice(0, close.index).matchAll(SUMMARY_OPEN_LINE)].at(-1);
+    if (open?.index !== undefined) {
+      return raw.slice(open.index + open[0].length, close.index);
+    }
+  }
+  // Inline tags: the widest span, so a quoted `</summary>` inside the body
+  // does not end it early. Plain index scans keep an unterminated tag linear.
+  const openInline = raw.search(/<summary>/i);
+  const closeInline = raw.toLowerCase().lastIndexOf("</summary>");
+  if (openInline >= 0 && closeInline > openInline) {
+    return raw.slice(openInline + "<summary>".length, closeInline);
+  }
+  return undefined;
+}
+
+/** True for the post-compaction user message Claude Code persists (and
+ *  `getSessionMessages` returns) with the summary of the dropped history. */
+export function isCompactSummaryMessage(message: unknown): boolean {
+  return (
+    typeof message === "object" &&
+    message !== null &&
+    (message as { type?: unknown }).type === "user" &&
+    (message as { isCompactSummary?: unknown }).isCompactSummary === true
+  );
+}
+
+/**
+ * Translates Claude's compaction signals into one idempotent ACP lifecycle.
+ *
+ * The SDK can duplicate terminal compact_result messages and can omit the
+ * opening status on replay. State therefore lives until the owning turn's
+ * result (or abort), while a new compacting status after a terminal outcome
+ * starts a fresh lifecycle.
+ */
+export class ContextCompactionLifecycle {
+  private activeCompaction: CompactionState | undefined;
+  private outputDelivered = false;
+  private duplicateErrorOutput: string | undefined;
+  /** After interruption, uncorrelated terminal frames and hooks may still
+   *  arrive from the abandoned work, including an opening we never consumed.
+   *  Wait for a known new turn before accepting them again. */
+  private interrupted = false;
+  /** Summary reported by PostCompact before the opening status was consumed.
+   *  Deliberately survives `reset()`: the CLI awaits the hook before emitting
+   *  the compaction's terminal frames, so a pending summary always belongs to
+   *  a compaction whose frames are still ahead of the consumer — possibly
+   *  queued behind a previous turn's result. */
+  private pendingSummary: string | undefined;
+  private readonly sessionId: string;
+  readonly presentation: CompactionPresentation;
+  private readonly logError: (message: string, error: unknown) => void;
+  private readonly airClient: boolean;
+
+  constructor(
+    private readonly sendUpdate: SendUpdate,
+    options: ContextCompactionLifecycleOptions,
+  ) {
+    this.sessionId = options.sessionId;
+    this.presentation = options.presentation ?? "tool_call";
+    this.logError = options.logError ?? (() => {});
+    this.airClient = options.airClient ?? false;
+  }
+
+  get hasDeliveredOutput(): boolean {
+    return this.outputDelivered;
+  }
+
+  /**
+   * Close the lifecycle at a turn boundary (result, cancel, idle-abandon).
+   *
+   * A `compaction_update` entity still `in_progress` here never received its
+   * terminal signal from the runtime and gets its one terminal status,
+   * `cancelled`. The legacy tool call is deliberately left as it was (an
+   * `in_progress` call): ACP `ToolCallStatus` has no cancelled state and that
+   * presentation's behavior predates this lifecycle. Never throws — a failed
+   * send is logged, so callers can settle the turn unconditionally.
+   */
+  async reset(): Promise<void> {
+    const state = this.activeCompaction;
+    this.activeCompaction = undefined;
+    this.outputDelivered = false;
+    this.duplicateErrorOutput = undefined;
+    if (!state || state.terminalStatus || this.presentation !== "compaction_update") return;
+    state.terminalStatus = "cancelled";
+    await this.sendQuietly(
+      {
+        sessionUpdate: "compaction_update",
+        compactionId: state.compactionId,
+        status: "cancelled",
+      },
+      "cancelled compaction",
+    );
+  }
+
+  /** Abandon the current work before settling its prompt or tearing down the
+   *  stream. Unlike a normal result boundary, its pending hooks are not safe
+   *  to carry into the next compaction. A hook has no command ID, so even an
+   *  early hook for the next compaction must be omitted until the stream gives
+   *  us a new live turn boundary. Idempotent and best-effort. */
+  async interrupt(): Promise<void> {
+    if (this.presentation === "compaction_update") {
+      this.interrupted = true;
+      this.pendingSummary = undefined;
+    }
+    await this.reset();
+  }
+
+  /** A live command's dispatch/echo proves the interrupted command's tail
+   *  has drained in the SDK's FIFO stream. Do not reset normal lifecycle
+   *  state: compaction may already have started before the user echo. */
+  resume(): void {
+    this.interrupted = false;
+  }
+
+  /**
+   * Claude also emits a failed manual compaction's error as local-command
+   * stdout. Consume that one duplicate after the lifecycle carried it,
+   * without hiding unrelated command output.
+   */
+  consumeDuplicateErrorOutput(content: string): boolean {
+    if (
+      this.duplicateErrorOutput === undefined ||
+      content.trim() !== this.duplicateErrorOutput.trim()
+    ) {
+      return false;
+    }
+    this.duplicateErrorOutput = undefined;
+    return true;
+  }
+
+  async start(compactionId: string): Promise<void> {
+    if (this.interrupted) return;
+    if (this.activeCompaction && !this.activeCompaction.terminalStatus) {
+      return;
+    }
+
+    this.open(compactionId);
+    if (this.presentation === "compaction_update") {
+      await this.send({
+        sessionUpdate: "compaction_update",
+        compactionId,
+        status: "in_progress",
+        ...(this.airClient ? { _meta: createContextCompactionMeta() } : {}),
+      });
+      return;
+    }
+    await this.send(compactionToolCall.started(compactionId, this.airClient));
+  }
+
+  /**
+   * Streaming progress from the API's compaction content block.
+   *
+   * Under `compaction_update` the block's text is the retained summary and
+   * streams as `compaction_summary_chunk`s — but only into an entity the CLI
+   * announced with its `compacting` status. The block alone carries no
+   * terminal signal, so opening an entity from it would leave nothing but the
+   * turn-boundary `cancelled` to close a compaction that succeeded. The legacy
+   * tool call keeps its historical behavior: open on first sight, re-assert
+   * `in_progress` once.
+   */
+  async heartbeat(fallbackId: string, summaryChunk?: string): Promise<void> {
+    if (this.presentation === "compaction_update") {
+      const state = this.activeCompaction;
+      if (!state || state.terminalStatus || !summaryChunk) return;
+      state.streamedSummary = (state.streamedSummary ?? "") + summaryChunk;
+      await this.send({
+        sessionUpdate: "compaction_summary_chunk",
+        compactionId: state.compactionId,
+        content: { type: "text", text: summaryChunk },
+      });
+      return;
+    }
+
+    if (!this.activeCompaction) await this.start(fallbackId);
+    const state = this.activeCompaction;
+    if (!state || state.terminalStatus || state.heartbeatSent) return;
+    state.heartbeatSent = true;
+    await this.send(compactionToolCall.inProgress(state.compactionId, this.airClient));
+  }
+
+  /**
+   * The PostCompact hook's summary. The CLI awaits the hook before emitting
+   * the compaction's terminal frames, so the summary lands while its
+   * compaction is `in_progress` and rides on the terminal update. Anything
+   * else — no entity yet, or the entity is a previous, already-terminal
+   * compaction of the same turn whose status frame the consumer is still
+   * catching up to — belongs to the compaction whose frames are ahead of the
+   * consumer, and waits for it. Only the `compaction_update` presentation
+   * carries the summary; the legacy tool call never exposed it. Never throws:
+   * it runs detached from a hook callback. Returns whether a summary was
+   * retained.
+   */
+  recordSummary(rawSummary: unknown): boolean {
+    if (this.interrupted) return false;
+    if (this.presentation !== "compaction_update" || typeof rawSummary !== "string") return false;
+    const summary = compactionSummaryText(rawSummary);
+    if (!summary) return false;
+
+    const state = this.activeCompaction;
+    if (state && !state.terminalStatus) {
+      state.summary = summary;
+    } else {
+      this.pendingSummary = summary;
+    }
+    return true;
+  }
+
+  async finish(
+    compactionId: string,
+    status: CompactionStatus,
+    metadata: Omit<ContextCompactionMetadata, "version"> = {},
+    enrichTerminal = false,
+  ): Promise<void> {
+    if (this.interrupted) return;
+    // The opening status can be missed (replay, or a terminal-only runtime):
+    // the first update for the ID is then already terminal.
+    const opened = this.activeCompaction === undefined;
+    const firstTerminal = !this.activeCompaction?.terminalStatus;
+    const state = this.activeCompaction ?? this.open(compactionId, status);
+    if (firstTerminal) {
+      state.terminalStatus = status;
+    } else if (!enrichTerminal) {
+      return;
+    }
+    if (status === "failed" && metadata.error) {
+      this.duplicateErrorOutput = metadata.error;
+    }
+    const terminalStatus = state.terminalStatus ?? status;
+    const hasMetadata = Object.keys(metadata).length > 0;
+
+    if (this.presentation === "compaction_update") {
+      // A summary that went out as chunks is not sent again in full. The
+      // chunks are the raw API text and the summary is the cleaned hook text,
+      // so the summary is left out only when both hold the same text.
+      const summaryStreamed = state.streamedSummary === state.summary;
+      const summary =
+        firstTerminal && terminalStatus === "completed" && !summaryStreamed
+          ? state.summary
+          : undefined;
+      await this.send({
+        sessionUpdate: "compaction_update",
+        compactionId: state.compactionId,
+        status: terminalStatus,
+        ...(summary !== undefined ? { summary: [{ type: "text", text: summary }] } : {}),
+        ...(terminalStatus === "failed" && metadata.error ? { error: metadata.error } : {}),
+        // `_meta` is a replace-patch: seed it with the first terminal, then
+        // only re-send it when the boundary adds facts, so a status-only
+        // duplicate can't wipe the token counts.
+        // The standard `error` field carries the error, so `_meta` does not.
+        // Only AIR gets the compaction facts.
+        ...(this.airClient && (firstTerminal || hasMetadata)
+          ? { _meta: createContextCompactionMeta(withoutError(metadata)) }
+          : {}),
+      });
+      return;
+    }
+
+    await this.send(
+      compactionToolCall.finished(
+        state.compactionId,
+        opened || firstTerminal ? status : undefined,
+        metadata,
+        opened,
+        this.airClient,
+      ),
+    );
+  }
+
+  /** Make `compactionId` the active entity, moving a pending hook summary onto
+   *  it, and mark compaction output as delivered for the owning turn. */
+  private open(compactionId: string, terminalStatus?: TerminalStatus): CompactionState {
+    const state: CompactionState = {
+      compactionId,
+      heartbeatSent: false,
+      ...(terminalStatus ? { terminalStatus } : {}),
+      ...(this.pendingSummary !== undefined ? { summary: this.pendingSummary } : {}),
+    };
+    this.pendingSummary = undefined;
+    this.activeCompaction = state;
+    this.outputDelivered = true;
+    return state;
+  }
+
+  private send(update: SessionNotification["update"]): Promise<void> {
+    return this.sendUpdate({ sessionId: this.sessionId, update });
+  }
+
+  private async sendQuietly(update: SessionNotification["update"], what: string): Promise<void> {
+    try {
+      await this.send(update);
+    } catch (error) {
+      this.logError(`Failed to send the ${what} update for session ${this.sessionId}`, error);
+    }
+  }
+}
+
+function withoutError({
+  error: _error,
+  ...facts
+}: Omit<ContextCompactionMetadata, "version">): Omit<ContextCompactionMetadata, "version"> {
+  return facts;
+}
+
+export function contextCompactionMetadataFromBoundary(compactMetadata: {
+  trigger: "manual" | "auto";
+  pre_tokens: number;
+  post_tokens?: number;
+  duration_ms?: number;
+}): Omit<ContextCompactionMetadata, "version"> {
+  return {
+    trigger: compactMetadata.trigger === "auto" ? "automatic" : "manual",
+    preTokens: compactMetadata.pre_tokens,
+    ...(compactMetadata.post_tokens !== undefined
+      ? { postTokens: compactMetadata.post_tokens }
+      : {}),
+    ...(compactMetadata.duration_ms !== undefined
+      ? { durationMs: compactMetadata.duration_ms }
+      : {}),
+  };
+}

src/diff.ts

@@ -0,0 +1,586 @@
+import { ToolCallContent, ToolCallLocation } from "@agentclientprotocol/sdk";
+import { structuredPatch } from "diff";
+import { constants } from "node:fs";
+import { type FileHandle, open } from "node:fs/promises";
+import path from "node:path";
+import { AIR_DIFF_PATCH_CAPABILITY, withAirMeta } from "./air-extension.js";
+import { normalizeWriteInput } from "./tool-calls/reporters/file-edit.js";
+
+/**
+ * The largest file, in bytes, that the adapter turns into a git patch.
+ *
+ * A larger file, a larger new text, or an Edit whose result can be larger
+ * gets no patch. The tool call then keeps its standard ACP content. The limit
+ * bounds the file read, the replacement, and the line diff that run while
+ * Claude waits for an approval.
+ */
+export const MAX_PATCH_FILE_BYTES = 1024 * 1024;
+
+/**
+ * The wall-clock budget, in milliseconds, of one line diff for a patch.
+ *
+ * The diff runs synchronously, so the budget is also the longest block of the
+ * event loop.
+ */
+const PATCH_DIFF_TIMEOUT_MS = 100;
+
+/** The number of context lines around a change in a hunk. */
+const PATCH_CONTEXT_LINES = 3;
+
+/** Git reads this many leading bytes to decide that a file is binary. */
+const BINARY_SNIFF_BYTES = 8000;
+
+const NO_NEWLINE_MARKER = "\\ No newline at end of file";
+
+/**
+ * One unified-diff hunk in the `diff` package convention.
+ *
+ * A side with zero lines stores the number of the line after the change as its
+ * start. {@link hunkHeader} converts that start to the git convention.
+ */
+interface PatchHunk {
+  oldStart: number;
+  oldLines: number;
+  newStart: number;
+  newLines: number;
+  lines: string[];
+}
+
+interface DiffToolResponse {
+  filePath?: string;
+  structuredPatch?: PatchHunk[];
+  /** FileWriteOutput only (FileEditOutput carries no `type`): whether the
+   *  write created the file or overwrote an existing one. */
+  type?: "create" | "update";
+  /** FileWriteOutput only: the content that was written. */
+  content?: string;
+  /** The pre-change content. It is null on a Write create, or on a Write
+   *  update whose previous content was too large to include. An Edit that
+   *  creates a file reports an empty string, as for an existing empty file. */
+  originalFile?: string | null;
+  /** FileEditOutput only: the text that the Edit replaced. It is empty when
+   *  the Edit created the file or filled an existing empty file. */
+  oldString?: string;
+}
+
+interface EditPreviewInput {
+  file_path?: unknown;
+  old_string?: unknown;
+  new_string?: unknown;
+  replace_all?: unknown;
+}
+
+/** The kind of file change that a git patch describes. */
+type FileChange = "create" | "update";
+
+/**
+ * Builds the exact patch shown before Claude runs an Edit or Write tool.
+ *
+ * Returns undefined when the adapter cannot predict the file change exactly.
+ * The caller then keeps the standard tool-call content. The adapter declines
+ * a file that is missing for an Edit, too large, binary, or that has CR line
+ * endings. Claude converts the line endings of an edited file, so an in-memory
+ * replacement would not match the bytes that Claude writes. It also declines
+ * an `old_string` that does not match exactly once, because Claude then
+ * normalizes quotes or fails.
+ *
+ * A Write always gets content that shows the change: the patch, the standard
+ * diff of a text that cannot have an exact patch, or a notice that the Write
+ * overwrites a file that the adapter cannot show.
+ *
+ * The preview uses the tool input as it is. Claude can still remove the
+ * trailing whitespace of a line before it writes. The PostToolUse hook then
+ * sends the patch of the written file.
+ */
+export async function previewPatchContent(
+  toolName: string,
+  input: Record<string, unknown>,
+  cwd?: string,
+): Promise<ToolCallContent[] | undefined> {
+  if (toolName === "Edit") {
+    const edit = input as EditPreviewInput;
+    if (
+      typeof edit.file_path !== "string" ||
+      typeof edit.old_string !== "string" ||
+      typeof edit.new_string !== "string"
+    ) {
+      return undefined;
+    }
+    const oldString = edit.old_string;
+    const filePath = resolveToolPath(edit.file_path, cwd);
+    const oldText = await readPatchSource(filePath);
+    if (oldText === undefined) return undefined;
+    const newString = edit.new_string;
+    if (oldString === newString || !isPatchableText(newString)) return undefined;
+    if (oldString.length === 0) {
+      // An empty old_string creates the file, or fills an existing file that
+      // holds only whitespace. `trim` also removes a byte order mark, whose
+      // handling the adapter does not predict, so such a file is declined.
+      if (oldText !== null && (oldText.trim() !== "" || oldText.includes("\uFEFF"))) {
+        return undefined;
+      }
+      return optionalContent(filePatch(filePath, oldText, newString)?.content);
+    }
+    if (oldText === null) return undefined;
+    const occurrences = oldText.split(oldString).length - 1;
+    if (occurrences === 0 || (edit.replace_all !== true && occurrences !== 1)) return undefined;
+    if (replacedTextBytesBound(oldText, oldString, newString, occurrences) > MAX_PATCH_FILE_BYTES) {
+      return undefined;
+    }
+    const newText = replacedText(oldText, oldString, newString, edit.replace_all === true);
+    return optionalContent(filePatch(filePath, oldText, newText)?.content);
+  }
+
+  if (toolName === "Write") {
+    const write = normalizeWriteInput(input);
+    if (typeof write?.file_path !== "string" || typeof write.content !== "string") {
+      return undefined;
+    }
+    // The Write tool call shows no diff, so the approval is the only place that
+    // shows what the Write changes.
+    const content = write.content;
+    const filePath = resolveToolPath(write.file_path, cwd);
+    const oldText = await readPatchSource(filePath);
+    if (oldText === undefined) {
+      return [
+        {
+          type: "content",
+          content: {
+            type: "text",
+            text: `Overwrites the existing file \`${write.file_path}\`. The adapter cannot show its current content.`,
+          },
+        },
+      ];
+    }
+    if (oldText === content) return undefined;
+    const standard: ToolCallContent[] = [
+      { type: "diff", path: write.file_path, oldText, newText: content },
+    ];
+    if (!isPatchableText(content)) return standard;
+    // A dense change can exceed the diff budget. The approval then shows the standard diff.
+    return optionalContent(filePatch(filePath, oldText, content)?.content) ?? standard;
+  }
+
+  return undefined;
+}
+
+/**
+ * An upper bound of the UTF-8 size, in bytes, of {@link replacedText}.
+ *
+ * The caller checks the bound before it builds the text. A `replace_all` of
+ * many short matches with a long `newString` can otherwise build a text of
+ * gigabytes before the timed line diff starts.
+ */
+function replacedTextBytesBound(
+  fileText: string,
+  oldString: string,
+  newString: string,
+  occurrences: number,
+): number {
+  const growth = Buffer.byteLength(newString, "utf8") - Buffer.byteLength(oldString, "utf8");
+  return Buffer.byteLength(fileText, "utf8") + occurrences * Math.max(0, growth);
+}
+
+/**
+ * The file text after Claude replaces `oldString` with `newString`.
+ *
+ * An empty `newString` deletes a line: when `oldString` does not end with a
+ * line break and the file holds `oldString` and a line break, Claude also
+ * removes that line break. With `replaceAll`, it then replaces only the
+ * occurrences that a line break follows.
+ */
+function replacedText(
+  fileText: string,
+  oldString: string,
+  newString: string,
+  replaceAll: boolean,
+): string {
+  const target =
+    newString === "" && !oldString.endsWith("\n") && fileText.includes(`${oldString}\n`)
+      ? `${oldString}\n`
+      : oldString;
+  return replaceAll
+    ? fileText.split(target).join(newString)
+    : fileText.replace(target, () => newString);
+}
+
+/**
+ * Builds the git patch for a finished Edit or Write from the file on disk.
+ *
+ * The Claude SDK `structuredPatch` is display data: Claude converts leading
+ * tabs to spaces and CRLF line endings to LF before it computes the hunks. A
+ * patch built from those hunks does not match the file. This function diffs
+ * `originalFile` against the written file instead. It returns undefined when
+ * it cannot build an exact patch, and the caller then sends the standard diff.
+ * A written file that contains a CR or a byte order mark is declined, because
+ * Claude removed those bytes from `originalFile`.
+ */
+export async function patchUpdateFromDiffToolResponse(
+  toolResponse: unknown,
+): Promise<{ content: ToolCallContent[]; locations: ToolCallLocation[] } | undefined> {
+  if (!toolResponse || typeof toolResponse !== "object") return undefined;
+  const response = toolResponse as DiffToolResponse;
+  if (typeof response.filePath !== "string") return undefined;
+  // An Edit with an empty old_string reports "" as the original of a created
+  // file and of an existing empty file. The response does not tell the two
+  // apart, so the caller keeps the standard diff.
+  if (response.type === undefined && response.oldString === "" && response.originalFile === "") {
+    return undefined;
+  }
+  // A Write whose content is the previous text changed nothing. The file on
+  // disk can hold a later change, and that change is not the change of this Write.
+  if (
+    response.type === "update" &&
+    typeof response.content === "string" &&
+    response.originalFile === response.content
+  ) {
+    return undefined;
+  }
+  const oldText =
+    response.type === "create"
+      ? null
+      : typeof response.originalFile === "string"
+        ? response.originalFile
+        : undefined;
+  if (oldText === undefined) return undefined;
+  // The same size limit as the new side: a larger text gets the standard diff.
+  if (oldText !== null && Buffer.byteLength(oldText, "utf8") > MAX_PATCH_FILE_BYTES)
+    return undefined;
+  const newText = await readPatchSource(response.filePath);
+  if (typeof newText !== "string" || newText.startsWith("\uFEFF")) return undefined;
+  if (response.type === "create" && newText !== response.content) return undefined;
+  const patch = filePatch(response.filePath, oldText, newText);
+  if (!patch) return undefined;
+  return {
+    content: [patch.content],
+    // A created file keeps the location of its Write tool call.
+    locations:
+      oldText === null
+        ? [{ path: response.filePath }]
+        : patch.hunks.map(({ newStart }) => ({ path: response.filePath!, line: newStart })),
+  };
+}
+
+/**
+ * Builds standard ACP diff content from the structured toolResponse provided
+ * by the PostToolUse hook for diff-producing tools (Edit, Write). Unlike
+ * parsing the plain unified diff string, this uses the pre-parsed
+ * structuredPatch which supports multiple replacement sites (replaceAll) and
+ * always includes context lines for better readability.
+ */
+export function toolUpdateFromDiffToolResponse(toolResponse: unknown): {
+  content?: ToolCallContent[];
+  locations?: ToolCallLocation[];
+} {
+  if (!toolResponse || typeof toolResponse !== "object") return {};
+  const response = toolResponse as DiffToolResponse;
+  if (!response.filePath || !Array.isArray(response.structuredPatch)) return {};
+
+  const content: ToolCallContent[] = [];
+  const locations: ToolCallLocation[] = [];
+  for (const { lines, newStart } of response.structuredPatch) {
+    const oldText: string[] = [];
+    const newText: string[] = [];
+    for (const line of lines) {
+      if (line.startsWith("-")) {
+        oldText.push(line.slice(1));
+      } else if (line.startsWith("+")) {
+        newText.push(line.slice(1));
+      } else if (line === NO_NEWLINE_MARKER) {
+        continue;
+      } else {
+        oldText.push(line.slice(1));
+        newText.push(line.slice(1));
+      }
+    }
+    if (oldText.length > 0 || newText.length > 0) {
+      locations.push({ path: response.filePath, line: newStart });
+      content.push({
+        type: "diff",
+        path: response.filePath,
+        oldText: oldText.join("\n") || null,
+        newText: newText.join("\n"),
+      });
+    }
+  }
+
+  // A Write `update` can arrive with an empty structuredPatch — nothing
+  // changed, the diff timed out, or the previous content was too large to
+  // diff (originalFile null; SDK 0.3.252 documents the lane). Returning `{}`
+  // would leave Write's optimistic tool_use-time content standing, and that
+  // was built with `oldText: null` — "creation" semantics — so an overwrite
+  // of a large existing file would render as creating it. Emit a truthful
+  // replacement instead. Gated on `type` so Edit (whose output carries no
+  // `type` and whose optimistic old/new diff is already truthful) keeps the
+  // empty-return behavior. A `create` needs nothing here: the
+  // tool_use-time diff shows the created file, and a client with diffPatch
+  // gets it from the Write reporter.
+  if (content.length === 0 && response.type === "update" && typeof response.content === "string") {
+    locations.push({ path: response.filePath });
+    content.push(
+      typeof response.originalFile === "string"
+        ? {
+            type: "diff",
+            path: response.filePath,
+            oldText: response.originalFile,
+            newText: response.content,
+          }
+        : {
+            type: "content",
+            content: {
+              type: "text",
+              text: `Updated \`${response.filePath}\` (previous content too large to diff)`,
+            },
+          },
+    );
+  }
+
+  const result: { content?: ToolCallContent[]; locations?: ToolCallLocation[] } = {};
+  if (content.length > 0) result.content = content;
+  if (locations.length > 0) result.locations = locations;
+  return result;
+}
+
+/**
+ * The text of one git patch for `filePath`.
+ *
+ * The headers follow `git diff`: the path loses its leading slash, gets the
+ * `a/` and `b/` prefixes, and is quoted when git would quote it. A created
+ * file gets its mode line and a `/dev/null` side.
+ */
+export function gitPatchText(filePath: string, change: FileChange, hunks: PatchHunk[]): string {
+  return [
+    ...gitPatchHeader(filePath, change),
+    ...hunks.flatMap((hunk) => [hunkHeader(hunk), ...hunk.lines]),
+    "",
+  ].join("\n");
+}
+
+function gitPatchHeader(filePath: string, change: FileChange): string[] {
+  // git drops one leading slash of an absolute path; a Windows path gets
+  // forward slashes so the header names the same file on every platform.
+  const name = filePath.replaceAll("\\", "/").replace(/^\/+/u, "");
+  const oldName = quoteGitPath("a/", name);
+  const newName = quoteGitPath("b/", name);
+  // git ends a ---/+++ name that contains a space with a tab, for GNU patch.
+  const tab = name.includes(" ") ? "\t" : "";
+  return [
+    `diff --git ${oldName} ${newName}`,
+    ...(change === "create" ? ["new file mode 100644"] : []),
+    `--- ${change === "create" ? "/dev/null" : `${oldName}${tab}`}`,
+    `+++ ${newName}${tab}`,
+  ];
+}
+
+const GIT_PATH_ESCAPES: Record<number, string> = {
+  0x07: "a",
+  0x08: "b",
+  0x09: "t",
+  0x0a: "n",
+  0x0b: "v",
+  0x0c: "f",
+  0x0d: "r",
+  0x22: '"',
+  0x5c: "\\",
+};
+
+/**
+ * Quotes `prefix + name` like git with the default `core.quotePath`.
+ *
+ * A double quote, a backslash, a control byte, or a non-ASCII byte makes git
+ * put the whole name in double quotes. git then writes a C escape or a
+ * three-digit octal escape for each such UTF-8 byte.
+ */
+function quoteGitPath(prefix: string, name: string): string {
+  const full = `${prefix}${name}`;
+  let quoted = "";
+  let needsQuotes = false;
+  for (const byte of Buffer.from(full, "utf8")) {
+    const escape = GIT_PATH_ESCAPES[byte];
+    if (escape !== undefined) {
+      quoted += `\\${escape}`;
+      needsQuotes = true;
+    } else if (byte < 0x20 || byte >= 0x7f) {
+      quoted += `\\${byte.toString(8).padStart(3, "0")}`;
+      needsQuotes = true;
+    } else {
+      quoted += String.fromCharCode(byte);
+    }
+  }
+  return needsQuotes ? `"${quoted}"` : full;
+}
+
+function hunkHeader({ oldStart, oldLines, newStart, newLines }: PatchHunk): string {
+  return `@@ -${hunkRange(oldStart, oldLines)} +${hunkRange(newStart, newLines)} @@`;
+}
+
+/** A git hunk range. A side with zero lines names the line before the change. */
+function hunkRange(start: number, count: number): string {
+  if (count === 0) return `${Math.max(0, start - 1)},0`;
+  return count === 1 ? String(start) : `${start},${count}`;
+}
+
+/** The hunk that adds every line of `text` to an empty file. */
+function wholeFileHunk(text: string): PatchHunk | undefined {
+  if (text.length === 0) return undefined;
+  const terminated = text.endsWith("\n");
+  const lines = (terminated ? text.slice(0, -1) : text).split("\n");
+  return {
+    oldStart: 1,
+    oldLines: 0,
+    newStart: 1,
+    newLines: lines.length,
+    lines: [...lines.map((line) => `+${line}`), ...(terminated ? [] : [NO_NEWLINE_MARKER])],
+  };
+}
+
+/**
+ * The line-diff hunks between two texts. Returns undefined when the diff runs
+ * out of its time budget.
+ */
+function diffHunks(oldText: string | null, newText: string): PatchHunk[] | undefined {
+  if (oldText === null) {
+    const hunk = wholeFileHunk(newText);
+    return hunk ? [hunk] : [];
+  }
+  const oldLines = textLines(oldText);
+  const newLines = textLines(newText);
+  // The diff gets only the changed middle and its context lines. An edit
+  // usually changes a small part of a large file.
+  const common = Math.min(oldLines.length, newLines.length);
+  let prefix = 0;
+  while (prefix < common && oldLines[prefix] === newLines[prefix]) prefix++;
+  let suffix = 0;
+  while (
+    suffix < common - prefix &&
+    oldLines[oldLines.length - 1 - suffix] === newLines[newLines.length - 1 - suffix]
+  ) {
+    suffix++;
+  }
+  const skipped = Math.max(0, prefix - PATCH_CONTEXT_LINES);
+  const skippedEnd = Math.max(0, suffix - PATCH_CONTEXT_LINES);
+  const patch = structuredPatch(
+    "",
+    "",
+    oldLines.slice(skipped, oldLines.length - skippedEnd).join(""),
+    newLines.slice(skipped, newLines.length - skippedEnd).join(""),
+    "",
+    "",
+    { context: PATCH_CONTEXT_LINES, timeout: PATCH_DIFF_TIMEOUT_MS },
+  );
+  return patch?.hunks.map((hunk) => ({
+    ...hunk,
+    oldStart: hunk.oldStart + skipped,
+    newStart: hunk.newStart + skipped,
+  }));
+}
+
+/** The lines of a text, each with its line break. The last line can have none. */
+function textLines(text: string): string[] {
+  return text.match(/[^\n]*\n|[^\n]+$/g) ?? [];
+}
+
+/**
+ * The git patch of a file change and its hunks. Returns undefined when
+ * nothing changed or the diff runs out of its time budget.
+ */
+function filePatch(
+  filePath: string,
+  oldText: string | null,
+  newText: string,
+): { content: ToolCallContent; hunks: PatchHunk[] } | undefined {
+  const hunks = diffHunks(oldText, newText);
+  if (!hunks || hunks.length === 0) return undefined;
+  const change = oldText === null ? "create" : "update";
+  return { content: patchContent(filePath, gitPatchText(filePath, change, hunks)), hunks };
+}
+
+/**
+ * Reads a file as patch input.
+ *
+ * Returns null when the file does not exist. Returns undefined when the file
+ * cannot be read, is not a regular file, is larger than
+ * {@link MAX_PATCH_FILE_BYTES}, is binary, is not valid UTF-8, or contains a
+ * CR.
+ */
+async function readPatchSource(filePath: string): Promise<string | null | undefined> {
+  let handle: FileHandle;
+  try {
+    // O_NONBLOCK keeps the open of a FIFO from waiting for a writer. It does not change a regular file.
+    handle = await open(filePath, constants.O_RDONLY | constants.O_NONBLOCK);
+  } catch (error) {
+    return isMissingFileError(error) ? null : undefined;
+  }
+  try {
+    // The checks and the read use one open file, so a swap of the path between them has no effect.
+    const stats = await handle.stat();
+    if (!stats.isFile() || stats.size > MAX_PATCH_FILE_BYTES) return undefined;
+    // One byte more than the checked size shows a file that grew after the check.
+    const buffer = Buffer.alloc(stats.size + 1);
+    let length = 0;
+    while (length < buffer.length) {
+      const { bytesRead } = await handle.read(buffer, length, buffer.length - length, length);
+      if (bytesRead === 0) break;
+      length += bytesRead;
+    }
+    if (length > stats.size) return undefined;
+    const text = decodeFileText(buffer.subarray(0, length));
+    return text?.includes("\r") ? undefined : text;
+  } catch {
+    return undefined;
+  } finally {
+    await handle.close();
+  }
+}
+
+/** The text of a file of at most {@link MAX_PATCH_FILE_BYTES} that is not binary and is valid UTF-8. */
+function decodeFileText(bytes: Uint8Array): string | undefined {
+  if (bytes.length > MAX_PATCH_FILE_BYTES) return undefined;
+  if (bytes.subarray(0, BINARY_SNIFF_BYTES).includes(0)) return undefined;
+  try {
+    return new TextDecoder("utf-8", { fatal: true, ignoreBOM: true }).decode(bytes);
+  } catch {
+    return undefined;
+  }
+}
+
+/** Whether a tool input text can be the new side of an exact patch. */
+function isPatchableText(text: string): boolean {
+  return (
+    Buffer.byteLength(text, "utf8") <= MAX_PATCH_FILE_BYTES &&
+    !text.includes("\0") &&
+    !text.includes("\r")
+  );
+}
+
+function optionalContent(content: ToolCallContent | undefined): ToolCallContent[] | undefined {
+  return content ? [content] : undefined;
+}
+
+/**
+ * A diff block in the AIR patch form.
+ *
+ * `oldText: null` and `newText: ""` only satisfy the ACP schema. The adapter
+ * sends this form only to a client that advertised `diffPatch`.
+ */
+function patchContent(filePath: string, text: string): ToolCallContent {
+  return {
+    type: "diff",
+    path: filePath,
+    oldText: null,
+    newText: "",
+    _meta: withAirMeta(undefined, AIR_DIFF_PATCH_CAPABILITY, {
+      version: 1,
+      format: "git_patch",
+      text,
+    }),
+  };
+}
+
+function resolveToolPath(filePath: string, cwd?: string): string {
+  return path.isAbsolute(filePath) ? filePath : path.resolve(cwd ?? process.cwd(), filePath);
+}
+
+function isMissingFileError(error: unknown): boolean {
+  return error instanceof Error && "code" in error && error.code === "ENOENT";
+}

src/elicitation.ts

@@ -12,6 +12,7 @@ import type {
   AskUserQuestionInput,
   AskUserQuestionOutput,
 } from "@anthropic-ai/claude-agent-sdk/sdk-tools.js";
+import { AIR_CUSTOM_ANSWER_KEY, withAirMeta } from "./air-extension.js";
 
 /**
  * Bridges between the Claude Agent SDK's elicitation/dialog callbacks and ACP's
@@ -148,14 +149,6 @@ function questionCustomFieldKey(index: number): string {
  */
 const OPTION_META_KEY = "_claude/askUserQuestionOption";
 
-/**
- * Shared `_meta` key for marking a per-question free-text field as the custom
- * answer companion for a select question. This intentionally has no
- * agent-specific namespace so ACP clients can recognize the same marker across
- * Codex, Claude, and other AskUserQuestion bridges.
- */
-const CUSTOM_ANSWER_META_KEY = "_askUserQuestionCustomAnswer";
-
 /**
  * Render the AskUserQuestion tool's questions as an ACP form elicitation.
  *
@@ -168,14 +161,17 @@ const CUSTOM_ANSWER_META_KEY = "_askUserQuestionCustomAnswer";
  *
  * Each question is followed by its own optional free-text "custom answer" field
  * (`question_<n>_custom`), mirroring the CLI's per-question "Other" box: the
- * user can type their own answer instead of picking an option, scoped to that
- * specific question. Nothing is marked required, so the user can also just skip
- * — matching the built-in tool, which always offers Skip + a free-text box.
+ * user can type their own answer instead of picking an option, add it to a
+ * multi-select's picks, or attach it as a note to a single-select's pick (see
+ * `applyAskElicitationResponse`), scoped to that specific question. Nothing is
+ * marked required, so the user can also just skip — matching the built-in tool,
+ * which always offers Skip + a free-text box.
  */
 export function askUserQuestionsToCreateRequest(
   questions: AskUserQuestion[],
   sessionId: string,
   toolCallId: string | undefined,
+  airClient = false,
 ): CreateElicitationRequest {
   const single = questions.length === 1;
   const properties: Record<string, ElicitationPropertySchema> = {};
@@ -211,13 +207,19 @@ export function askUserQuestionsToCreateRequest(
     properties[questionCustomFieldKey(index)] = {
       type: "string",
       title: "Other",
-      description: "Type your own answer instead of choosing an option above (optional).",
-      _meta: {
-        [CUSTOM_ANSWER_META_KEY]: {
-          questionId: questionFieldKey(index),
-          isCustomAnswer: true,
-        },
-      },
+      description: question.multiSelect
+        ? "Type your own answer to add to your selection above (optional)."
+        : "Type your own answer, or add a note to the option you chose above (optional).",
+      // Marks the field as the custom answer companion of a select question,
+      // under `_meta.jetbrains.air.customAnswer`. Only AIR gets the marker.
+      ...(airClient
+        ? {
+            _meta: withAirMeta(undefined, AIR_CUSTOM_ANSWER_KEY, {
+              questionId: questionFieldKey(index),
+              isCustomAnswer: true,
+            }),
+          }
+        : {}),
     };
   });
 
@@ -241,17 +243,36 @@ export function askUserQuestionsToCreateRequest(
 export type AskUserQuestionOutcome =
   { action: "answered"; updatedInput: Record<string, unknown> } | { action: "cancel" };
 
+/**
+ * Serialize a multi-select answer the way the CLI's own AskUserQuestion UI
+ * does: comma-joined, with any item that itself contains the separator (or a
+ * double quote) JSON-quoted. The tool's `call()` splits the string back on the
+ * same rule, so a free-text answer like `Redis, not Memcached` stays one item
+ * instead of reading as two more picks.
+ */
+function joinMultiSelectAnswer(items: string[]): string {
+  return items
+    .map((item) => (item.includes(", ") || item.includes('"') ? JSON.stringify(item) : item))
+    .join(", ");
+}
+
 /**
  * Fold an ACP elicitation response into the AskUserQuestion tool's input.
  *
  * Selected labels are read back from the indexed form fields and written into
- * `answers` as a `{ [questionText]: label }` map (comma-joining multi-selects)
- * — the key shape the tool's own `call()` reads. A non-empty per-question
- * custom-answer field (`question_<n>_custom`) takes precedence over that
- * question's selection, since the user typed their own answer instead of
- * picking one. Decline yields empty answers (the model is told the user skipped
- * rather than the turn aborting); cancel — and any custom/future action we
- * don't understand — aborts the tool call.
+ * `answers` as a `{ [questionText]: label }` map — the key shape the tool's own
+ * `call()` reads — with multi-selects comma-joined in the CLI's own quoted form
+ * (see `joinMultiSelectAnswer`). A non-empty per-question custom-answer field
+ * (`question_<n>_custom`) joins the selection of a multi-select question, where
+ * the two fields are independent and filling both means both. For a
+ * single-select question it is the answer when nothing was picked (the user
+ * typed their own instead), and otherwise travels beside the pick as the
+ * tool's own per-question `annotations[question].notes` — the slot the CLI
+ * uses for free text attached to a selection and renders to the model as
+ * `"Q"="A" notes: ...` — so a client that presents the box as a notes field
+ * cannot make the selection disappear. Decline yields empty answers (the model
+ * is told the user skipped rather than the turn aborting); cancel — and any
+ * custom/future action we don't understand — aborts the tool call.
  */
 export function applyAskElicitationResponse(
   response: CreateElicitationResponse,
@@ -270,27 +291,57 @@ export function applyAskElicitationResponse(
   // Typed against the tool's own output schema so the answer/response shapes
   // stay in sync with what the built-in tool's call() expects to read back.
   const answers: AskUserQuestionOutput["answers"] = {};
+  const annotations: NonNullable<AskUserQuestionInput["annotations"]> = {};
   questions.forEach((question, index) => {
-    // A typed custom answer wins over the selection: the user chose to write
-    // their own answer for this question instead of picking an option.
     const custom = content[questionCustomFieldKey(index)];
-    if (typeof custom === "string" && custom.trim() !== "") {
-      answers[question.question] = custom.trim();
-      return;
-    }
+    const customText = typeof custom === "string" ? custom.trim() : "";
 
     const value = content[questionFieldKey(index)];
-    if (value === undefined || value === null) {
+    const picks: string[] =
+      value === undefined || value === null
+        ? []
+        : Array.isArray(value)
+          ? value.filter((item) => item !== undefined && item !== null && item !== "").map(String)
+          : [String(value)];
+
+    // A multi-select is additive, and the form offers the selection and the
+    // custom box as independent fields — a user who fills both means both, so
+    // the typed answer joins the checked options.
+    if (question.multiSelect) {
+      const text = joinMultiSelectAnswer(customText === "" ? picks : [...picks, customText]);
+      if (text !== "") {
+        answers[question.question] = text;
+      }
       return;
     }
-    const text = Array.isArray(value) ? value.join(", ") : String(value);
-    if (text === "") {
+
+    // A single-select question is answered by exactly one thing. With no option
+    // picked, the typed text is that answer (the CLI's "Other"). With an option
+    // picked as well, the pick stays the answer and the text rides along as the
+    // tool's per-question `notes` annotation, so neither is lost. A single-select
+    // normally holds one item; the plain join only matters if a client hands
+    // back an array for it, and then mirrors the old behavior.
+    const picked = picks.join(", ");
+    if (picked === "") {
+      if (customText !== "") {
+        answers[question.question] = customText;
+      }
       return;
     }
-    answers[question.question] = text;
+    answers[question.question] = picked;
+    if (customText !== "") {
+      annotations[question.question] = { notes: customText };
+    }
   });
 
-  return { action: "answered", updatedInput: { ...toolInput, answers } };
+  return {
+    action: "answered",
+    updatedInput: {
+      ...toolInput,
+      answers,
+      ...(Object.keys(annotations).length > 0 ? { annotations } : {}),
+    },
+  };
 }
 
 /**

src/exit-plan.ts

@@ -0,0 +1,232 @@
+import type { SessionNotification } from "@agentclientprotocol/sdk";
+import type { SDKResultMessage } from "@anthropic-ai/claude-agent-sdk";
+import {
+  type ClearContextCoordinatorHost,
+  type ClearContextReset,
+  type ClearContextSession,
+  type ClearContextTurn,
+  continuePlanInFreshContext,
+} from "./clear-context-coordinator.js";
+import { parseToolResultMeta } from "./tool-result-meta.js";
+
+export function acceptedPlanToolResult(
+  notification: SessionNotification,
+  toolUseId: string | undefined,
+): SessionNotification {
+  const update = notification.update;
+  if (
+    !toolUseId ||
+    update.sessionUpdate !== "tool_call_update" ||
+    update.toolCallId !== toolUseId
+  ) {
+    return notification;
+  }
+  const completed = { ...update };
+  delete completed.rawOutput;
+  delete completed.content;
+  return { ...notification, update: { ...completed, status: "completed" } };
+}
+
+function containsToolResultFor(content: unknown, toolUseId: string): boolean {
+  return (
+    Array.isArray(content) &&
+    content.some(
+      (block) =>
+        typeof block === "object" &&
+        block !== null &&
+        (block as { type?: unknown }).type === "tool_result" &&
+        (block as { tool_use_id?: unknown }).tool_use_id === toolUseId,
+    )
+  );
+}
+
+type ExitPlanState = {
+  toolUseCache: Record<string, { name: string } | undefined>;
+  pendingExitPlanModeInterruption?: { toolUseId: string; toolResultSeen: boolean };
+  pendingExitPlanContextReset?: ClearContextReset;
+};
+
+function rejectedExitPlanToolUseId(
+  content: unknown,
+  toolUseCache: ExitPlanState["toolUseCache"],
+  rawToolResultMeta: unknown,
+): string | undefined {
+  if (!Array.isArray(content)) return undefined;
+  const toolResultMeta = parseToolResultMeta(rawToolResultMeta);
+  if (!toolResultMeta) return undefined;
+  for (const block of content) {
+    if (typeof block !== "object" || block === null) continue;
+    const { type, tool_use_id: toolUseId, is_error: isError } = block as Record<string, unknown>;
+    if (
+      type === "tool_result" &&
+      typeof toolUseId === "string" &&
+      isError === true &&
+      toolResultMeta.get(toolUseId)?.nonExecutionKind === "user-rejected" &&
+      toolUseCache[toolUseId]?.name === "ExitPlanMode"
+    ) {
+      return toolUseId;
+    }
+  }
+  return undefined;
+}
+
+/** Reconcile an SDK user message with the two pending ExitPlanMode lanes and
+ * return the accepted plan tool id whose rendered update must be completed. */
+export function observeExitPlanToolResults(
+  message: { type: string; tool_result_meta?: unknown },
+  content: unknown,
+  state: ExitPlanState,
+): string | undefined {
+  if (message.type !== "user") return undefined;
+
+  const rejectedToolUseId = rejectedExitPlanToolUseId(
+    content,
+    state.toolUseCache,
+    message.tool_result_meta,
+  );
+  if (rejectedToolUseId) {
+    // The stream is authoritative: resumed queries can lose the short-lived
+    // marker installed by canUseTool, while metadata preserves correlation.
+    state.pendingExitPlanModeInterruption = {
+      toolUseId: rejectedToolUseId,
+      toolResultSeen: true,
+    };
+  }
+
+  const pendingInterruption = state.pendingExitPlanModeInterruption;
+  if (pendingInterruption && containsToolResultFor(content, pendingInterruption.toolUseId)) {
+    pendingInterruption.toolResultSeen = true;
+  }
+
+  const pendingReset = state.pendingExitPlanContextReset;
+  return pendingReset && containsToolResultFor(content, pendingReset.toolUseId)
+    ? pendingReset.toolUseId
+    : undefined;
+}
+
+export function executionDiagnostic(message: SDKResultMessage): string | undefined {
+  if (message.subtype === "success") {
+    return message.result.startsWith("[ede_diagnostic]") ? message.result : undefined;
+  }
+  return message.errors.find((error) => error.startsWith("[ede_diagnostic]"));
+}
+
+/** Whether `message` is the error-shaped diagnostic Claude emits for the cycle
+ * a recorded ExitPlanMode `interrupt: true` answer stopped. */
+export function isExitPlanInterruptionResult(
+  message: SDKResultMessage,
+  pending: ExitPlanState["pendingExitPlanModeInterruption"],
+): boolean {
+  if (!pending?.toolResultSeen || !message.is_error) return false;
+  const diagnostic = executionDiagnostic(message);
+  return (
+    !!diagnostic &&
+    /(?:^|\s)result_type=user(?:\s|$)/.test(diagnostic) &&
+    /(?:^|\s)stop_reason=tool_use(?:\s|$)/.test(diagnostic)
+  );
+}
+
+/** Claude wraps a rejected ExitPlanMode explanation in a Markdown code fence.
+ * Strip exactly one complete outer fence for that tool only. */
+export function exitPlanModeRawOutput(toolName: string, content: unknown): unknown {
+  if (toolName !== "ExitPlanMode" || typeof content !== "string") {
+    return content;
+  }
+  const fenced = /^\s*```[^\r\n]*\r?\n([\s\S]*?)\r?\n```\s*$/.exec(content);
+  return fenced?.[1] ?? content;
+}
+
+export type ExitPlanRestartHost<
+  Session extends ClearContextSession<Turn>,
+  Turn extends ClearContextTurn,
+> = Omit<
+  ClearContextCoordinatorHost<Session, Turn>,
+  "publishSessionState" | "continuationMessage"
+> & {
+  sessionUpdate(notification: SessionNotification): Promise<void>;
+  destroyReplacement(sessionId: string, session: Session): void;
+  settleCancelledTurn(oldSession: Session, turnSession: Session, turn: Turn): void;
+  settleFailedTurn(turnSession: Session, turn: Turn, error: unknown): void;
+};
+
+/** Owns the lifetime of accepted-plan context replacements. In particular, a
+ * session cancellation invalidates an in-progress async restart so a late
+ * restartSession result cannot recreate a closed public session. */
+export class ExitPlanCoordinator<
+  Session extends ClearContextSession<Turn>,
+  Turn extends ClearContextTurn,
+> {
+  private readonly restarts = new Map<string, AbortController>();
+
+  constructor(private readonly host: ExitPlanRestartHost<Session, Turn>) {}
+
+  cancel(sessionId: string): void {
+    this.restarts.get(sessionId)?.abort();
+  }
+
+  async restart(sessionId: string, oldSession: Session, reset: ClearContextReset): Promise<void> {
+    this.cancel(sessionId);
+    const controller = new AbortController();
+    this.restarts.set(sessionId, controller);
+    try {
+      const clearContextHost: ClearContextCoordinatorHost<Session, Turn> = {
+        ...this.host,
+        publishSessionState: async (id, mode, configOptions) => {
+          await this.host.sessionUpdate({
+            sessionId: id,
+            update: { sessionUpdate: "current_mode_update", currentModeId: mode },
+          });
+          await this.host.sessionUpdate({
+            sessionId: id,
+            update: { sessionUpdate: "config_option_update", configOptions },
+          });
+        },
+        continuationMessage: (id, plan, promptUuid) => ({
+          type: "user",
+          message: {
+            role: "user",
+            content: [{ type: "text", text: `Implement the following plan:\n\n${plan}` }],
+          },
+          session_id: id,
+          parent_tool_use_id: null,
+          origin: { kind: "human" },
+          uuid: promptUuid as `${string}-${string}-${string}-${string}-${string}`,
+        }),
+      };
+      await continuePlanInFreshContext(
+        sessionId,
+        oldSession,
+        reset,
+        clearContextHost,
+        controller.signal,
+      );
+    } catch (error) {
+      const currentSession = this.host.currentSession(sessionId);
+      const replacement = currentSession !== oldSession ? currentSession : undefined;
+      if (replacement) this.host.destroyReplacement(sessionId, replacement);
+
+      const turn = replacement?.activeTurn ?? oldSession.activeTurn;
+      if (turn && !turn.settled) {
+        const turnSession = replacement?.activeTurn === turn ? replacement : oldSession;
+        if (controller.signal.aborted) {
+          this.host.settleCancelledTurn(oldSession, turnSession, turn);
+        } else {
+          // A provider/session-creation failure is turn-scoped. Settling it
+          // here keeps it out of the query consumer's transport-loss catch.
+          this.host.settleFailedTurn(turnSession, turn, error);
+        }
+        oldSession.activeTurn = null;
+        oldSession.turnQueue = (oldSession.turnQueue ?? []).filter((queued) => queued !== turn);
+        if (replacement) {
+          replacement.activeTurn = null;
+          replacement.turnQueue = (replacement.turnQueue ?? []).filter((queued) => queued !== turn);
+        }
+      }
+      oldSession.pendingExitPlanContextReset = undefined;
+    } finally {
+      if (this.restarts.get(sessionId) === controller) {
+        this.restarts.delete(sessionId);
+      }
+    }
+  }
+}

src/file-change-audit.ts

@@ -0,0 +1,335 @@
+import type { Query, RewindFilesResult } from "@anthropic-ai/claude-agent-sdk";
+import * as fs from "node:fs";
+import * as path from "node:path";
+import { airExtensionMeta, clientSupportsAirCapability, withAirMeta } from "./air-extension.js";
+
+export const AGENT_FILE_CHANGE_REPORT_CAPABILITY = "agentFileChangeReport";
+
+const MAX_REPORTED_PATHS = 1024;
+const MAX_REPORTED_PATH_LENGTH = 4096;
+export const AGENT_FILE_CHANGE_REPORT_MAX_BYTES = 256 * 1024;
+export const AGENT_FILE_CHANGE_REPORT_TIMEOUT_MS = 2_000;
+const REQUEST_ID_PATTERN = /^[A-Za-z0-9._:-]{1,128}$/;
+
+export type FileChangeReportTurnState = {
+  requestId: string;
+  phase: "requested" | "collecting" | "finished";
+};
+
+export type NativeFileChangeReportTurn = {
+  promptUuid: string;
+  fileChangeReport?: FileChangeReportTurnState;
+};
+
+export type FileChangeReportWorkspace = {
+  cwd: string;
+  additionalDirectories: string[];
+};
+
+export type AgentFileChangeReportResult = {
+  version: 1;
+  requestId: string;
+} & (
+  | {
+      status: "reported";
+      paths: string[];
+      declaredComplete: boolean;
+      truncated: boolean;
+    }
+  | {
+      status: "unavailable";
+      reason: FileChangeReportUnavailableReason;
+    }
+);
+
+export type FileChangeReportUnavailableReason =
+  "cancelled" | "timeout" | "invalidOutput" | "notReported" | "providerError";
+
+type NativeFileChangeReporterOptions = {
+  cwd: string;
+  additionalDirectories: string[];
+  publish: (result: AgentFileChangeReportResult) => Promise<void>;
+  logError: (message: string) => void;
+  timeoutMs?: number;
+};
+
+export type NativeFileChangeReporter = {
+  request(meta: unknown): FileChangeReportTurnState | undefined;
+  report(
+    turn: NativeFileChangeReportTurn | null | undefined,
+    query: Pick<Query, "rewindFiles">,
+  ): Promise<void>;
+  finish(
+    state: FileChangeReportTurnState | undefined,
+    reason: FileChangeReportUnavailableReason,
+  ): void;
+};
+
+export function agentFileChangeReportRequestId(meta: unknown): string | undefined {
+  const air = airExtensionMeta(meta);
+  const request = air?.agentFileChangeReportRequest;
+  if (!request || typeof request !== "object" || Array.isArray(request)) return undefined;
+  const requestRecord = request as Record<string, unknown>;
+  const requestKeys = Object.keys(requestRecord);
+  if (
+    requestKeys.length !== 2 ||
+    !requestKeys.includes("version") ||
+    !requestKeys.includes("requestId") ||
+    requestRecord.version !== 1
+  )
+    return undefined;
+  const requestId = requestRecord.requestId;
+  return typeof requestId === "string" && REQUEST_ID_PATTERN.test(requestId)
+    ? requestId
+    : undefined;
+}
+
+export function supportsAgentFileChangeReport(capabilities: unknown): boolean {
+  return clientSupportsAirCapability(capabilities, AGENT_FILE_CHANGE_REPORT_CAPABILITY);
+}
+
+export function agentFileChangeReportMeta(
+  result: AgentFileChangeReportResult,
+): Record<string, unknown> {
+  return withAirMeta(undefined, AGENT_FILE_CHANGE_REPORT_CAPABILITY, result);
+}
+
+export function createNativeFileChangeReporter(
+  options: NativeFileChangeReporterOptions,
+): NativeFileChangeReporter {
+  const workspace = normalizeWorkspace(options.cwd, options.additionalDirectories);
+  const timeoutMs = options.timeoutMs ?? AGENT_FILE_CHANGE_REPORT_TIMEOUT_MS;
+  const requestIds = new Set<string>();
+
+  const publish = async (state: FileChangeReportTurnState, result: AgentFileChangeReportResult) => {
+    if (state.phase === "finished") return;
+    state.phase = "finished";
+    try {
+      await options.publish(result);
+    } catch (error) {
+      options.logError(`Failed to publish file-change report ${state.requestId}: ${error}`);
+    }
+  };
+
+  const finishUnavailable = async (
+    state: FileChangeReportTurnState,
+    reason: FileChangeReportUnavailableReason,
+  ) => {
+    await publish(state, {
+      version: 1,
+      requestId: state.requestId,
+      status: "unavailable",
+      reason,
+    });
+  };
+
+  const report = async (
+    turn: NativeFileChangeReportTurn | null | undefined,
+    query: Pick<Query, "rewindFiles">,
+  ) => {
+    const state = turn?.fileChangeReport;
+    if (!state || state.phase !== "requested") return;
+    state.phase = "collecting";
+
+    let timer: ReturnType<typeof setTimeout> | undefined;
+    const previewPromise = query.rewindFiles(turn.promptUuid, { dryRun: true });
+    // A timed-out control request may still settle later. Observe it so a late
+    // rejection cannot become unhandled, but never let it publish a second terminal.
+    void previewPromise.catch(() => {});
+    try {
+      const preview = await Promise.race<RewindFilesResult | null>([
+        previewPromise,
+        new Promise<null>((resolve) => {
+          timer = setTimeout(() => resolve(null), timeoutMs);
+          timer.unref?.();
+        }),
+      ]);
+      if (preview === null) {
+        await finishUnavailable(state, "timeout");
+        return;
+      }
+      if (!preview.canRewind || !Array.isArray(preview.filesChanged)) {
+        await finishUnavailable(state, "invalidOutput");
+        return;
+      }
+
+      const normalized = normalizeReportedPaths(preview.filesChanged, workspace);
+      await publish(
+        state,
+        fitReportedAgentFileChangeReport({
+          version: 1,
+          requestId: state.requestId,
+          status: "reported",
+          paths: normalized.paths,
+          // Checkpoints cover Claude file tools, but not every mutation source
+          // (notably Bash and most subagents), so this list is never exhaustive.
+          declaredComplete: false,
+          truncated: normalized.truncated,
+        }),
+      );
+    } catch (error) {
+      options.logError(`Failed to inspect Claude file checkpoint ${turn.promptUuid}: ${error}`);
+      await finishUnavailable(state, "providerError");
+    } finally {
+      if (timer) clearTimeout(timer);
+    }
+  };
+
+  return {
+    request(meta) {
+      const requestId = agentFileChangeReportRequestId(meta);
+      if (!requestId || requestIds.has(requestId)) return undefined;
+      requestIds.add(requestId);
+      return { requestId, phase: "requested" };
+    },
+    report,
+    finish(state, reason) {
+      if (!state) return;
+      void finishUnavailable(state, reason);
+    },
+  };
+}
+
+function normalizeWorkspace(
+  cwd: string,
+  additionalDirectories: string[],
+): FileChangeReportWorkspace {
+  const normalizedCwd = canonicalizeWorkspaceRoot(path.resolve(cwd));
+  const seen = new Set([pathKey(normalizedCwd)]);
+  const normalizedAdditionalDirectories: string[] = [];
+  for (const directory of additionalDirectories) {
+    const normalized = canonicalizeWorkspaceRoot(path.resolve(normalizedCwd, directory));
+    const key = pathKey(normalized);
+    if (seen.has(key)) continue;
+    seen.add(key);
+    normalizedAdditionalDirectories.push(normalized);
+  }
+  return {
+    cwd: normalizedCwd,
+    additionalDirectories: normalizedAdditionalDirectories,
+  };
+}
+
+function normalizeReportedPaths(
+  reportedPaths: string[],
+  workspace: FileChangeReportWorkspace,
+): { paths: string[]; truncated: boolean } {
+  const roots = [workspace.cwd, ...workspace.additionalDirectories];
+  const seen = new Set<string>();
+  const result: string[] = [];
+  let totalBytes = 0;
+  let truncated = false;
+  for (const reportedPath of reportedPaths) {
+    if (
+      typeof reportedPath !== "string" ||
+      reportedPath.trim().length === 0 ||
+      reportedPath.length > MAX_REPORTED_PATH_LENGTH ||
+      hasControlCharacter(reportedPath)
+    ) {
+      truncated = true;
+      continue;
+    }
+    let normalized: string;
+    try {
+      normalized = canonicalizeReportedPath(path.resolve(workspace.cwd, reportedPath));
+    } catch {
+      truncated = true;
+      continue;
+    }
+    if (normalized.length > MAX_REPORTED_PATH_LENGTH || hasControlCharacter(normalized)) {
+      truncated = true;
+      continue;
+    }
+    if (!roots.some((root) => isWithinRoot(normalized, root))) {
+      truncated = true;
+      continue;
+    }
+    const key = pathKey(normalized);
+    if (roots.some((root) => pathKey(root) === key)) {
+      truncated = true;
+      continue;
+    }
+    if (seen.has(key)) continue;
+    const pathBytes = Buffer.byteLength(normalized, "utf8");
+    if (
+      result.length >= MAX_REPORTED_PATHS ||
+      totalBytes + pathBytes > AGENT_FILE_CHANGE_REPORT_MAX_BYTES
+    ) {
+      truncated = true;
+      continue;
+    }
+    seen.add(key);
+    result.push(normalized);
+    totalBytes += pathBytes;
+  }
+  return { paths: result, truncated };
+}
+
+function fitReportedAgentFileChangeReport(
+  report: Extract<AgentFileChangeReportResult, { status: "reported" }>,
+): Extract<AgentFileChangeReportResult, { status: "reported" }> {
+  const paths = [...report.paths];
+  let fitted = report;
+  while (Buffer.byteLength(JSON.stringify(fitted), "utf8") > AGENT_FILE_CHANGE_REPORT_MAX_BYTES) {
+    if (paths.length === 0) {
+      throw new Error("Agent file-change report exceeds the wire limit without paths");
+    }
+    paths.pop();
+    fitted = {
+      ...report,
+      paths: [...paths],
+      declaredComplete: false,
+      truncated: true,
+    };
+  }
+  return fitted;
+}
+
+function isWithinRoot(candidate: string, root: string): boolean {
+  const relative = path.relative(root, candidate);
+  return !path.isAbsolute(relative) && !relative.startsWith(`..${path.sep}`) && relative !== "..";
+}
+
+function canonicalizeWorkspaceRoot(value: string): string {
+  return canonicalizeFromExistingAncestor(value);
+}
+
+function canonicalizeReportedPath(value: string): string {
+  const parent = canonicalizeFromExistingAncestor(path.dirname(value));
+  return path.resolve(parent, path.basename(value));
+}
+
+function canonicalizeFromExistingAncestor(value: string): string {
+  const original = path.resolve(value);
+  let current = original;
+  const missingSegments: string[] = [];
+  while (true) {
+    try {
+      const canonical = fs.realpathSync.native(current);
+      return path.resolve(canonical, ...missingSegments.reverse());
+    } catch (error) {
+      if (!isMissingPathError(error)) return original;
+    }
+    const parent = path.dirname(current);
+    if (parent === current) return original;
+    missingSegments.push(path.basename(current));
+    current = parent;
+  }
+}
+
+function isMissingPathError(error: unknown): boolean {
+  if (typeof error !== "object" || error === null || !("code" in error)) return false;
+  return error.code === "ENOENT" || error.code === "ENOTDIR";
+}
+
+function pathKey(value: string): string {
+  return process.platform === "win32" ? value.toLowerCase() : value;
+}
+
+function hasControlCharacter(value: string): boolean {
+  for (let index = 0; index < value.length; index++) {
+    const code = value.charCodeAt(index);
+    if (code <= 0x1f || (code >= 0x7f && code <= 0x9f)) return true;
+  }
+  return false;
+}

src/fork-session.ts

@@ -0,0 +1,235 @@
+import { ForkSessionRequest, ForkSessionResponse, RequestError } from "@agentclientprotocol/sdk";
+import {
+  forkSession as forkClaudeSession,
+  getSessionMessages,
+  importSessionToStore,
+  type SessionStore,
+  type SessionStoreEntry,
+} from "@anthropic-ai/claude-agent-sdk";
+import { createHash } from "node:crypto";
+import { assistantMessageText } from "./session-failure-extension.js";
+import { SessionTiming } from "./session-timing.js";
+
+type ForkSessionMeta = {
+  [key: string]: unknown;
+  jetbrains?: {
+    air?: {
+      fork?: {
+        version?: number;
+        messageId?: string;
+        messageFingerprint?: string;
+        messageOccurrence?: number;
+      };
+    };
+  };
+};
+
+type ForkSessionDependencies = {
+  liveMessageIdToUuid?: ReadonlyMap<string, string>;
+  logger?: { log: (...args: unknown[]) => void };
+  messageIdForGrouping: (message: {
+    type?: string;
+    uuid?: string | null;
+    message?: unknown;
+  }) => string | undefined;
+};
+
+type ForkPoint = {
+  messageId: string;
+  messageFingerprint?: string;
+  messageOccurrence?: number;
+};
+
+function forkPoint(meta: unknown): ForkPoint | undefined {
+  const fork = (meta as ForkSessionMeta | null | undefined)?.jetbrains?.air?.fork;
+  if (fork?.version !== 1) return undefined;
+  const messageId = fork.messageId?.trim();
+  if (!messageId) return undefined;
+  const messageFingerprint = fork.messageFingerprint?.trim();
+  const messageOccurrence = fork.messageOccurrence;
+  return {
+    messageId,
+    ...(messageFingerprint ? { messageFingerprint } : {}),
+    // AIR computes this with count(...) over the visible prefix, so it is 1-based.
+    ...(typeof messageOccurrence === "number" &&
+    Number.isSafeInteger(messageOccurrence) &&
+    messageOccurrence > 0
+      ? { messageOccurrence }
+      : {}),
+  };
+}
+
+function forkPointMessageIdCandidates(messageId: string): string[] {
+  // Older AIR builds sent their visible segment id. Prefer the exact id before its ACP source id.
+  const protocolMessageId = messageId.replace(/:segment:\d+$/, "");
+  return protocolMessageId === messageId ? [messageId] : [messageId, protocolMessageId];
+}
+
+async function loadFullSessionHistory(
+  sessionId: string,
+  cwd: string,
+): Promise<SessionStoreEntry[]> {
+  // getSessionMessages returns only the active parentUuid chain. The import keeps inactive branches that AIR can still reference.
+  const entries: SessionStoreEntry[] = [];
+  const store: SessionStore = {
+    append: async (_key, batch) => {
+      entries.push(...batch);
+    },
+    load: async () => null,
+  };
+  await importSessionToStore(sessionId, store, { dir: cwd, includeSubagents: false });
+  return entries;
+}
+
+function assistantGroups(
+  entries: SessionStoreEntry[],
+  messageIdForGrouping: ForkSessionDependencies["messageIdForGrouping"],
+) {
+  const groups = new Map<string, { uuid?: string; text: string }>();
+  for (const entry of entries) {
+    if (
+      entry.type !== "assistant" ||
+      entry.isSidechain === true ||
+      entry.parent_tool_use_id != null ||
+      entry.parent_agent_id != null
+    ) {
+      continue;
+    }
+    const messageId = messageIdForGrouping(entry);
+    if (!messageId) continue;
+    const group = groups.get(messageId) ?? { text: "" };
+    if (typeof entry.uuid === "string" && entry.uuid.length > 0) group.uuid = entry.uuid;
+    group.text += assistantMessageText(entry.message) ?? "";
+    groups.set(messageId, group);
+  }
+  return groups;
+}
+
+function fingerprint(text: string): string {
+  return `sha256:${createHash("sha256").update(text).digest("hex")}`;
+}
+
+function fingerprintOccurrenceOnBranch(
+  targetUuid: string,
+  expectedFingerprint: string,
+  entries: SessionStoreEntry[],
+  groups: ReturnType<typeof assistantGroups>,
+  messageIdForGrouping: ForkSessionDependencies["messageIdForGrouping"],
+): number {
+  const entriesByUuid = new Map(
+    entries.flatMap((entry) => (typeof entry.uuid === "string" ? [[entry.uuid, entry]] : [])),
+  );
+  const seenGroups = new Set<string>();
+  let occurrence = 0;
+  let cursor: string | undefined = targetUuid;
+  while (cursor) {
+    const entry = entriesByUuid.get(cursor);
+    if (!entry) break;
+    if (
+      entry.type === "assistant" &&
+      entry.isSidechain !== true &&
+      entry.parent_tool_use_id == null &&
+      entry.parent_agent_id == null
+    ) {
+      const messageId = messageIdForGrouping(entry);
+      if (messageId && !seenGroups.has(messageId)) {
+        seenGroups.add(messageId);
+        const group = groups.get(messageId);
+        if (group && fingerprint(group.text) === expectedFingerprint) occurrence++;
+      }
+    }
+    cursor = typeof entry.parentUuid === "string" ? entry.parentUuid : undefined;
+  }
+  return occurrence;
+}
+
+function resolveFromFullHistory(
+  entries: SessionStoreEntry[],
+  candidates: string[],
+  point: ForkPoint,
+  messageIdForGrouping: ForkSessionDependencies["messageIdForGrouping"],
+): string | undefined {
+  const groups = assistantGroups(entries, messageIdForGrouping);
+  const exact = candidates.map((candidate) => groups.get(candidate)?.uuid).find(Boolean);
+  if (exact) return exact;
+  if (!point.messageFingerprint || !point.messageOccurrence) return undefined;
+
+  const fingerprintMatches = [...groups.values()].filter(
+    (group) => group.uuid && fingerprint(group.text) === point.messageFingerprint,
+  );
+  // If only one persisted message has this content, the fingerprint already
+  // identifies it even when an older client supplied an incompatible index.
+  if (fingerprintMatches.length === 1) return fingerprintMatches[0]?.uuid;
+
+  const occurrenceMatches = fingerprintMatches.filter(
+    (group) =>
+      group.uuid &&
+      fingerprintOccurrenceOnBranch(
+        group.uuid,
+        point.messageFingerprint!,
+        entries,
+        groups,
+        messageIdForGrouping,
+      ) === point.messageOccurrence,
+  );
+  return occurrenceMatches.length === 1 ? occurrenceMatches[0]?.uuid : undefined;
+}
+
+export async function forkSession(
+  params: ForkSessionRequest,
+  dependencies: ForkSessionDependencies,
+): Promise<ForkSessionResponse> {
+  const timing = new SessionTiming(dependencies.logger, "fork", params.sessionId);
+  const point = forkPoint(params._meta);
+  if (!point) {
+    const forked = await forkClaudeSession(params.sessionId, { dir: params.cwd });
+    timing.phase("sdk-fork", " resolution=latest");
+    return { sessionId: forked.sessionId };
+  }
+
+  const candidateIds = forkPointMessageIdCandidates(point.messageId);
+  const liveUuid = candidateIds
+    .map((candidateId) => dependencies.liveMessageIdToUuid?.get(candidateId))
+    .find(Boolean);
+  const history = liveUuid
+    ? undefined
+    : await getSessionMessages(params.sessionId, { dir: params.cwd });
+  timing.phase("active-history", ` resolution=${liveUuid ? "live" : "pending"}`);
+  const messageUuid =
+    liveUuid ??
+    candidateIds
+      .map(
+        (candidateId) =>
+          history
+            ?.slice()
+            .reverse()
+            .find((message) => dependencies.messageIdForGrouping(message) === candidateId)?.uuid,
+      )
+      .find(Boolean);
+  const fullHistoryUuid = messageUuid
+    ? undefined
+    : resolveFromFullHistory(
+        await loadFullSessionHistory(params.sessionId, params.cwd),
+        candidateIds,
+        point,
+        dependencies.messageIdForGrouping,
+      );
+  timing.phase(
+    "full-history",
+    ` resolution=${liveUuid ? "live" : messageUuid ? "active" : fullHistoryUuid ? "full" : "missing"}`,
+  );
+
+  if (!messageUuid && !fullHistoryUuid) {
+    throw RequestError.invalidParams(
+      { messageId: point.messageId },
+      `Fork point message ${point.messageId} was not found in session ${params.sessionId}`,
+    );
+  }
+
+  const forked = await forkClaudeSession(params.sessionId, {
+    dir: params.cwd,
+    upToMessageId: messageUuid ?? fullHistoryUuid,
+  });
+  timing.phase("sdk-fork");
+  return { sessionId: forked.sessionId };
+}

src/goal-extension.ts

@@ -0,0 +1,83 @@
+import { RequestError } from "@agentclientprotocol/sdk";
+import type { SDKActiveGoalMessage } from "@anthropic-ai/claude-agent-sdk";
+
+export const GOAL_EXTENSION_VERSION = 1 as const;
+export const GOAL_CONTROL_METHOD = "_session/goal";
+
+export const GOAL_ACTIONS = ["set", "clear"] as const;
+export type GoalAction = (typeof GOAL_ACTIONS)[number];
+
+export type GoalCapability = {
+  version: typeof GOAL_EXTENSION_VERSION;
+  controlMethod: typeof GOAL_CONTROL_METHOD;
+  actions: GoalAction[];
+};
+
+export type GoalStatus = "active" | "paused" | "blocked" | "limited" | "complete";
+
+export type GoalSnapshot = {
+  objective: string;
+  status: GoalStatus;
+  iterations?: number;
+  lastReason?: string | null;
+  createdAt?: number;
+  updatedAt?: number;
+  tokenBudget?: number | null;
+  tokensUsed?: number;
+  timeUsedSeconds?: number;
+  controlMethod: typeof GOAL_CONTROL_METHOD;
+};
+
+export type GoalRequest =
+  { sessionId: string; action: "clear" } | { sessionId: string; action: "set"; objective: string };
+
+export type GoalControlResponse = Record<string, never>;
+
+export function goalUpdateFromPrompt(prompt: string): GoalSnapshot | null | undefined {
+  const match = /^\/goal(?:\s+([\s\S]*))?$/.exec(prompt);
+  const argument = match?.[1]?.trim();
+  if (!argument) {
+    return undefined;
+  }
+  if (argument === "clear") {
+    return null;
+  }
+  return {
+    objective: argument,
+    status: "active",
+    controlMethod: GOAL_CONTROL_METHOD,
+  };
+}
+
+export function parseGoalRequest(params: unknown): GoalRequest {
+  if (!params || typeof params !== "object") {
+    throw RequestError.invalidParams(undefined, "goal params must be an object");
+  }
+  const { sessionId, action, objective } = params as Record<string, unknown>;
+  if (typeof sessionId !== "string" || sessionId.length === 0) {
+    throw RequestError.invalidParams(undefined, "goal params require a non-empty sessionId");
+  }
+  if (!GOAL_ACTIONS.includes(action as GoalAction)) {
+    throw RequestError.invalidParams(undefined, 'goal action must be "set" or "clear"');
+  }
+  if (action === "set" && (typeof objective !== "string" || objective.trim().length === 0)) {
+    throw RequestError.invalidParams(undefined, 'goal action "set" requires a non-empty objective');
+  }
+  return action === "set"
+    ? { sessionId, action, objective: (objective as string).trim() }
+    : { sessionId, action: "clear" };
+}
+
+export function toGoalSnapshot(message: SDKActiveGoalMessage): GoalSnapshot | null {
+  if (message.value === null) {
+    return null;
+  }
+  return {
+    objective: message.value.condition.trim(),
+    status: "active",
+    iterations: message.value.iterations,
+    lastReason: message.value.last_reason ?? null,
+    createdAt: message.value.set_at,
+    controlMethod: GOAL_CONTROL_METHOD,
+  };
+}

src/hide-claude-auth.ts

@@ -0,0 +1,286 @@
+/**
+ * `--hide-claude-auth`: this integration must never bill a claude.ai
+ * subscription. The flag hides the claude.ai login method from `initialize`
+ * and makes the agent behave like a logged-out CLI whenever a subscription
+ * would pay for a turn. `acp-agent.ts` decides *when* the guard applies (flag
+ * on, no provider override) and calls in here for the *what*.
+ *
+ * The account the CLI reports at `initialize` is the source of truth. The SDK
+ * memoizes it, so it is a constant for the life of a query, and two layers
+ * keep it honest:
+ *
+ * 1. Session creation refuses an account that holds no credential this
+ *    integration accepts. A logged-out session never exists, so the client's
+ *    sign-in always leads to a new session with a fresh `initialize`. The
+ *    per-turn guard repeats the check on the same cached account, which costs
+ *    microseconds and covers a session created under a provider override that
+ *    `providers/disable` later removed.
+ * 2. A sign-out during the session ends the query. The next turn recreates it,
+ *    so the next `initialize` reports the real account and layer 1 judges it.
+ *    The recreation resumes the stored conversation. When the CLI never wrote
+ *    one, because the first turn was the one that signed out, the recreation
+ *    starts a fresh query under the same session id instead.
+ *
+ * A file-based credential replaced by a subscription between two turns is seen
+ * by the CLI probe the agent fires at the START of every user prompt. That read
+ * is never awaited, so it usually lands mid-turn; all it does there is mark the
+ * session. The guard consumes the mark at the turn boundary — the next prompt
+ * recreates the query and layer 1 judges the account the new `initialize`
+ * reports — so a probe never interrupts a running turn. A swap that happens
+ * after the last probe stays unseen until the next prompt reads the store
+ * again. Closing that window would cost a blocking read per turn.
+ */
+
+import { RequestError } from "@agentclientprotocol/sdk";
+import type { AccountInfo, Query } from "@anthropic-ai/claude-agent-sdk";
+
+export function shouldHideClaudeAuth(): boolean {
+  return process.argv.includes("--hide-claude-auth");
+}
+
+/**
+ * `data.reason` carried by the `authRequired` JSON-RPC error when the flag
+ * blocks a turn. From the client's point of view the agent is logged out (same
+ * error code and flow as a signed-out CLI); the reason lets it render a
+ * different hint. A string enum so further reasons can be added without a
+ * shape change.
+ */
+export const CLAUDE_SUBSCRIPTION_NOT_SUPPORTED_REASON = "claude_subscription_not_supported";
+export type AuthRequiredReason = typeof CLAUDE_SUBSCRIPTION_NOT_SUPPORTED_REASON;
+
+export const CLAUDE_SUBSCRIPTION_NOT_SUPPORTED_MESSAGE =
+  "This integration does not support using claude.ai subscriptions.";
+
+/** The message of the plain sign-out refusal. It carries no `reason`: the
+ *  account holds nothing this integration can bill, which is the ordinary
+ *  signed-out state every ACP client already knows how to answer. */
+export const CLAUDE_LOGIN_REQUIRED_MESSAGE =
+  "Sign in with an API key or a Console account to use this integration.";
+
+/**
+ * The `apiKeySource` values that outrank a stored subscription.
+ *
+ * The SDK documents its `ApiKeySource` type as the origin of the credential
+ * used for API requests. `ANTHROPIC_API_KEY` is the environment variable,
+ * `apiKeyHelper` is the configured helper command, and `/login managed key` is
+ * a key that `/login` created with an Anthropic Console account. Each of the
+ * three is an API key that pays instead of the subscription. Every other
+ * member means no API key is in use: `none`, and the legacy `user`, `project`,
+ * `org`, `temporary` and `oauth` that current CLIs never emit.
+ */
+const API_KEY_SOURCES_ABOVE_SUBSCRIPTION: ReadonlySet<string> = new Set([
+  "ANTHROPIC_API_KEY",
+  "apiKeyHelper",
+  "/login managed key",
+]);
+
+/**
+ * True when a turn on this account is paid by a claude.ai subscription.
+ *
+ * The SDK types `apiKeySource` and `tokenSource` as an open `string`, so this
+ * is an allowlist. An account bills the subscription only when every field
+ * proves it, and an unknown value keeps the guard on.
+ *
+ * - `subscriptionType` must be set. Without it the CLI reports no subscription.
+ * - `tokenSource` must be absent. The CLI sets it in place of the subscription
+ *   when a bearer or OAuth environment token pays for the turn.
+ * - `apiProvider` must be absent or `firstParty`. The SDK documents that the
+ *   Anthropic OAuth login applies only to `firstParty`; for a third-party
+ *   backend such as `bedrock`, `vertex`, `foundry` or `gateway` the other
+ *   fields are absent and the authentication is external.
+ * - `apiKeySource` must not be one of {@link API_KEY_SOURCES_ABOVE_SUBSCRIPTION}.
+ *   Claude Code's credential precedence puts those keys above the `/login`
+ *   subscription, so the key pays and the stored subscription is inert.
+ */
+export function billsClaudeSubscription(account: AccountInfo | undefined): boolean {
+  if (!account?.subscriptionType) {
+    return false;
+  }
+  if (account.tokenSource) {
+    return false;
+  }
+  if (account.apiProvider !== undefined && account.apiProvider !== "firstParty") {
+    return false;
+  }
+  return !API_KEY_SOURCES_ABOVE_SUBSCRIPTION.has(account.apiKeySource ?? "");
+}
+
+/**
+ * True when the account already holds a credential this integration accepts:
+ * a third-party backend, a bearer or OAuth environment token, or one of the
+ * API key sources in {@link API_KEY_SOURCES_ABOVE_SUBSCRIPTION}.
+ *
+ * False therefore covers both the signed-out CLI and the account whose only
+ * credential is a claude.ai subscription. {@link billsClaudeSubscription} runs
+ * first and separates the two, so a caller that reaches a `false` here is
+ * looking at a session with no way to pay.
+ */
+export function holdsNonSubscriptionCredential(account: AccountInfo | undefined): boolean {
+  if (!account) {
+    return false;
+  }
+  if (account.apiProvider !== undefined && account.apiProvider !== "firstParty") {
+    return true;
+  }
+  if (account.tokenSource) {
+    return true;
+  }
+  return API_KEY_SOURCES_ABOVE_SUBSCRIPTION.has(account.apiKeySource ?? "");
+}
+
+export function claudeSubscriptionNotSupportedError(): RequestError {
+  return RequestError.authRequired(
+    { reason: CLAUDE_SUBSCRIPTION_NOT_SUPPORTED_REASON satisfies AuthRequiredReason },
+    CLAUDE_SUBSCRIPTION_NOT_SUPPORTED_MESSAGE,
+  );
+}
+
+/** The signed-out refusal. Deliberately without `data`, so a client that reads
+ *  `data.reason` sees the plain ACP sign-out it already handles. */
+export function claudeLoginRequiredError(): RequestError {
+  return RequestError.authRequired(undefined, CLAUDE_LOGIN_REQUIRED_MESSAGE);
+}
+
+/**
+ * The state the guard keeps for one session. It lives on the session so that a
+ * concurrent pair of turns shares one account read, and so
+ * that each degraded-guard warning is logged once.
+ */
+export type ClaudeSubscriptionGuardState = {
+  /** The in-flight guard run. Set before the first `await`. */
+  pendingRun?: Promise<RequestError | undefined>;
+  /** True after the "no account source" warning was logged for this session. */
+  degradedWarningLogged?: boolean;
+};
+
+export type GuardLogger = {
+  error: (...args: unknown[]) => void;
+  warn?: (...args: unknown[]) => void;
+};
+
+function warn(logger: GuardLogger, message: string): void {
+  (logger.warn ?? logger.error).call(logger, message);
+}
+
+/**
+ * Report once per session that the guard cannot read the account at all. The
+ * guard is then absent, not passing. The CLI build decides this, not the user,
+ * so a message on every turn would only add noise.
+ */
+export function warnClaudeSubscriptionGuardDegraded(options: {
+  sessionId: string;
+  guardState: ClaudeSubscriptionGuardState;
+  logger: GuardLogger;
+  cause: string;
+}): void {
+  const { guardState } = options;
+  if (guardState.degradedWarningLogged) {
+    return;
+  }
+  guardState.degradedWarningLogged = true;
+  warn(
+    options.logger,
+    `Session ${options.sessionId}: the --hide-claude-auth subscription guard is degraded ` +
+      `(${options.cause}). This session cannot detect a claude.ai subscription.`,
+  );
+}
+
+type GuardOptions = {
+  sessionId: string;
+  query: Pick<Query, "accountInfo">;
+  guardState: ClaudeSubscriptionGuardState;
+  logger: GuardLogger;
+  /** Display hook: called with the account the guard just read, before the
+   *  guard decides on it. It exists so a refused turn still reports which
+   *  account it was refused for. Purely observational — this module knows
+   *  nothing about what the caller does with it, and a throw from here never
+   *  changes the verdict. */
+  onAccount?: (account: AccountInfo) => void;
+};
+
+/**
+ * The per-turn guard for a live session.
+ *
+ * It decides on the account the SDK cached at `initialize`, which is this
+ * integration's source of truth. That account is a constant for the life of
+ * the query, so the check costs microseconds. It still earns its place: it
+ * covers a session created under a provider override that `providers/disable`
+ * later removed, so the create-time check never ran for the routing in force
+ * now. A sign-out ends the query (see `markSessionForSignOutRespawn` in
+ * `acp-agent.ts`), so the next turn recreates it and `initialize` reports the
+ * real account. This guard does not see the residual case the module header
+ * names either.
+ *
+ * A turn is refused when the account bills a subscription, and also when it
+ * holds nothing this integration accepts, which is the user signing out in
+ * mid-session. The refusal mirrors the signed-out path exactly (see
+ * `failActiveWithSessionFailure` for `auth_required` in `acp-agent.ts`): every
+ * client gets the `authRequired` JSON-RPC rejection that starts its own auth
+ * flow. The guard sends no separate access message.
+ *
+ * Fails open when no account can be read at all: session creation already
+ * refused every account without a usable credential, and an unavailable probe
+ * must not block a session that passed that check.
+ */
+export async function refuseClaudeSubscriptionTurn(options: GuardOptions): Promise<void> {
+  // Concurrent turns must not each re-read the account and each publish a row.
+  // Store the run before the first await, and let the others await the same one.
+  const { guardState } = options;
+  const run = (guardState.pendingRun ??= evaluateGuard(options).finally(() => {
+    if (guardState.pendingRun === run) {
+      guardState.pendingRun = undefined;
+    }
+  }));
+  const refusal = await run;
+  if (refusal) {
+    throw refusal;
+  }
+}
+
+/** Read the account and return the error for the refused turn.
+ *  Never throws: an unreadable account fails open. */
+async function evaluateGuard(options: GuardOptions): Promise<RequestError | undefined> {
+  const account = await readGuardAccount(options);
+  if (!account) {
+    return undefined;
+  }
+  // Before the decision, so the client learns the identity even when the next
+  // lines refuse the turn. A display hook must never fail a guard.
+  try {
+    options.onAccount?.(account);
+  } catch (error) {
+    options.logger.error(
+      `Session ${options.sessionId}: the guard's onAccount hook threw:`,
+      error instanceof Error ? error.message : String(error),
+    );
+  }
+  if (billsClaudeSubscription(account)) {
+    return claudeSubscriptionNotSupportedError();
+  }
+  if (!holdsNonSubscriptionCredential(account)) {
+    return claudeLoginRequiredError();
+  }
+  return undefined;
+}
+
+/** The account the SDK cached at `initialize`. `undefined` when the query
+ *  cannot answer at all. */
+async function readGuardAccount(options: GuardOptions): Promise<AccountInfo | undefined> {
+  const { query } = options;
+  if (typeof query.accountInfo !== "function") {
+    warnClaudeSubscriptionGuardDegraded({
+      ...options,
+      cause: "the SDK query has no accountInfo method",
+    });
+    return undefined;
+  }
+  try {
+    return await query.accountInfo();
+  } catch (error) {
+    options.logger.error(
+      `Session ${options.sessionId}: accountInfo failed; skipping the subscription check for this turn:`,
+      error instanceof Error ? error.message : String(error),
+    );
+    return undefined;
+  }
+}

src/index.ts

@@ -1,8 +1,10 @@
 #!/usr/bin/env node
 
-import { resolveSettings } from "@anthropic-ai/claude-agent-sdk";
 import { claudeCliPath, runAcp } from "./acp-agent.js";
+import { applyManagedPolicyEnv } from "./managed-policy.js";
 import packageJson from "../package.json" with { type: "json" };
+import { appendFileSync, mkdirSync } from "node:fs";
+import { join } from "node:path";
 
 // `--cli` is checked first so that `--version`/`-v` (and any other flags) are
 // forwarded to the wrapped native CLI rather than swallowed by our own version
@@ -42,13 +44,10 @@ if (process.argv.includes("--cli")) {
   process.exit(0);
 } else {
   // Apply env vars from the managed-policy tier before any SDK call so the
-  // SDK subprocess inherits them. Going through resolveSettings (vs. a raw
-  // read of managed-settings.json) also picks up MDM sources on macOS and
-  // HKLM/HKCU on Windows.
-  const policy = await resolveSettings({ settingSources: [] });
-  for (const [key, value] of Object.entries(policy.effective.env ?? {})) {
-    process.env[key] = value;
-  }
+  // SDK subprocess inherits them. Reading the tier is best-effort: a transient
+  // failure leaves the agent running with no policy env instead of aborting
+  // module evaluation here, before any ACP traffic.
+  await applyManagedPolicyEnv();
 
   // stdout is used to send messages to the client
   // we redirect everything else to stderr to make sure it doesn't interfere with ACP
@@ -61,7 +60,29 @@ if (process.argv.includes("--cli")) {
     console.error("Unhandled Rejection at:", promise, "reason:", reason);
   });
 
-  const { connection, agent } = runAcp();
+  const logDirectory = process.env.CLAUDE_AGENT_LOGS;
+  const logger = logDirectory
+    ? (() => {
+        mkdirSync(logDirectory, { recursive: true });
+        const logFile = join(logDirectory, "agent.log");
+        const writeLog = (...args: unknown[]) => {
+          const rendered = args
+            .map((arg) => (arg instanceof Error ? (arg.stack ?? arg.message) : String(arg)))
+            .join(" ");
+          appendFileSync(logFile, `${new Date().toISOString()} pid=${process.pid} ${rendered}\n`);
+        };
+        return {
+          log: writeLog,
+          error: (...args: unknown[]) => {
+            console.error(...args);
+            writeLog(...args);
+          },
+        };
+      })()
+    : undefined;
+  logger?.log("Claude ACP started");
+
+  const { connection, agent } = runAcp(logger);
 
   async function shutdown() {
     await agent.dispose().catch((err) => {

src/lib.ts

@@ -18,6 +18,15 @@ export {
   toolUpdateFromToolResult,
 } from "./tools.js";
 export { SettingsManager, type SettingsManagerOptions } from "./settings.js";
+// The `authStatus` extension's wire surface: the notification's method name and
+// the payload types needed to read the traffic. The mappers stay internal.
+export {
+  AUTH_STATUS_UPDATE_METHOD,
+  type AuthStatus,
+  type AuthStatusAccount,
+  type AuthStatusKind,
+  type AuthStatusUpdateNotification,
+} from "./auth-status.js";
 
 // Export types
 export type { ClaudePlanEntry } from "./tools.js";

src/managed-policy.ts

@@ -0,0 +1,34 @@
+import { resolveSettings } from "@anthropic-ai/claude-agent-sdk";
+
+/**
+ * Applies the managed-policy tier's env vars to `process.env` before any SDK
+ * call, so the SDK subprocess inherits them. Going through `resolveSettings`
+ * rather than a raw read of `managed-settings.json` also picks up MDM sources on
+ * macOS and `HKLM`/`HKCU` on Windows.
+ *
+ * Reading the tier is best-effort by nature: on a host with no MDM and no
+ * managed policy the result is empty and the agent behaves identically. So a
+ * transient failure to read it — `EINTR`, `EMFILE`, `EAGAIN` — must leave the
+ * agent running with no policy env rather than stop it from starting.
+ *
+ * That guard matters because the caller awaits this at module scope in an ESM
+ * entry point, where a rejection aborts module evaluation and the process exits
+ * before serving any ACP traffic. `SettingsManager.loadAllSettings` wraps the
+ * same SDK call for the same reason.
+ */
+export async function applyManagedPolicyEnv(
+  resolve: typeof resolveSettings = resolveSettings,
+  env: Record<string, string | undefined> = process.env,
+): Promise<void> {
+  let policy: Awaited<ReturnType<typeof resolveSettings>>;
+  try {
+    policy = await resolve({ settingSources: [] });
+  } catch (error) {
+    // stderr, so the ACP stream on stdout stays clean.
+    console.error("Failed to resolve managed policy settings:", error);
+    return;
+  }
+  for (const [key, value] of Object.entries(policy.effective.env ?? {})) {
+    env[key] = value;
+  }
+}

src/native-subagents.ts

@@ -0,0 +1,739 @@
+import type { AcpSessionNotification, SubagentState } from "./acp-subagents.js";
+import { AIR_SUBAGENT_KEY, airExtensionMeta } from "./air-extension.js";
+
+export type NativeSubagent = {
+  sessionId: string;
+  parentSessionId: string;
+  parentToolUseId?: string;
+  name: string;
+  task: string;
+  /**
+   * The exact prompt of this generation, sent as `prompt` in
+   * `subagent_spawned`. It is absent when the adapter has no prompt.
+   */
+  prompt?: string;
+  announced?: boolean;
+  terminalState?: SubagentState;
+  /** Connection-local single-flight state; never serialized on the wire. */
+  announcePromise?: Promise<void>;
+  /** Connection-local single-flight state; never serialized on the wire. */
+  terminalPromise?: Promise<void>;
+};
+
+export type NativeSubagentSession = {
+  nativeSubagentsByTaskId?: Map<string, NativeSubagent>;
+  nativeSubagentTaskIdByToolUseId?: Map<string, string>;
+  nativeSubagentParentByToolUseId?: Map<string, string>;
+};
+
+type Publish = (notification: AcpSessionNotification) => Promise<void>;
+type Logger = { log(message: string): void };
+
+type TaskStarted = {
+  taskId: string;
+  toolUseId?: string | null;
+  subagentType?: unknown;
+  description?: unknown;
+  prompt?: unknown;
+};
+
+type SubagentIdentity = {
+  name?: string;
+  description?: string;
+  prompt?: string;
+  subagentType?: string;
+};
+
+const MAX_PENDING_PARENTS = 64;
+const MAX_PENDING_UPDATES = 256;
+const MAX_PENDING_UPDATES_PER_PARENT = 32;
+/** The number of child tool calls whose owning child session the runtime remembers. */
+const MAX_CHILD_TOOL_CALLS = 2048;
+
+/**
+ * Owns the connection-local native subagent registry and all ACP lifecycle
+ * ordering. The main agent only supplies SDK facts and delivers routed output.
+ */
+export class NativeSubagentRuntime {
+  readonly enabled: boolean;
+
+  private readonly children: Map<string, NativeSubagent>;
+  private readonly taskByToolUse: Map<string, string>;
+  private readonly parentByToolUse: Map<string, string>;
+  private readonly identityByToolUse = new Map<string, SubagentIdentity>();
+  private readonly controlByToolUse = new Map<string, AcpSessionNotification>();
+  private readonly childByParentToolUse = new Map<string, NativeSubagent>();
+  /**
+   * The child session of each tool call that went to a child session. A later
+   * update of that tool call can lose `parentToolUseId`, for example a progress
+   * beat after the child finished. It still belongs to the child session.
+   */
+  private readonly childByToolCall = new Map<string, NativeSubagent>();
+  private readonly taskFinishPromises = new Map<string, Promise<void>>();
+  private readonly generationByTaskId = new Map<string, number>();
+  private readonly pending = new Map<string, AcpSessionNotification[]>();
+  private pendingCount = 0;
+
+  constructor(
+    enabled: boolean,
+    private readonly rootSessionId: string,
+    private readonly session: NativeSubagentSession,
+    private readonly publish: Publish,
+    private readonly logger: Logger,
+  ) {
+    this.enabled = enabled;
+    this.children = session.nativeSubagentsByTaskId ??= new Map();
+    this.taskByToolUse = session.nativeSubagentTaskIdByToolUseId ??= new Map();
+    this.parentByToolUse = session.nativeSubagentParentByToolUseId ??= new Map();
+    for (const child of this.children.values()) {
+      if (child.parentToolUseId) {
+        this.childByParentToolUse.set(child.parentToolUseId, child);
+      }
+    }
+  }
+
+  async route(
+    notification: AcpSessionNotification,
+    deliver: Publish,
+    forcedSessionId?: string,
+  ): Promise<AcpSessionNotification | null> {
+    const { update } = notification;
+    const claudeMeta = update._meta?.claudeCode as
+      { parentToolUseId?: string | null; toolName?: string } | undefined;
+    const isControl = isNativeSubagentControlUpdate(update);
+
+    if (!this.enabled) return notification;
+
+    if (this.enabled && isControl) {
+      const toolCallId = update.toolCallId;
+      if (update.sessionUpdate === "tool_call") {
+        this.controlByToolUse.set(toolCallId, notification);
+      }
+      const identity = subagentIdentity(update.rawInput);
+      if (identity) {
+        this.identityByToolUse.set(
+          toolCallId,
+          mergeSubagentIdentity(this.identityByToolUse.get(toolCallId), identity),
+        );
+      }
+      const parentSessionId = claudeMeta?.parentToolUseId
+        ? this.childByParentToolUse.get(claudeMeta.parentToolUseId)?.sessionId
+        : this.rootSessionId;
+      this.parentByToolUse.set(toolCallId, parentSessionId ?? this.rootSessionId);
+
+      const child = this.childByParentToolUse.get(toolCallId);
+      if (child && !child.announced) {
+        child.parentSessionId = parentSessionId ?? this.rootSessionId;
+        applySubagentIdentity(child, this.identityByToolUse.get(toolCallId));
+        await announceNativeSubagent(child, this.publish);
+        for (const pending of this.takePending(toolCallId)) await deliver(pending);
+      }
+      if (!child && isFailedToolCallUpdate(update)) {
+        this.takePending(toolCallId);
+        const initial = this.controlByToolUse.get(toolCallId);
+        this.cleanupControl(toolCallId);
+        if (forcedSessionId) {
+          return { ...notification, sessionId: forcedSessionId };
+        }
+        return failedControlFallback(initial, notification, parentSessionId ?? this.rootSessionId);
+      }
+      return forcedSessionId ? { ...notification, sessionId: forcedSessionId } : null;
+    }
+
+    const toolCallId =
+      update.sessionUpdate === "tool_call" || update.sessionUpdate === "tool_call_update"
+        ? update.toolCallId
+        : undefined;
+
+    // A permission request may have had to create the tool call before native
+    // child ownership was known. Keep every later update in that original ACP
+    // session; moving a lifecycle after its initial call creates an orphan in
+    // both transcripts.
+    if (forcedSessionId) {
+      const forcedChild = this.childOfSession(forcedSessionId);
+      if (toolCallId && forcedChild) this.rememberToolCallOwner(toolCallId, forcedChild);
+      return { ...notification, sessionId: forcedSessionId };
+    }
+
+    const owner = toolCallId ? this.childByToolCall.get(toolCallId) : undefined;
+    if (owner) return this.toChild(owner, notification, toolCallId);
+
+    if (this.enabled && claudeMeta?.parentToolUseId) {
+      const child = this.childByParentToolUse.get(claudeMeta.parentToolUseId);
+      if (!child || !child.announced) {
+        this.buffer(claudeMeta.parentToolUseId, notification);
+        return null;
+      }
+      return this.toChild(child, notification, toolCallId);
+    }
+
+    return notification;
+  }
+
+  async taskStarted(task: TaskStarted, deliver: Publish): Promise<void> {
+    if (!this.enabled) return;
+    if (!task.subagentType) {
+      if (task.toolUseId) {
+        this.takePending(task.toolUseId);
+        this.cleanupControl(task.toolUseId);
+      }
+      return;
+    }
+    const previous = this.children.get(task.taskId);
+    if (previous && previous.terminalState === undefined) return;
+
+    // A SendMessage resume reuses the finished generation's tool id, whose
+    // control state is already cleaned up.
+    const knownParentSessionId =
+      (task.toolUseId ? this.parentByToolUse.get(task.toolUseId) : undefined) ??
+      (previous && this.resumedParentSessionId(previous));
+    const identity = task.toolUseId ? this.identityByToolUse.get(task.toolUseId) : undefined;
+    // A nested child must wait for the spawning Agent/Task frame to establish
+    // its immediate parent. Root children without a tool id can be announced.
+    await this.openGeneration(
+      task.taskId,
+      previous,
+      {
+        parentSessionId: knownParentSessionId ?? this.rootSessionId,
+        parentToolUseId: task.toolUseId ?? undefined,
+        name: subagentDisplayName(
+          identity?.name,
+          identity?.description ?? task.description,
+          identity?.subagentType ?? task.subagentType,
+          task.taskId,
+        ),
+        task: subagentDescription(
+          identity?.prompt ?? task.prompt,
+          identity?.description ?? task.description,
+        ),
+        ...promptField(promptText(task.prompt) ?? identity?.prompt),
+      },
+      !!knownParentSessionId || !task.toolUseId,
+      deliver,
+    );
+  }
+
+  /**
+   * Opens a new generation of a finished child when the SDK resumes the same
+   * agent id. The SDK can resume a child without a new `task_started`, so a
+   * running `task_updated` patch or a SendMessage `resumedAgentId` is the
+   * signal. A child that did not finish is not changed. The `prompt` is the
+   * SendMessage text that resumed the child, when the adapter knows it.
+   */
+  async taskResumed(taskId: string, deliver: Publish, prompt?: string): Promise<void> {
+    if (!this.enabled) return;
+    const previous = this.children.get(taskId);
+    if (!previous) return;
+    const finishing = this.taskFinishPromises.get(taskId) ?? previous.terminalPromise;
+    if (finishing) await finishing.catch(() => {});
+    if (this.children.get(taskId) !== previous || previous.terminalState === undefined) return;
+    await this.openGeneration(
+      taskId,
+      previous,
+      {
+        parentSessionId: this.resumedParentSessionId(previous),
+        parentToolUseId: previous.parentToolUseId,
+        name: previous.name,
+        task: previous.task,
+        ...promptField(promptText(prompt)),
+      },
+      true,
+      deliver,
+    );
+  }
+
+  async finishTask(
+    taskId: string,
+    status: unknown,
+    deliver: Publish,
+    toolUseId?: string | null,
+  ): Promise<void> {
+    if (!this.enabled) return;
+    const state = nativeSubagentState(status);
+    const child = toolUseId ? this.childByParentToolUse.get(toolUseId) : this.children.get(taskId);
+    if (child && toolUseId && this.taskByToolUse.get(toolUseId) !== taskId) return;
+    if (!state || !child || child.terminalState !== undefined) return;
+    const existing = this.taskFinishPromises.get(taskId);
+    if (existing) return existing;
+
+    const finish = Promise.resolve().then(async () => {
+      try {
+        await announceNativeSubagent(child, this.publish);
+        if (child.parentToolUseId) {
+          for (const pending of this.takePending(child.parentToolUseId)) await deliver(pending);
+        }
+        await finishNativeSubagent(this.session, taskId, state, this.publish);
+      } finally {
+        if (child.parentToolUseId) {
+          this.cleanupControl(child.parentToolUseId);
+        }
+      }
+    });
+    this.taskFinishPromises.set(taskId, finish);
+    try {
+      await finish;
+    } finally {
+      if (this.taskFinishPromises.get(taskId) === finish) this.taskFinishPromises.delete(taskId);
+    }
+  }
+
+  async finishAll(state: SubagentState, deliver: Publish): Promise<void> {
+    const errors: unknown[] = [];
+    try {
+      for (const taskId of [...this.children.keys()].reverse()) {
+        try {
+          await this.finishTask(taskId, state, deliver);
+        } catch (error) {
+          errors.push(error);
+        }
+      }
+    } finally {
+      this.pending.clear();
+      this.pendingCount = 0;
+      this.identityByToolUse.clear();
+      this.controlByToolUse.clear();
+      this.parentByToolUse.clear();
+    }
+    if (errors.length === 1) throw errors[0];
+    if (errors.length > 1) throw new AggregateError(errors, "Failed to finish native subagents");
+  }
+
+  discardPending(parentToolUseId: string): void {
+    this.takePending(parentToolUseId);
+  }
+
+  /**
+   * Routes an update to the child session. An update of a finished child is
+   * dropped: it never goes to the root session.
+   */
+  private toChild(
+    child: NativeSubagent,
+    notification: AcpSessionNotification,
+    toolCallId: string | undefined,
+  ): AcpSessionNotification | null {
+    if (child.terminalState !== undefined || child.terminalPromise) {
+      this.logger.log(
+        `Session ${this.rootSessionId}: ignoring late update for terminal subagent ${child.sessionId}`,
+      );
+      return null;
+    }
+    if (toolCallId) this.rememberToolCallOwner(toolCallId, child);
+    return { ...notification, sessionId: child.sessionId };
+  }
+
+  /**
+   * The route of the work that a child tool call started, for example an async
+   * task. The route sends each update to the child generation that owned the
+   * tool call when the work started, and drops the update after that child
+   * finished. `undefined` means that the root session owns the tool call.
+   * `eagerSessionId` is the session where a permission request created the
+   * tool call before the stream routed it.
+   */
+  routeOfToolCall(
+    toolCallId: string,
+    eagerSessionId?: string,
+  ): ((notification: AcpSessionNotification) => AcpSessionNotification | null) | undefined {
+    if (!this.enabled) return undefined;
+    const owner =
+      this.childByToolCall.get(toolCallId) ??
+      (eagerSessionId ? this.childOfSession(eagerSessionId) : undefined);
+    return owner && ((notification) => this.toChild(owner, notification, undefined));
+  }
+
+  private rememberToolCallOwner(toolCallId: string, child: NativeSubagent): void {
+    this.childByToolCall.delete(toolCallId);
+    this.childByToolCall.set(toolCallId, child);
+    if (this.childByToolCall.size > MAX_CHILD_TOOL_CALLS) {
+      const oldest = this.childByToolCall.keys().next().value;
+      if (oldest !== undefined) this.childByToolCall.delete(oldest);
+    }
+  }
+
+  /** The child generation with the ACP session `sessionId`, if one exists. */
+  private childOfSession(sessionId: string): NativeSubagent | undefined {
+    if (sessionId === this.rootSessionId) return undefined;
+    for (const child of this.children.values()) {
+      if (child.sessionId === sessionId) return child;
+    }
+    return undefined;
+  }
+
+  clear(): void {
+    this.children.clear();
+    this.childByToolCall.clear();
+    this.taskByToolUse.clear();
+    this.parentByToolUse.clear();
+    this.identityByToolUse.clear();
+    this.controlByToolUse.clear();
+    this.childByParentToolUse.clear();
+    this.taskFinishPromises.clear();
+    this.generationByTaskId.clear();
+    this.pending.clear();
+    this.pendingCount = 0;
+  }
+
+  private takePending(parentToolUseId: string): AcpSessionNotification[] {
+    const updates = this.pending.get(parentToolUseId) ?? [];
+    if (updates.length > 0) {
+      this.pending.delete(parentToolUseId);
+      this.pendingCount -= updates.length;
+    }
+    return updates;
+  }
+
+  private buffer(parentToolUseId: string, notification: AcpSessionNotification): void {
+    const updates = this.pending.get(parentToolUseId);
+    if (
+      this.pendingCount >= MAX_PENDING_UPDATES ||
+      (updates === undefined && this.pending.size >= MAX_PENDING_PARENTS) ||
+      (updates?.length ?? 0) >= MAX_PENDING_UPDATES_PER_PARENT
+    ) {
+      this.logger.log(
+        `Session ${this.rootSessionId}: dropping unattributed subagent update for ${parentToolUseId}; pending buffer limit reached`,
+      );
+      return;
+    }
+    if (updates) updates.push(notification);
+    else this.pending.set(parentToolUseId, [notification]);
+    this.pendingCount++;
+  }
+
+  private cleanupControl(toolUseId: string): void {
+    this.identityByToolUse.delete(toolUseId);
+    this.controlByToolUse.delete(toolUseId);
+    this.parentByToolUse.delete(toolUseId);
+  }
+
+  /** The parent of a resumed generation: the old parent while it is live, else the root. */
+  private resumedParentSessionId(previous: NativeSubagent): string {
+    return this.isLiveSession(previous.parentSessionId)
+      ? previous.parentSessionId
+      : this.rootSessionId;
+  }
+
+  private isLiveSession(sessionId: string): boolean {
+    if (sessionId === this.rootSessionId) return true;
+    for (const child of this.children.values()) {
+      if (child.sessionId === sessionId) return child.terminalState === undefined;
+    }
+    return false;
+  }
+
+  /**
+   * Registers a new child session for the task and makes it the owner of its
+   * parent tool call. With `announce`, it publishes `subagent_spawned` and
+   * delivers the updates that waited for the child.
+   */
+  private async openGeneration(
+    taskId: string,
+    previous: NativeSubagent | undefined,
+    fields: Pick<
+      NativeSubagent,
+      "parentSessionId" | "parentToolUseId" | "name" | "task" | "prompt"
+    >,
+    announce: boolean,
+    deliver: Publish,
+  ): Promise<void> {
+    const child: NativeSubagent = {
+      sessionId: this.nextChildSessionId(taskId, previous),
+      ...fields,
+    };
+    const toolUseId = child.parentToolUseId;
+    this.children.set(taskId, child);
+    if (toolUseId) {
+      this.taskByToolUse.set(toolUseId, taskId);
+      this.childByParentToolUse.set(toolUseId, child);
+      this.controlByToolUse.delete(toolUseId);
+    }
+    if (!announce) return;
+    await announceNativeSubagent(child, this.publish);
+    for (const pending of toolUseId ? this.takePending(toolUseId) : []) await deliver(pending);
+  }
+
+  private nextChildSessionId(taskId: string, previous: NativeSubagent | undefined): string {
+    if (!previous) {
+      this.generationByTaskId.set(taskId, 1);
+      return taskId;
+    }
+    const generation = (this.generationByTaskId.get(taskId) ?? 1) + 1;
+    this.generationByTaskId.set(taskId, generation);
+    return `${taskId}:generation:${generation}`;
+  }
+}
+
+export async function announceNativeSubagent(
+  child: NativeSubagent,
+  publish: Publish,
+): Promise<void> {
+  if (child.announced) return;
+  if (child.announcePromise) return child.announcePromise;
+  const announce = Promise.resolve().then(async () => {
+    await publish({
+      sessionId: child.parentSessionId,
+      update: {
+        sessionUpdate: "subagent_spawned",
+        subagentSessionId: child.sessionId,
+        name: child.name,
+        task: child.task,
+        ...promptField(child.prompt),
+        capabilities: {},
+      },
+    });
+    child.announced = true;
+  });
+  child.announcePromise = announce;
+  try {
+    await announce;
+  } finally {
+    if (child.announcePromise === announce) child.announcePromise = undefined;
+  }
+}
+
+export async function finishNativeSubagent(
+  session: NativeSubagentSession,
+  taskId: string,
+  state: SubagentState,
+  publish: Publish,
+): Promise<void> {
+  const child = session.nativeSubagentsByTaskId?.get(taskId);
+  if (!child || child.terminalState !== undefined) return;
+  if (child.terminalPromise) return child.terminalPromise;
+  const finish = Promise.resolve().then(async () => {
+    await announceNativeSubagent(child, publish);
+    await publish({
+      sessionId: child.parentSessionId,
+      update: {
+        sessionUpdate: "subagent_state_update",
+        subagentSessionId: child.sessionId,
+        state,
+      },
+    });
+    child.terminalState = state;
+  });
+  child.terminalPromise = finish;
+  try {
+    await finish;
+  } finally {
+    if (child.terminalPromise === finish) child.terminalPromise = undefined;
+  }
+}
+
+/**
+ * The agent id that a successful SendMessage result resumed. The SDK puts it
+ * in `tool_use_result.resumedAgentId` when a finished agent runs again.
+ */
+export function resumedNativeSubagentId(toolUseResult: unknown): string | undefined {
+  if (typeof toolUseResult !== "object" || toolUseResult === null) return undefined;
+  const result = toolUseResult as { success?: unknown; resumedAgentId?: unknown };
+  return result.success === true ? nonBlankString(result.resumedAgentId) : undefined;
+}
+
+/**
+ * The SendMessage text that resumed the agent `agentId`. The tool uses of
+ * `resultToolUseIds` come first: they are the SendMessage calls whose result
+ * carried the resume. Otherwise the latest SendMessage call to `agentId` counts.
+ */
+export function sendMessageResumePrompt(
+  toolUses: Record<string, { name: string; input: unknown } | undefined>,
+  agentId: string,
+  resultToolUseIds: readonly string[] = [],
+): string | undefined {
+  for (const toolUseId of resultToolUseIds) {
+    const toolUse = toolUses[toolUseId];
+    if (toolUse?.name !== "SendMessage") continue;
+    const text = promptText((toolUse.input as { message?: unknown } | null)?.message);
+    if (text) return text;
+  }
+  if (resultToolUseIds.length > 0) return undefined;
+  for (const toolUse of Object.values(toolUses).reverse()) {
+    if (toolUse?.name !== "SendMessage") continue;
+    const input = toolUse.input as { to?: unknown; message?: unknown } | null;
+    if (input?.to === agentId) return promptText(input.message);
+  }
+  return undefined;
+}
+
+export function nativeSubagentState(status: unknown): SubagentState | undefined {
+  if (status === "completed") return "completed";
+  if (status === "failed") return "failed";
+  if (status === "disconnected") return "disconnected";
+  if (status === "killed" || status === "cancelled" || status === "stopped") return "cancelled";
+  return undefined;
+}
+
+export function isNativeSubagentControlUpdate(
+  update: AcpSessionNotification["update"],
+): update is Extract<
+  AcpSessionNotification["update"],
+  { sessionUpdate: "tool_call" | "tool_call_update" }
+> {
+  if (update.sessionUpdate !== "tool_call" && update.sessionUpdate !== "tool_call_update") {
+    return false;
+  }
+  const claudeMeta = update._meta?.claudeCode as { toolName?: string } | undefined;
+  return (
+    airExtensionMeta(update._meta)?.[AIR_SUBAGENT_KEY] === true ||
+    isNativeSubagentControlTool(claudeMeta?.toolName)
+  );
+}
+
+export function isNativeSubagentControlTool(toolName: unknown): boolean {
+  return toolName === "Agent" || toolName === "Task";
+}
+
+function isFailedToolCallUpdate(update: AcpSessionNotification["update"]): boolean {
+  return (
+    (update.sessionUpdate === "tool_call" || update.sessionUpdate === "tool_call_update") &&
+    update.status === "failed"
+  );
+}
+
+function failedControlFallback(
+  initial: AcpSessionNotification | undefined,
+  terminal: AcpSessionNotification,
+  sessionId: string,
+): AcpSessionNotification {
+  if (
+    terminal.update.sessionUpdate !== "tool_call" &&
+    terminal.update.sessionUpdate !== "tool_call_update"
+  ) {
+    return { ...terminal, sessionId };
+  }
+  if (!initial || initial.update.sessionUpdate !== "tool_call") {
+    const claudeMeta = terminal.update._meta?.claudeCode as { toolName?: unknown } | undefined;
+    return {
+      ...terminal,
+      sessionId,
+      update: {
+        ...terminal.update,
+        sessionUpdate: "tool_call",
+        status: "failed",
+        // The synthesized tool_call is this call's first report, so give it
+        // the standard `name` the initial one would have carried.
+        ...(typeof claudeMeta?.toolName === "string" ? { name: claudeMeta.toolName } : {}),
+        title:
+          typeof terminal.update.title === "string" && terminal.update.title.length > 0
+            ? terminal.update.title
+            : claudeMeta?.toolName === "Task"
+              ? "Task"
+              : "Agent",
+        _meta: ordinaryToolMeta(terminal.update._meta),
+      } as AcpSessionNotification["update"],
+    };
+  }
+  return {
+    ...initial,
+    sessionId,
+    update: {
+      ...initial.update,
+      ...terminal.update,
+      sessionUpdate: "tool_call",
+      status: "failed",
+      title:
+        typeof terminal.update.title === "string" && terminal.update.title.trim().length > 0
+          ? terminal.update.title
+          : initial.update.title,
+      _meta: {
+        ...initial.update._meta,
+        ...terminal.update._meta,
+        ...ordinaryToolMeta(initial.update._meta, terminal.update._meta),
+      },
+    } as AcpSessionNotification["update"],
+  };
+}
+
+function ordinaryToolMeta(
+  ...values: Array<Record<string, unknown> | null | undefined>
+): Record<string, unknown> {
+  const merged = Object.assign({}, ...values);
+  const claudeCode = Object.assign(
+    {},
+    ...values.map(
+      (value) => (value?.claudeCode as Record<string, unknown> | null | undefined) ?? {},
+    ),
+  );
+  const result: Record<string, unknown> = { ...merged, claudeCode };
+  const air = airExtensionMeta(merged);
+  if (air && AIR_SUBAGENT_KEY in air) {
+    const rest = { ...air };
+    delete rest[AIR_SUBAGENT_KEY];
+    result.jetbrains = { ...(merged.jetbrains as Record<string, unknown>), air: rest };
+  }
+  return result;
+}
+
+function subagentDisplayName(
+  explicitName: unknown,
+  description: unknown,
+  type: unknown,
+  taskId: string,
+): string {
+  for (const value of [explicitName, description, type]) {
+    if (typeof value === "string" && value.trim().length > 0) return value.trim();
+  }
+  const suffix = taskId.length > 8 ? taskId.slice(-8) : taskId;
+  return `Agent ${suffix}`;
+}
+
+function subagentDescription(prompt: unknown, description: unknown): string {
+  for (const value of [prompt, description]) {
+    if (typeof value === "string" && value.trim().length > 0) return value.trim();
+  }
+  return "Delegated task";
+}
+
+function subagentIdentity(input: unknown): SubagentIdentity | undefined {
+  if (typeof input !== "object" || input === null || Array.isArray(input)) return undefined;
+  const value = input as Record<string, unknown>;
+  const identity: SubagentIdentity = {
+    name: nonBlankString(value.name),
+    description: nonBlankString(value.description),
+    prompt: promptText(value.prompt),
+    subagentType: nonBlankString(value.subagent_type),
+  };
+  return Object.values(identity).some(Boolean) ? identity : undefined;
+}
+
+function mergeSubagentIdentity(
+  previous: SubagentIdentity | undefined,
+  next: SubagentIdentity,
+): SubagentIdentity {
+  return {
+    name: next.name ?? previous?.name,
+    description: next.description ?? previous?.description,
+    prompt: next.prompt ?? previous?.prompt,
+    subagentType: next.subagentType ?? previous?.subagentType,
+  };
+}
+
+function applySubagentIdentity(
+  child: NativeSubagent,
+  identity: SubagentIdentity | undefined,
+): void {
+  if (!identity) return;
+  if (identity.name || identity.description) {
+    child.name = subagentDisplayName(
+      identity.name,
+      identity.description,
+      identity.subagentType,
+      child.sessionId,
+    );
+  }
+  if (identity.prompt || identity.description) {
+    child.task = subagentDescription(identity.prompt, identity.description);
+  }
+  child.prompt ??= identity.prompt;
+}
+
+/** The prompt text unchanged, or `undefined` when it is not a non-blank string. */
+function promptText(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim().length > 0 ? value : undefined;
+}
+
+function promptField(prompt: string | undefined): { prompt?: string } {
+  return prompt === undefined ? {} : { prompt };
+}
+
+function nonBlankString(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim().length > 0 ? value.trim() : undefined;
+}

src/paths.ts

@@ -0,0 +1,7 @@
+import * as os from "node:os";
+import * as path from "node:path";
+
+/** The Claude configuration directory: `CLAUDE_CONFIG_DIR`, or `~/.claude`. */
+export function claudeConfigDir(): string {
+  return process.env.CLAUDE_CONFIG_DIR ?? path.join(os.homedir(), ".claude");
+}

src/permissions/effects.ts

@@ -0,0 +1,223 @@
+import type { RequestPermissionResponse } from "@agentclientprotocol/sdk";
+import type {
+  PermissionMode,
+  PermissionResult,
+  PermissionUpdate,
+} from "@anthropic-ai/claude-agent-sdk";
+import type { DurablePermissionChangeSet } from "./normalization.js";
+import { PERMISSION_OPTION_ID } from "./options.js";
+
+export interface ClaudePermissionSelection {
+  optionId: string;
+  contextResetMode?: PermissionMode;
+}
+
+export interface ClaudePermissionEffectContext {
+  toolName: string;
+  input: Record<string, unknown>;
+  toolUseID: string;
+  durableChangeSet?: DurablePermissionChangeSet;
+}
+
+/** Parse the ACP envelope once before dispatching to a tool-specific effect. */
+export function parseClaudePermissionSelection(
+  response: RequestPermissionResponse,
+  toolName: string,
+): ClaudePermissionSelection {
+  if (response.outcome?.outcome !== "selected") throw new Error("Tool use aborted");
+  const optionId = response.outcome.optionId;
+  const contextResetMode =
+    toolName === "ExitPlanMode" ? exitPlanClearContextMode(optionId) : undefined;
+  return { optionId, ...(contextResetMode ? { contextResetMode } : {}) };
+}
+
+function allow(
+  context: ClaudePermissionEffectContext,
+  updatedPermissions?: PermissionUpdate[],
+  permanent = false,
+): PermissionResult {
+  return {
+    behavior: "allow",
+    updatedInput: context.input,
+    ...(updatedPermissions ? { updatedPermissions } : {}),
+    toolUseID: context.toolUseID,
+    decisionClassification: permanent ? "user_permanent" : "user_temporary",
+  };
+}
+
+function deny(
+  context: ClaudePermissionEffectContext,
+  message = "User refused permission to run tool",
+  interrupt = false,
+): PermissionResult {
+  return {
+    behavior: "deny",
+    message,
+    ...(interrupt ? { interrupt: true } : {}),
+    toolUseID: context.toolUseID,
+    decisionClassification: "user_reject",
+  };
+}
+
+function skillName(input: Record<string, unknown>): string {
+  const value = typeof input.skill === "string" ? input.skill.trim() : "";
+  if (!value || value.length > 1_000) throw new Error("Invalid Skill permission input");
+  return value;
+}
+
+function localAllowRuleUpdate(toolName: string, ruleContent?: string): PermissionUpdate[] {
+  return [
+    {
+      type: "addRules",
+      rules: [{ toolName, ...(ruleContent === undefined ? {} : { ruleContent }) }],
+      behavior: "allow",
+      destination: "localSettings",
+    },
+  ];
+}
+
+function webFetchPermissionUpdate(input: Record<string, unknown>): PermissionUpdate[] {
+  if (typeof input.url !== "string") throw new Error("Invalid WebFetch permission input");
+  let hostname: string;
+  try {
+    hostname = new URL(input.url).hostname;
+  } catch {
+    throw new Error("Invalid WebFetch permission input");
+  }
+  if (!hostname) throw new Error("Invalid WebFetch permission input");
+  return localAllowRuleUpdate("WebFetch", `domain:${hostname}`);
+}
+
+function applySkillSelection(
+  selection: ClaudePermissionSelection,
+  context: ClaudePermissionEffectContext,
+): PermissionResult {
+  switch (selection.optionId) {
+    case PERMISSION_OPTION_ID.allowSkillExact: {
+      return allow(context, localAllowRuleUpdate("Skill", skillName(context.input)), true);
+    }
+    case PERMISSION_OPTION_ID.allowSkillPrefix: {
+      const skill = skillName(context.input);
+      const spaceIndex = skill.indexOf(" ");
+      if (spaceIndex <= 0) throw new Error("Skill prefix permission requires arguments");
+      return allow(context, localAllowRuleUpdate("Skill", `${skill.slice(0, spaceIndex)}:*`), true);
+    }
+    default:
+      return applyCommonSelection(selection, context);
+  }
+}
+
+function exitPlanMode(optionId: string): PermissionMode | undefined {
+  switch (optionId) {
+    case PERMISSION_OPTION_ID.exitPlanBypass:
+      return "bypassPermissions";
+    case PERMISSION_OPTION_ID.exitPlanAuto:
+      return "auto";
+    case PERMISSION_OPTION_ID.exitPlanAcceptEdits:
+      return "acceptEdits";
+    case PERMISSION_OPTION_ID.exitPlanDefault:
+      return "default";
+    default:
+      return undefined;
+  }
+}
+
+export function exitPlanClearContextMode(optionId: string): PermissionMode | undefined {
+  switch (optionId) {
+    case PERMISSION_OPTION_ID.exitPlanClearAuto:
+      return "auto";
+    case PERMISSION_OPTION_ID.exitPlanClearBypass:
+      return "bypassPermissions";
+    case PERMISSION_OPTION_ID.exitPlanClearAcceptEdits:
+      return "acceptEdits";
+    default:
+      return undefined;
+  }
+}
+
+function applyExitPlanModeSelection(
+  selection: ClaudePermissionSelection,
+  context: ClaudePermissionEffectContext,
+): PermissionResult {
+  if (selection.contextResetMode) {
+    // The adapter consumes this interrupt and continues the same ACP turn on a
+    // fresh Claude query. Returning allow here would execute ExitPlanMode in
+    // the old context before the handoff.
+    return deny(context, "User accepted the plan and requested a fresh context", true);
+  }
+  const mode = exitPlanMode(selection.optionId);
+  if (mode) {
+    return allow(context, [{ type: "setMode", mode, destination: "session" }], mode !== "default");
+  }
+  if (selection.optionId === PERMISSION_OPTION_ID.reject) {
+    // A regular deny lets Claude continue planning and ask another question.
+    // Interrupt stops this ACP turn; the adapter maps Claude's internal
+    // diagnostic for that intentional stop back to cancellation.
+    return deny(context, "User chose to keep planning", true);
+  }
+  return applyCommonSelection(selection, context);
+}
+
+function applyCommonSelection(
+  selection: ClaudePermissionSelection,
+  context: ClaudePermissionEffectContext,
+): PermissionResult {
+  switch (selection.optionId) {
+    case PERMISSION_OPTION_ID.allowOnce:
+      return allow(context);
+    case PERMISSION_OPTION_ID.allowWithUpdates:
+      if (!context.durableChangeSet) throw new Error("Invalid durable permission selection");
+      return allow(context, context.durableChangeSet.updates, true);
+    case PERMISSION_OPTION_ID.reject:
+      return deny(context);
+    default:
+      throw new Error(`Unknown permission option: ${selection.optionId}`);
+  }
+}
+
+function applyGeneratedDurableSelection(
+  selection: ClaudePermissionSelection,
+  context: ClaudePermissionEffectContext,
+  updates: () => PermissionUpdate[],
+): PermissionResult {
+  if (selection.optionId !== PERMISSION_OPTION_ID.allowWithUpdates) {
+    return applyCommonSelection(selection, context);
+  }
+  return allow(context, updates(), true);
+}
+
+/** Apply a parsed selection using the semantics of the tool that produced it. */
+export function applyClaudePermissionSelection(
+  selection: ClaudePermissionSelection,
+  context: ClaudePermissionEffectContext,
+): PermissionResult {
+  switch (context.toolName) {
+    case "Skill":
+      return applySkillSelection(selection, context);
+    case "WebFetch":
+      return applyGeneratedDurableSelection(selection, context, () =>
+        webFetchPermissionUpdate(context.input),
+      );
+    case "EnterPlanMode":
+      return applyCommonSelection(selection, context);
+    case "ExitPlanMode":
+      return applyExitPlanModeSelection(selection, context);
+    case "Read":
+    case "Bash":
+    case "PowerShell":
+    case "Glob":
+    case "Grep":
+    case "Edit":
+    case "Write":
+    case "NotebookEdit":
+    case "SandboxNetworkAccess":
+      return applyCommonSelection(selection, context);
+    default:
+      if (context.toolName.startsWith("mcp__")) {
+        return applyCommonSelection(selection, context);
+      }
+      return applyGeneratedDurableSelection(selection, context, () =>
+        localAllowRuleUpdate(context.toolName),
+      );
+  }
+}

src/permissions/modes.ts

@@ -0,0 +1,60 @@
+import type { PermissionMode } from "@anthropic-ai/claude-agent-sdk";
+
+interface PermissionModeLogger {
+  error: (...args: unknown[]) => void;
+}
+
+// Bypass Permissions doesn't work if we are a root/sudo user.
+const IS_ROOT = (process.geteuid?.() ?? process.getuid?.()) === 0;
+export const ALLOW_BYPASS = !IS_ROOT || !!process.env.IS_SANDBOX;
+
+const PERMISSION_MODE_ALIASES: Record<string, PermissionMode> = {
+  // Settings use user-facing, case-insensitive spellings while the SDK uses
+  // camel-cased wire values. Keep legacy shorthand accepted by Claude Code too.
+  auto: "auto",
+  default: "default",
+  // Claude Code 2.1.200 renamed the "default" mode to "Manual" and accepts
+  // `"defaultMode": "manual"` in settings.json; honor the same alias here.
+  manual: "default",
+  acceptedits: "acceptEdits",
+  dontask: "dontAsk",
+  plan: "plan",
+  bypasspermissions: "bypassPermissions",
+  bypass: "bypassPermissions",
+};
+
+/** When `allowBypass` is false, `bypassPermissions` clamps to `default` so the SDK
+ *  is never spawned in a mode it would reject. */
+export function resolvePermissionMode(
+  defaultMode?: unknown,
+  logger: PermissionModeLogger = console,
+  allowBypass: boolean = ALLOW_BYPASS,
+): PermissionMode {
+  if (defaultMode === undefined) {
+    return "default";
+  }
+
+  if (typeof defaultMode !== "string") {
+    logger.error("Ignoring permissions.defaultMode from settings: expected a string.");
+    return "default";
+  }
+
+  const normalized = defaultMode.trim().toLowerCase();
+  if (normalized === "") {
+    logger.error("Ignoring permissions.defaultMode from settings: expected a non-empty string.");
+    return "default";
+  }
+
+  const mapped = PERMISSION_MODE_ALIASES[normalized];
+  if (!mapped) {
+    logger.error(`Ignoring permissions.defaultMode from settings: unknown value '${defaultMode}'.`);
+    return "default";
+  }
+
+  if (mapped === "bypassPermissions" && !allowBypass) {
+    logger.error("Ignoring permission mode bypassPermissions: not available in this session.");
+    return "default";
+  }
+
+  return mapped;
+}

src/permissions/normalization.ts

@@ -0,0 +1,130 @@
+import type {
+  PermissionBehavior,
+  PermissionMode,
+  PermissionUpdate,
+  PermissionUpdateDestination,
+} from "@anthropic-ai/claude-agent-sdk";
+
+export interface DurablePermissionChangeSet {
+  updates: PermissionUpdate[];
+}
+
+const MAX_UPDATES = 100;
+const MAX_RULES_PER_UPDATE = 100;
+const MAX_DIRECTORIES_PER_UPDATE = 100;
+const MAX_TOOL_NAME_LENGTH = 512;
+const MAX_RULE_CONTENT_LENGTH = 10_000;
+const MAX_DIRECTORY_LENGTH = 4_096;
+
+const DESTINATIONS = new Set<PermissionUpdateDestination>([
+  "session",
+  "cliArg",
+  "userSettings",
+  "projectSettings",
+  "localSettings",
+]);
+const BEHAVIORS = new Set<PermissionBehavior>(["allow", "deny", "ask"]);
+const MODES = new Set<PermissionMode>([
+  "default",
+  "acceptEdits",
+  "bypassPermissions",
+  "plan",
+  "dontAsk",
+  "auto",
+]);
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return !!value && typeof value === "object" && !Array.isArray(value);
+}
+
+function isDestination(value: unknown): value is PermissionUpdateDestination {
+  return typeof value === "string" && DESTINATIONS.has(value as PermissionUpdateDestination);
+}
+
+function safePlainString(value: unknown, maxLength: number): value is string {
+  if (typeof value !== "string") return false;
+  const normalized = value.trim();
+  return (
+    normalized.length > 0 &&
+    value.length <= maxLength &&
+    !Array.from(normalized).some((character) => {
+      const code = character.charCodeAt(0);
+      return (
+        code <= 0x08 ||
+        code === 0x0b ||
+        code === 0x0c ||
+        (code >= 0x0e && code <= 0x1f) ||
+        code === 0x7f
+      );
+    })
+  );
+}
+
+function isRule(value: unknown): value is { toolName: string; ruleContent?: string } {
+  if (!isRecord(value) || !safePlainString(value.toolName, MAX_TOOL_NAME_LENGTH)) {
+    return false;
+  }
+  return (
+    value.ruleContent === undefined || safePlainString(value.ruleContent, MAX_RULE_CONTENT_LENGTH)
+  );
+}
+
+function isKnownUpdate(value: unknown): value is PermissionUpdate {
+  if (!isRecord(value) || !isDestination(value.destination) || typeof value.type !== "string") {
+    return false;
+  }
+  switch (value.type) {
+    case "addRules":
+    case "replaceRules":
+    case "removeRules":
+      return (
+        Array.isArray(value.rules) &&
+        value.rules.length <= MAX_RULES_PER_UPDATE &&
+        (value.type === "replaceRules" || value.rules.length > 0) &&
+        value.rules.every(isRule) &&
+        typeof value.behavior === "string" &&
+        BEHAVIORS.has(value.behavior as PermissionBehavior)
+      );
+    case "setMode":
+      return typeof value.mode === "string" && MODES.has(value.mode as PermissionMode);
+    case "addDirectories":
+    case "removeDirectories":
+      return (
+        Array.isArray(value.directories) &&
+        value.directories.length > 0 &&
+        value.directories.length <= MAX_DIRECTORIES_PER_UPDATE &&
+        value.directories.every((directory) => safePlainString(directory, MAX_DIRECTORY_LENGTH))
+      );
+    default:
+      return false;
+  }
+}
+
+export function normalizeDurablePermissionChangeSet(
+  suggestions: unknown,
+  forcedAsk = false,
+): DurablePermissionChangeSet | undefined {
+  if (forcedAsk) return undefined;
+  try {
+    if (
+      !Array.isArray(suggestions) ||
+      suggestions.length === 0 ||
+      suggestions.length > MAX_UPDATES ||
+      !suggestions.every(isKnownUpdate)
+    ) {
+      return undefined;
+    }
+    return {
+      // The ACP prompt may stay open for an arbitrary amount of time. Snapshot the
+      // provider payload so the label the user approved and the effect returned to
+      // Claude cannot diverge through later mutation of the callback argument.
+      updates: structuredClone(suggestions as PermissionUpdate[]),
+    };
+  } catch {
+    // SDK data is expected to be plain structured-cloneable input. Treat an
+    // accessor, function, proxy, or other non-wire value as an invalid bundle.
+    // Validation belongs in this boundary too because merely reading one of those
+    // values can throw before structuredClone gets a chance to reject it.
+    return undefined;
+  }
+}

src/permissions/options.ts

@@ -0,0 +1,100 @@
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import {
+  buildEditPermissionOptions,
+  buildGlobPermissionOptions,
+  buildGrepPermissionOptions,
+  buildNotebookEditPermissionOptions,
+  buildReadPermissionOptions,
+  buildWritePermissionOptions,
+} from "./options/filesystem.js";
+import { buildBashPermissionOptions, buildPowerShellPermissionOptions } from "./options/shell.js";
+import type { PermissionOptionContext } from "./options/shared.js";
+import {
+  buildComputerUseMcpPermissionOptions,
+  buildEnterPlanModePermissionOptions,
+  buildExitPlanModePermissionOptions,
+  buildFallbackPermissionOptions,
+  buildSandboxNetworkPermissionOptions,
+  buildSkillPermissionOptions,
+  buildWebFetchPermissionOptions,
+  isComputerUseMcpTool,
+} from "./options/tools.js";
+
+export { PERMISSION_OPTION_ID } from "./options/shared.js";
+
+export function buildClaudePermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  // ACP has no "pre-selected option" field, so option order is the only lever
+  // for the CLI's `defaultToNo` hint ("open on the decline option"): lead with
+  // the reject options instead of the approvals.
+  const order = context.defaultToNo === true ? declineFirstOptionOrder : permissionOptionOrder;
+  return buildUnsortedClaudePermissionOptions(context).sort(
+    (left, right) => order(left) - order(right),
+  );
+}
+
+function buildUnsortedClaudePermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  if (isComputerUseMcpTool(context.toolName)) {
+    return buildComputerUseMcpPermissionOptions(context);
+  }
+  switch (context.toolName) {
+    case "AskUserQuestion":
+      throw new Error("AskUserQuestion must be handled by ACP elicitation, not permission options");
+    case "Bash":
+      return buildBashPermissionOptions(context);
+    case "PowerShell":
+      return buildPowerShellPermissionOptions(context);
+    case "Read":
+      return buildReadPermissionOptions(context);
+    case "Glob":
+      return buildGlobPermissionOptions(context);
+    case "Grep":
+      return buildGrepPermissionOptions(context);
+    case "Edit":
+      return buildEditPermissionOptions(context);
+    case "Write":
+      return buildWritePermissionOptions(context);
+    case "NotebookEdit":
+      return buildNotebookEditPermissionOptions(context);
+    case "WebFetch":
+      return buildWebFetchPermissionOptions(context);
+    case "Skill":
+      return buildSkillPermissionOptions(context);
+    case "EnterPlanMode":
+      return buildEnterPlanModePermissionOptions();
+    case "ExitPlanMode":
+      return buildExitPlanModePermissionOptions(context);
+    case "SandboxNetworkAccess":
+      return buildSandboxNetworkPermissionOptions(context);
+    case "WebSearch":
+    case "Agent":
+    case "Task":
+    default:
+      return buildFallbackPermissionOptions(context);
+  }
+}
+
+function declineFirstOptionOrder(option: PermissionOption): number {
+  switch (option.kind) {
+    case "reject_once":
+    case "reject_always":
+      return 0;
+    default:
+      return 1 + permissionOptionOrder(option);
+  }
+}
+
+function permissionOptionOrder(option: PermissionOption): number {
+  switch (option.kind) {
+    case "allow_once":
+      return 0;
+    case "allow_always":
+      return 1;
+    case "reject_once":
+    case "reject_always":
+      return 3;
+    default:
+      return 2;
+  }
+}

src/permissions/options/filesystem.ts

@@ -0,0 +1,186 @@
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import os from "node:os";
+import path from "node:path";
+import type { DurablePermissionChangeSet } from "../normalization.js";
+import { plainString, type PermissionOptionContext, withOptionalUpdate } from "./shared.js";
+
+function isFileSessionChangeSet(
+  changeSet: DurablePermissionChangeSet | undefined,
+  operation: "read" | "write",
+): boolean {
+  return (
+    !!changeSet &&
+    changeSet.updates.every((update) => {
+      if (update.destination !== "session") return false;
+      if (update.type === "setMode") {
+        return operation === "write" && update.mode === "acceptEdits";
+      }
+      if (update.type === "addDirectories") return operation === "write";
+      if (update.type !== "addRules" || update.behavior !== "allow") return false;
+      return update.rules.every((rule) =>
+        operation === "read" ? rule.toolName === "Read" : rule.toolName === "Edit",
+      );
+    })
+  );
+}
+
+function inputPath(context: PermissionOptionContext, key: string): string | undefined {
+  return plainString(context.input[key]);
+}
+
+function isInside(directory: string, candidate: string): boolean {
+  const relative = path.relative(path.resolve(directory), path.resolve(candidate));
+  return relative === "" || (!relative.startsWith(`..${path.sep}`) && relative !== "..");
+}
+
+function hasSessionAllowRuleFor(
+  changeSet: DurablePermissionChangeSet | undefined,
+  toolName: string,
+): boolean {
+  return !!changeSet?.updates.some(
+    (update) =>
+      update.type === "addRules" &&
+      update.destination === "session" &&
+      update.behavior === "allow" &&
+      update.rules.some((rule) => rule.toolName === toolName),
+  );
+}
+
+function hasBroadSessionAllowRuleFor(
+  changeSet: DurablePermissionChangeSet,
+  toolName: string,
+): boolean {
+  return changeSet.updates.some(
+    (update) =>
+      update.type === "addRules" &&
+      update.destination === "session" &&
+      update.behavior === "allow" &&
+      update.rules.some((rule) => rule.toolName === toolName && rule.ruleContent === undefined),
+  );
+}
+
+function hasAcceptEditsMode(changeSet: DurablePermissionChangeSet): boolean {
+  return changeSet.updates.some(
+    (update) =>
+      update.type === "setMode" &&
+      update.destination === "session" &&
+      update.mode === "acceptEdits",
+  );
+}
+
+function permissionPath(ruleContent: string | undefined): string | undefined {
+  const value = plainString(ruleContent);
+  if (!value) return undefined;
+  return value.replace(/[/\\]\*\*$/, "");
+}
+
+function effectCoversFilePath(
+  changeSet: DurablePermissionChangeSet,
+  filePath: string,
+  operation: "read" | "write",
+  cwd: string,
+): boolean {
+  const directory = path.dirname(filePath);
+  const comparable = (candidate: string): boolean => {
+    const resolved = path.resolve(cwd, candidate);
+    return resolved === directory || isInside(resolved, filePath);
+  };
+  const paths = changeSet.updates.flatMap((update) => {
+    if (update.type === "addDirectories") return update.directories;
+    if (update.type !== "addRules" || update.behavior !== "allow") return [];
+    return update.rules
+      .filter((rule) =>
+        operation === "read" ? rule.toolName === "Read" : rule.toolName === "Edit",
+      )
+      .map((rule) => permissionPath(rule.ruleContent))
+      .filter((value): value is string => value !== undefined);
+  });
+  return paths.some(comparable);
+}
+
+function fileSessionLabel(
+  context: PermissionOptionContext,
+  filePath: string | undefined,
+  operation: "read" | "write",
+): string | undefined {
+  if (!isFileSessionChangeSet(context.durableChangeSet, operation)) return undefined;
+  const resolvedFilePath = filePath ? path.resolve(context.cwd, filePath) : undefined;
+  const isClaudePath =
+    operation === "write" &&
+    !!resolvedFilePath &&
+    (isInside(path.join(context.cwd, ".claude"), resolvedFilePath) ||
+      isInside(path.join(os.homedir(), ".claude"), resolvedFilePath));
+  const broadRule = hasBroadSessionAllowRuleFor(
+    context.durableChangeSet!,
+    operation === "read" ? "Read" : "Edit",
+  );
+  if (resolvedFilePath) {
+    const coversCurrentPath =
+      effectCoversFilePath(context.durableChangeSet!, resolvedFilePath, operation, context.cwd) ||
+      broadRule ||
+      (operation === "write" && !isClaudePath && hasAcceptEditsMode(context.durableChangeSet!));
+    if (!coversCurrentPath) return undefined;
+  } else if (
+    !broadRule &&
+    !(operation === "write" && hasAcceptEditsMode(context.durableChangeSet!))
+  ) {
+    return undefined;
+  }
+  if (
+    operation === "write" &&
+    resolvedFilePath &&
+    isClaudePath &&
+    hasSessionAllowRuleFor(context.durableChangeSet, "Edit")
+  ) {
+    return "Yes, and allow Claude to edit its own settings for this session";
+  }
+  if (!resolvedFilePath || isInside(context.cwd, resolvedFilePath)) {
+    return operation === "read"
+      ? "Yes, during this session"
+      : "Yes, allow all edits during this session";
+  }
+  const directory = path.dirname(resolvedFilePath);
+  const directoryName = path.basename(directory) || "this directory";
+  return operation === "read"
+    ? `Yes, allow reading from ${directoryName}${path.sep} during this session`
+    : `Yes, allow all edits in ${directoryName}${path.sep} during this session`;
+}
+
+function buildFilePermissionOptions(
+  context: PermissionOptionContext,
+  filePath: string | undefined,
+  operation: "read" | "write",
+): PermissionOption[] {
+  return withOptionalUpdate(
+    context.durableChangeSet,
+    fileSessionLabel(context, filePath, operation),
+    "Yes",
+    "No",
+  );
+}
+
+export function buildReadPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "file_path"), "read");
+}
+
+export function buildGlobPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "path") ?? context.cwd, "read");
+}
+
+export function buildGrepPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "path") ?? context.cwd, "read");
+}
+
+export function buildEditPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "file_path"), "write");
+}
+
+export function buildWritePermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "file_path"), "write");
+}
+
+export function buildNotebookEditPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  return buildFilePermissionOptions(context, inputPath(context, "notebook_path"), "write");
+}

src/permissions/options/shared.ts

@@ -0,0 +1,110 @@
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import type { DurablePermissionChangeSet } from "../normalization.js";
+
+export const PERMISSION_OPTION_ID = {
+  allowOnce: "allow-once",
+  allowWithUpdates: "allow-with-updates",
+  allowSkillExact: "allow-skill-exact",
+  allowSkillPrefix: "allow-skill-prefix",
+  exitPlanBypass: "exit-plan-bypass",
+  exitPlanAuto: "exit-plan-auto",
+  exitPlanAcceptEdits: "exit-plan-accept-edits",
+  exitPlanDefault: "exit-plan-default",
+  exitPlanClearAuto: "exit-plan-clear-auto",
+  exitPlanClearBypass: "exit-plan-clear-bypass",
+  exitPlanClearAcceptEdits: "exit-plan-clear-accept-edits",
+  reject: "reject",
+} as const;
+
+export interface PermissionOptionContext {
+  toolName: string;
+  displayName?: string;
+  input: Record<string, unknown>;
+  cwd: string;
+  durableChangeSet?: DurablePermissionChangeSet;
+  allowPersistentOptions?: boolean;
+  /** The CLI's `defaultToNo` hint (SDK 0.3.268+): the ask must not be
+   *  approvable by a stray keystroke, so the decline option leads. */
+  defaultToNo?: boolean;
+  availableModes?: readonly string[];
+  /** The mode the session left when it entered plan mode. */
+  prePlanMode?: string;
+  contextUsedPercent?: number;
+}
+
+export function allowOnce(name = "Yes"): PermissionOption {
+  return { optionId: PERMISSION_OPTION_ID.allowOnce, name, kind: "allow_once" };
+}
+
+export function allowWithUpdates(name: string): PermissionOption {
+  return { optionId: PERMISSION_OPTION_ID.allowWithUpdates, name, kind: "allow_always" };
+}
+
+export function reject(name = "No"): PermissionOption {
+  return { optionId: PERMISSION_OPTION_ID.reject, name, kind: "reject_once" };
+}
+
+export function withOptionalUpdate(
+  changeSet: DurablePermissionChangeSet | undefined,
+  updateName: string | undefined,
+  allowName = "Yes",
+  rejectName = "No",
+): PermissionOption[] {
+  const options = [allowOnce(allowName)];
+  if (changeSet && updateName) options.push(allowWithUpdates(updateName));
+  options.push(reject(rejectName));
+  return options;
+}
+
+export function plainString(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim() ? value.trim() : undefined;
+}
+
+export function exactLocalAllowRule(
+  changeSet: DurablePermissionChangeSet | undefined,
+  toolName: string,
+  ruleContent?: string,
+): boolean {
+  if (!changeSet || changeSet.updates.length !== 1) return false;
+  const update = changeSet.updates[0];
+  if (
+    update?.type !== "addRules" ||
+    update.behavior !== "allow" ||
+    update.destination !== "localSettings" ||
+    update.rules.length !== 1
+  ) {
+    return false;
+  }
+  const rule = update.rules[0];
+  return (
+    rule?.toolName === toolName &&
+    (ruleContent === undefined
+      ? rule.ruleContent === undefined
+      : plainString(rule.ruleContent) === ruleContent)
+  );
+}
+
+/**
+ * An MCP "don't ask again" option is only truthful when every provider update
+ * adds an unrestricted allow rule for the tool currently being prompted.
+ */
+export function isMcpAllowChangeSet(
+  changeSet: DurablePermissionChangeSet | undefined,
+  toolName: string,
+): boolean {
+  return (
+    !!changeSet &&
+    changeSet.updates.length > 0 &&
+    changeSet.updates.every(
+      (update) =>
+        update.type === "addRules" &&
+        update.behavior === "allow" &&
+        update.rules.length > 0 &&
+        update.rules.every((rule) => rule.toolName === toolName && rule.ruleContent === undefined),
+    )
+  );
+}
+
+export function withGeneratedUpdate(name: string, rejectName = "No"): PermissionOption[] {
+  return [allowOnce(), allowWithUpdates(name), reject(rejectName)];
+}

src/permissions/options/shell.ts

@@ -0,0 +1,121 @@
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import path from "node:path";
+import type { DurablePermissionChangeSet } from "../normalization.js";
+import { plainString, type PermissionOptionContext, withOptionalUpdate } from "./shared.js";
+
+function permissionRulePrefix(value: string): string {
+  return value.endsWith(":*") ? value.slice(0, -2) : value;
+}
+
+function displayList(values: string[]): string {
+  if (values.join(", ").length > 50) return "similar";
+  if (values.length === 1) return values[0]!;
+  if (values.length === 2) return `${values[0]} and ${values[1]}`;
+  return `${values.slice(0, -1).join(", ")}, and ${values.at(-1)}`;
+}
+
+/** Shorten paths only as much as needed to distinguish them in prompt text. */
+function displayPaths(paths: string[]): string {
+  const normalizedPaths = [...new Set(paths.map((value) => path.normalize(value)))];
+  const segments = normalizedPaths.map((value) => value.split(path.sep).filter(Boolean));
+
+  // Compare equally deep suffixes so duplicate basenames gain the smallest
+  // useful parent prefix (for example, codex-acp/src/ vs claude-acp/src/).
+  const suffix = (index: number, depth: number): string =>
+    segments[index]!.slice(-depth).join(path.sep) || normalizedPaths[index]!;
+  const names = normalizedPaths.map((value, index) => {
+    const parts = segments[index]!;
+    let name = path.basename(value) || value;
+    for (let depth = 1; depth <= parts.length; depth++) {
+      const candidate = suffix(index, depth);
+      if (
+        normalizedPaths.every((_, other) => other === index || suffix(other, depth) !== candidate)
+      ) {
+        name = candidate;
+        break;
+      }
+      if (depth === parts.length) name = value;
+    }
+    return name.endsWith(path.sep) ? name : `${name}${path.sep}`;
+  });
+
+  // Native Claude labels enumerate two paths and summarize larger sets.
+  if (names.length <= 2) return displayList(names);
+  return `${names[0]}, ${names[1]} and ${names.length - 2} more`;
+}
+
+/** Plain-text port of Claude Code's generateShellSuggestionsLabel. */
+function shellSuggestionsLabel(
+  toolName: "Bash" | "PowerShell",
+  changeSet: DurablePermissionChangeSet,
+): string | undefined {
+  const representable = changeSet.updates.every((update) => {
+    if (update.type === "addDirectories") return update.destination === "session";
+    if (update.type !== "addRules" || update.behavior !== "allow") return false;
+    return update.rules.every(
+      (rule) =>
+        (rule.toolName === toolName || rule.toolName === "Read") &&
+        plainString(rule.ruleContent) !== undefined,
+    );
+  });
+  if (!representable) return undefined;
+
+  const rules = changeSet.updates
+    .filter((update) => update.type === "addRules")
+    .flatMap((update) => update.rules);
+  const readPaths = rules
+    .filter((rule) => rule.toolName === "Read")
+    .map((rule) => rule.ruleContent?.replace(/\/\*\*$/, ""))
+    .filter((value): value is string => !!value);
+  const commands = [
+    ...new Set(
+      rules
+        .filter((rule) => rule.toolName === toolName && rule.ruleContent)
+        .map((rule) => permissionRulePrefix(rule.ruleContent!)),
+    ),
+  ];
+  const directories = changeSet.updates
+    .filter((update) => update.type === "addDirectories")
+    .flatMap((update) => update.directories);
+  const hasPaths = readPaths.length > 0 || directories.length > 0;
+
+  if (readPaths.length > 0 && directories.length === 0 && commands.length === 0) {
+    return `Yes, allow reading from ${displayPaths(readPaths)} from this project`;
+  }
+  if (directories.length > 0 && readPaths.length === 0 && commands.length === 0) {
+    return `Yes, and always allow access to ${displayPaths(directories)} from this project`;
+  }
+  if (commands.length > 0 && !hasPaths) {
+    return `Yes, and don't ask again for ${displayList(commands)} commands`;
+  }
+  if (hasPaths && commands.length === 0) {
+    return `Yes, and always allow access to ${displayPaths([...directories, ...readPaths])} from this project`;
+  }
+  if (hasPaths && commands.length > 0) {
+    const paths = [...directories, ...readPaths];
+    return paths.length === 1 && commands.length === 1
+      ? `Yes, and allow access to ${displayPaths(paths)} and ${displayList(commands)} commands`
+      : `Yes, and allow ${displayPaths(paths)} access and ${displayList(commands)} commands`;
+  }
+  return undefined;
+}
+
+function buildShellPermissionOptions(
+  context: PermissionOptionContext,
+  toolName: "Bash" | "PowerShell",
+): PermissionOption[] {
+  const name = context.durableChangeSet
+    ? shellSuggestionsLabel(toolName, context.durableChangeSet)
+    : undefined;
+  return withOptionalUpdate(context.durableChangeSet, name, "Yes", "No");
+}
+
+export function buildBashPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  return buildShellPermissionOptions(context, "Bash");
+}
+
+export function buildPowerShellPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  return buildShellPermissionOptions(context, "PowerShell");
+}

src/permissions/options/tools.ts

@@ -0,0 +1,178 @@
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import {
+  allowOnce,
+  exactLocalAllowRule,
+  isMcpAllowChangeSet,
+  PERMISSION_OPTION_ID,
+  plainString,
+  type PermissionOptionContext,
+  reject,
+  withGeneratedUpdate,
+  withOptionalUpdate,
+} from "./shared.js";
+
+export function buildWebFetchPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  const url = plainString(context.input.url);
+  if (url && context.allowPersistentOptions !== false) {
+    try {
+      const hostname = new URL(url).hostname;
+      if (hostname) {
+        return withGeneratedUpdate(`Yes, and don't ask again for ${hostname}`);
+      }
+    } catch {
+      // Invalid input cannot produce Claude Code's domain-specific option.
+    }
+  }
+  return [allowOnce(), reject("No")];
+}
+
+export function buildSkillPermissionOptions(context: PermissionOptionContext): PermissionOption[] {
+  const skill = plainString(context.input.skill);
+  const options = [allowOnce()];
+  if (skill && context.allowPersistentOptions !== false) {
+    options.push({
+      optionId: PERMISSION_OPTION_ID.allowSkillExact,
+      name: `Yes, and don't ask again for ${skill}`,
+      kind: "allow_always",
+    });
+    const spaceIndex = skill.indexOf(" ");
+    if (spaceIndex > 0) {
+      const prefix = `${skill.slice(0, spaceIndex)}:*`;
+      options.push({
+        optionId: PERMISSION_OPTION_ID.allowSkillPrefix,
+        name: `Yes, and don't ask again for ${prefix} commands`,
+        kind: "allow_always",
+      });
+    }
+  }
+  options.push(reject("No"));
+  return options;
+}
+
+export function buildEnterPlanModePermissionOptions(): PermissionOption[] {
+  return [allowOnce("Yes, enter plan mode"), reject("No, start implementing now")];
+}
+
+export function buildExitPlanModePermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  const modes = new Set(context.availableModes);
+  const options: PermissionOption[] = [];
+  // Claude Code offers bypass only when the user launched with it, so it can
+  // prefer bypass outright. The adapter advertises bypass by default, so Auto
+  // leads unless the session was in bypass before entering plan mode. Both stay
+  // selectable: they have different permission semantics.
+  const elevatedModes = (
+    context.prePlanMode === "bypassPermissions"
+      ? (["bypassPermissions", "auto"] as const)
+      : (["auto", "bypassPermissions"] as const)
+  ).filter((mode) => modes.has(mode));
+  const preferredMode = elevatedModes[0] ?? "acceptEdits";
+  if (plainString(context.input.plan)) {
+    const usage =
+      context.contextUsedPercent === undefined ? "" : ` (${context.contextUsedPercent}% used)`;
+    options.push(
+      preferredMode === "auto"
+        ? {
+            optionId: PERMISSION_OPTION_ID.exitPlanClearAuto,
+            name: `Yes, clear context${usage} and use auto mode`,
+            kind: "allow_always",
+          }
+        : preferredMode === "bypassPermissions"
+          ? {
+              optionId: PERMISSION_OPTION_ID.exitPlanClearBypass,
+              name: `Yes, clear context${usage} and bypass permissions`,
+              kind: "allow_always",
+            }
+          : {
+              optionId: PERMISSION_OPTION_ID.exitPlanClearAcceptEdits,
+              name: `Yes, clear context${usage} and auto-accept edits`,
+              kind: "allow_always",
+            },
+    );
+  }
+  for (const mode of elevatedModes) {
+    options.push(
+      mode === "auto"
+        ? {
+            optionId: PERMISSION_OPTION_ID.exitPlanAuto,
+            name: "Yes, and use auto mode",
+            kind: "allow_always",
+          }
+        : {
+            optionId: PERMISSION_OPTION_ID.exitPlanBypass,
+            name: "Yes, and bypass permissions",
+            kind: "allow_always",
+          },
+    );
+  }
+  if (elevatedModes.length === 0) {
+    options.push({
+      optionId: PERMISSION_OPTION_ID.exitPlanAcceptEdits,
+      name: "Yes, auto-accept edits",
+      kind: "allow_always",
+    });
+  }
+  options.push({
+    optionId: PERMISSION_OPTION_ID.exitPlanDefault,
+    name: "Yes, manually approve edits",
+    kind: "allow_once",
+  });
+  options.push(reject("No, keep planning"));
+  return options;
+}
+
+export function buildSandboxNetworkPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  const host = plainString(context.input.host);
+  const name =
+    host && exactLocalAllowRule(context.durableChangeSet, context.toolName, host)
+      ? `Yes, and don't ask again for ${host}`
+      : undefined;
+  return withOptionalUpdate(context.durableChangeSet, name, "Yes", "No");
+}
+
+export function buildFallbackPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  const toolLabel = plainString(context.displayName) ?? context.toolName;
+  if (context.toolName.startsWith("mcp__")) {
+    const changeSet =
+      context.allowPersistentOptions !== false &&
+      isMcpAllowChangeSet(context.durableChangeSet, context.toolName)
+        ? context.durableChangeSet
+        : undefined;
+    return withOptionalUpdate(
+      changeSet,
+      changeSet ? `Yes, and don't ask again for ${toolLabel} commands` : undefined,
+    );
+  }
+  if (context.allowPersistentOptions !== false) {
+    return withGeneratedUpdate(`Yes, and don't ask again for ${toolLabel} commands`);
+  }
+  return [allowOnce(), reject("No")];
+}
+
+const COMPUTER_USE_MCP_TOOL_PREFIX = "mcp__computer-use__";
+
+export function isComputerUseMcpTool(toolName: string): boolean {
+  return toolName.startsWith(COMPUTER_USE_MCP_TOOL_PREFIX);
+}
+
+export function buildComputerUseMcpPermissionOptions(
+  context: PermissionOptionContext,
+): PermissionOption[] {
+  const toolLabel = plainString(context.displayName) ?? context.toolName;
+  const changeSet =
+    context.allowPersistentOptions !== false &&
+    isMcpAllowChangeSet(context.durableChangeSet, context.toolName)
+      ? context.durableChangeSet
+      : undefined;
+  return withOptionalUpdate(
+    changeSet,
+    changeSet ? `Yes, and don't ask again for ${toolLabel}` : undefined,
+  );
+}

src/permissions/presentation.ts

@@ -0,0 +1,120 @@
+import type { RequestPermissionRequest, ToolCallContent } from "@agentclientprotocol/sdk";
+import { AIR_PERMISSION_KEY, withAirMeta } from "../air-extension.js";
+import { ClientCapabilities } from "../tool-calls/client-capabilities.js";
+import { AcpToolCallRenderer } from "../tool-calls/renderer.js";
+
+export interface ClaudePermissionPresentationInput {
+  toolName: string;
+  input: Record<string, unknown>;
+  toolUseID: string;
+  cwd?: string;
+  capabilities?: ClientCapabilities;
+  /** The exact patch of the change to approve, for a negotiated `diffPatch` client. */
+  previewContent?: ToolCallContent[];
+  blockedPath?: string;
+  title?: string;
+  displayName?: string;
+  description?: string;
+  decisionReason?: string;
+  defaultToNo?: boolean;
+}
+
+function humanText(value: unknown, maxLength: number, singleLine = false): string | undefined {
+  if (typeof value !== "string") return undefined;
+  const withoutControls = Array.from(value)
+    .filter((character) => {
+      const code = character.charCodeAt(0);
+      return !(
+        code <= 0x08 ||
+        code === 0x0b ||
+        code === 0x0c ||
+        (code >= 0x0e && code <= 0x1f) ||
+        code === 0x7f
+      );
+    })
+    .join("");
+  const normalized = singleLine
+    ? withoutControls.replace(/\s+/gu, " ").trim()
+    : withoutControls.trim();
+  return normalized && normalized.length <= maxLength ? normalized : undefined;
+}
+
+function compactText(value: unknown): string | undefined {
+  return humanText(value, 160, true);
+}
+
+/**
+ * The permission request presentation.
+ *
+ * The request `toolCall` carries `toolCallId`, `title`, and `rawInput`. The
+ * adapter emits the `tool_call` before the request, so the client already
+ * holds the rest. The request adds only what it shows new: the exact preview
+ * patch, and the blocked path when the tool call has no such location.
+ */
+export function buildClaudePermissionPresentation(
+  value: ClaudePermissionPresentationInput,
+): Pick<RequestPermissionRequest, "toolCall" | "_meta"> {
+  const capabilities = value.capabilities ?? new ClientCapabilities();
+  const renderer = new AcpToolCallRenderer(capabilities);
+  const toolUse = { id: value.toolUseID, name: value.toolName, input: value.input };
+  const facts = renderer.facts(toolUse, value.cwd);
+  const host =
+    value.toolName === "SandboxNetworkAccess" ? compactText(value.input.host) : undefined;
+  const isComputerUse = value.toolName.startsWith("mcp__computer-use__");
+  const subjectTitle = host ?? (isComputerUse ? compactText(value.displayName) : undefined);
+  // Reuse the exact standard tool-call heading as the permission heading so
+  // the approval never maintains a second, divergent name for the operation.
+  // decisionReason is temporarily exposed as the permission description so
+  // its actual SDK values can be inspected; it remains diagnostic policy text.
+  const toolCallTitle = subjectTitle ?? facts.title;
+  const permissionTitle = value.toolName === "ExitPlanMode" ? "Ready to code?" : toolCallTitle;
+  // Shell titles are executable input: compacting whitespace changes quoted
+  // arguments and comment boundaries, and length limits can hide the command.
+  const title =
+    value.toolName === "Bash" || value.toolName === "PowerShell"
+      ? permissionTitle
+      : (humanText(permissionTitle, 4_000, true) ?? "Use tool?");
+  const decisionReason = humanText(value.decisionReason, 4_000);
+  const description = decisionReason ? `Reason: ${decisionReason}` : undefined;
+  const blockedPath = humanText(value.blockedPath, 4_096, true);
+  const extraLocations =
+    blockedPath && !(facts.locations ?? []).some((location) => location.path === blockedPath)
+      ? [{ path: blockedPath }]
+      : undefined;
+  return {
+    toolCall: renderer.permissionToolCall(toolUse, {
+      cwd: value.cwd,
+      title: toolCallTitle,
+      previewContent: value.previewContent,
+      extraLocations,
+      // The upstream request shows the input of a network or computer-use
+      // request that has no content of its own.
+      fallbackContent:
+        host || isComputerUse
+          ? [
+              {
+                type: "content" as const,
+                content: {
+                  type: "text" as const,
+                  text: `\`\`\`json\n${JSON.stringify(value.input, null, 2)}\n\`\`\``,
+                },
+              },
+            ]
+          : undefined,
+    }),
+    // Only AIR gets the permission presentation.
+    ...(title && capabilities.air.client
+      ? {
+          _meta: withAirMeta(undefined, AIR_PERMISSION_KEY, {
+            version: 1,
+            title,
+            ...(description ? { description } : {}),
+            // The CLI's own hint, forwarded so a client that can pre-select
+            // an option keeps the decline focused; the option order already
+            // leads with the reject options when this is set.
+            ...(value.defaultToNo === true ? { defaultToNo: true } : {}),
+          }),
+        }
+      : {}),
+  };
+}

src/permissions/response.ts

@@ -0,0 +1,36 @@
+import type { RequestPermissionResponse } from "@agentclientprotocol/sdk";
+import type { PermissionOption } from "@agentclientprotocol/sdk";
+import type { PermissionMode, PermissionResult } from "@anthropic-ai/claude-agent-sdk";
+import type { DurablePermissionChangeSet } from "./normalization.js";
+import { applyClaudePermissionSelection, parseClaudePermissionSelection } from "./effects.js";
+
+export interface ClaudePermissionDecision {
+  permissionResult: PermissionResult;
+  contextResetMode?: PermissionMode;
+}
+
+/** Decode, validate, and interpret an ACP response exactly once. */
+export function decodeClaudePermissionResponse(
+  response: RequestPermissionResponse,
+  toolName: string,
+  input: Record<string, unknown>,
+  toolUseID: string,
+  offeredOptions: readonly PermissionOption[],
+  durableChangeSet?: DurablePermissionChangeSet,
+): ClaudePermissionDecision {
+  const selection = parseClaudePermissionSelection(response, toolName);
+  const offeredOption = offeredOptions.find((option) => option.optionId === selection.optionId);
+  if (!offeredOption) {
+    throw new Error(`Permission option was not offered: ${selection.optionId}`);
+  }
+  const permissionResult = applyClaudePermissionSelection(selection, {
+    toolName,
+    input,
+    toolUseID,
+    durableChangeSet,
+  });
+  return {
+    permissionResult,
+    ...(selection.contextResetMode ? { contextResetMode: selection.contextResetMode } : {}),
+  };
+}

src/resumed-session.ts

@@ -0,0 +1,158 @@
+import { getSessionMessages, type SessionMessage } from "@anthropic-ai/claude-agent-sdk";
+import { access, open, readdir } from "node:fs/promises";
+import path from "node:path";
+import { claudeConfigDir } from "./paths.js";
+import { SessionTiming } from "./session-timing.js";
+
+/** The size of one backward read of a transcript. */
+const TAIL_CHUNK_BYTES = 64 * 1024;
+
+type ResumeLogger = {
+  log: (...args: unknown[]) => void;
+  error: (...args: unknown[]) => void;
+};
+
+export type ResumedSessionSnapshot = {
+  messages?: SessionMessage[];
+  model?: string;
+};
+
+/** Return the concrete model recorded by the last real assistant response.
+ * Claude Code restores a resumed query from this same transcript field.
+ * Synthetic assistant records use angle-bracket placeholders and do not
+ * describe a model the resumed query can run. */
+export function resumedModelFromTranscript(messages: SessionMessage[]): string | undefined {
+  for (let index = messages.length - 1; index >= 0; index--) {
+    const entry = messages[index];
+    if (
+      entry?.type !== "assistant" ||
+      entry.parent_tool_use_id != null ||
+      entry.parent_agent_id != null ||
+      !entry.message ||
+      typeof entry.message !== "object"
+    ) {
+      continue;
+    }
+    const model = concreteModel((entry.message as { model?: unknown }).model);
+    if (model) return model;
+  }
+  return undefined;
+}
+
+/** The model name, or undefined for a missing or a synthetic `<…>` model. */
+function concreteModel(model: unknown): string | undefined {
+  if (typeof model !== "string") return undefined;
+  const name = model.trim();
+  return name.length > 0 && !/^<[^>]+>$/.test(name) ? name : undefined;
+}
+
+/** Read the resume model from the local transcript without starting a Claude
+ * control request. This is intentionally on the load critical path. */
+export async function readResumedSession(
+  sessionId: string,
+  logger?: ResumeLogger,
+): Promise<ResumedSessionSnapshot> {
+  const timing = new SessionTiming(logger, "models", sessionId);
+  try {
+    // Deliberately search all project directories, matching replaySessionHistory.
+    // A client may reopen a session from a worktree or normalized path that is
+    // different from the directory under which Claude persisted the transcript.
+    const messages = await getSessionMessages(sessionId);
+    const model = resumedModelFromTranscript(messages);
+    timing.phase("read-transcript", ` messages=${messages.length} model=${model ?? "unknown"}`);
+    return { messages, model };
+  } catch (error) {
+    timing.phase("read-transcript", " outcome=error");
+    logger?.error(`Failed to read transcript for resumed session ${sessionId}:`, error);
+    return {};
+  }
+}
+
+/**
+ * Read the resume model of a session from the end of its local transcript.
+ *
+ * A resume needs only the model, not the messages. The transcript file is
+ * read backwards until the last real assistant record of the main thread, so
+ * the cost does not grow with the length of the session. A session without a
+ * local transcript file falls back to {@link readResumedSession}.
+ */
+export async function readResumedModel(
+  sessionId: string,
+  logger?: ResumeLogger,
+): Promise<string | undefined> {
+  const timing = new SessionTiming(logger, "models", sessionId);
+  try {
+    const filePath = await findTranscript(sessionId);
+    if (filePath) {
+      const model = await lastAssistantModel(filePath);
+      timing.phase("read-transcript-tail", ` model=${model ?? "unknown"}`);
+      return model;
+    }
+  } catch (error) {
+    timing.phase("read-transcript-tail", " outcome=error");
+    logger?.error(`Failed to read the transcript tail of resumed session ${sessionId}:`, error);
+  }
+  return (await readResumedSession(sessionId, logger)).model;
+}
+
+/** The local transcript of a session in any project directory, as the SDK looks it up. */
+export async function findTranscript(sessionId: string): Promise<string | undefined> {
+  const projects = path.join(claudeConfigDir(), "projects");
+  let directories: string[];
+  try {
+    directories = await readdir(projects);
+  } catch {
+    return undefined;
+  }
+  for (const directory of directories) {
+    const candidate = path.join(projects, directory, `${sessionId}.jsonl`);
+    try {
+      await access(candidate);
+      return candidate;
+    } catch {
+      // Not in this project directory.
+    }
+  }
+  return undefined;
+}
+
+/** The model of the last real assistant record of the main thread in a JSONL transcript. */
+async function lastAssistantModel(filePath: string): Promise<string | undefined> {
+  const handle = await open(filePath, "r");
+  try {
+    let end = (await handle.stat()).size;
+    // The bytes of the line whose start is not read yet, in file order.
+    let pending: Buffer[] = [];
+    while (end > 0) {
+      const start = Math.max(0, end - TAIL_CHUNK_BYTES);
+      let chunk = Buffer.alloc(end - start);
+      await handle.read(chunk, 0, chunk.length, start);
+      for (let at = chunk.lastIndexOf(0x0a); at >= 0; at = chunk.lastIndexOf(0x0a)) {
+        const model = assistantModelOfLine(Buffer.concat([chunk.subarray(at + 1), ...pending]));
+        if (model) return model;
+        pending = [];
+        chunk = chunk.subarray(0, at);
+      }
+      pending.unshift(chunk);
+      end = start;
+    }
+    return assistantModelOfLine(Buffer.concat(pending));
+  } finally {
+    await handle.close();
+  }
+}
+
+function assistantModelOfLine(line: Buffer): string | undefined {
+  // Most lines are not assistant records. The check skips their JSON parse.
+  if (line.indexOf('"assistant"') < 0) return undefined;
+  let entry: unknown;
+  try {
+    entry = JSON.parse(line.toString("utf8"));
+  } catch {
+    return undefined;
+  }
+  if (!entry || typeof entry !== "object") return undefined;
+  const record = entry as { type?: unknown; isSidechain?: unknown; message?: { model?: unknown } };
+  if (record.type !== "assistant" || record.isSidechain === true) return undefined;
+  return concreteModel(record.message?.model);
+}

src/session-config-ids.ts

@@ -0,0 +1,3 @@
+/** Shared sentinels and ids for session preferences managed by the adapter. */
+export const DEFAULT_MODEL_ID = "default";
+export const EFFORT_CONFIG_ID = "effort";

src/session-effort.ts

@@ -0,0 +1,118 @@
+import type { SessionConfigOption } from "@agentclientprotocol/sdk";
+import type { EffortLevel, ModelInfo, Settings } from "@anthropic-ai/claude-agent-sdk";
+import { AIR_RECOMMENDED_CONFIG_VALUE_CAPABILITY, withAirMeta } from "./air-extension.js";
+import { EFFORT_CONFIG_ID } from "./session-config-ids.js";
+
+export { EFFORT_CONFIG_ID } from "./session-config-ids.js";
+
+// The SDK drops `undefined` during JSON transport and only clears a flag-layer
+// setting when it receives an explicit `null`. Map both an absent picker and
+// the legacy "default" row to null so a previously applied effort is cleared.
+export function toSdkEffortLevel(value: string | undefined): EffortLevel | null {
+  return value === undefined || value === "default" ? null : (value as EffortLevel);
+}
+
+function canonicalizeModelSettingsKey(value: string): string {
+  return value
+    .trim()
+    .toLowerCase()
+    .replace(/-(\d+m)$/i, "[$1]");
+}
+
+/** Resolve the effort the CLI will use: per-model settings first, then the
+ *  legacy top-level effort setting. Model settings are keyed by canonical
+ *  model name, so try the resolved SDK model before picker and raw IDs. */
+export function settingsEffortForModel(
+  settings: Settings,
+  modelInfo: ModelInfo | undefined,
+  modelId?: string,
+): string | undefined {
+  const modelSettings = settings.modelSettings;
+  if (modelSettings) {
+    for (const key of [modelInfo?.resolvedModel, modelInfo?.value, modelId]) {
+      if (key === undefined) continue;
+      const exact = modelSettings[key]?.effortLevel;
+      if (typeof exact === "string") return exact;
+      const canonicalKey = canonicalizeModelSettingsKey(key);
+      const matchingEntry = Object.entries(modelSettings).find(
+        ([candidate]) => canonicalizeModelSettingsKey(candidate) === canonicalKey,
+      );
+      const perModel = matchingEntry?.[1]?.effortLevel;
+      if (typeof perModel === "string") return perModel;
+    }
+  }
+  return settings.effortLevel;
+}
+
+/** Programmatic query settings have higher priority than file-backed settings,
+ * matching the SDK. Keep unrelated per-model entries from lower tiers while
+ * replacing entries supplied at the programmatic tier. */
+export function mergeEffortSettings(base: Settings, override: Settings | undefined): Settings {
+  if (!override) return base;
+  const overriddenModelKeys = new Set(
+    Object.keys(override.modelSettings ?? {}).map(canonicalizeModelSettingsKey),
+  );
+  const unshadowedBaseModelSettings = Object.fromEntries(
+    Object.entries(base.modelSettings ?? {}).filter(
+      ([key]) => !overriddenModelKeys.has(canonicalizeModelSettingsKey(key)),
+    ),
+  );
+  return {
+    ...base,
+    ...override,
+    modelSettings:
+      base.modelSettings || override.modelSettings
+        ? { ...unshadowedBaseModelSettings, ...override.modelSettings }
+        : undefined,
+  };
+}
+
+export function buildEffortConfigOption(
+  modelInfos: ModelInfo[],
+  currentModelId: string,
+  currentEffortLevel: string | undefined,
+  useRecommendedValue: boolean,
+): SessionConfigOption | undefined {
+  const currentModelInfo = modelInfos.find((model) => model.value === currentModelId);
+  const supportedLevels = currentModelInfo?.supportsEffort
+    ? (currentModelInfo.supportedEffortLevels ?? [])
+    : [];
+  if (supportedLevels.length === 0) return undefined;
+
+  const recommendedEffort = (supportedLevels as string[]).includes("medium")
+    ? "medium"
+    : supportedLevels[0];
+  const options = [
+    ...(useRecommendedValue ? [] : [{ value: "default", name: "Default" }]),
+    ...supportedLevels.map((level) => ({
+      value: level,
+      name: level
+        .split(/[_-]/)
+        .map((part) => (part ? part.charAt(0).toUpperCase() + part.slice(1) : part))
+        .join(" "),
+    })),
+  ];
+  const includes = (level: string) =>
+    (!useRecommendedValue && level === "default") || (supportedLevels as string[]).includes(level);
+  const currentValue =
+    currentEffortLevel && includes(currentEffortLevel)
+      ? currentEffortLevel
+      : useRecommendedValue
+        ? recommendedEffort
+        : "default";
+
+  return {
+    id: EFFORT_CONFIG_ID,
+    name: "Effort",
+    description: "Available effort levels for this model",
+    category: "thought_level",
+    type: "select",
+    currentValue,
+    options,
+    ...(useRecommendedValue
+      ? {
+          _meta: withAirMeta(undefined, AIR_RECOMMENDED_CONFIG_VALUE_CAPABILITY, recommendedEffort),
+        }
+      : {}),
+  };
+}

src/session-failure-extension.ts

@@ -0,0 +1,486 @@
+import type { ClientCapabilities, SessionNotification } from "@agentclientprotocol/sdk";
+import {
+  getSessionMessages,
+  type SDKAssistantMessageError,
+  USAGE_LIMIT_ERROR_PREFIXES,
+} from "@anthropic-ai/claude-agent-sdk";
+import { randomUUID } from "node:crypto";
+import {
+  AIR_SESSION_FAILURE_CAPABILITY,
+  airCapabilityMeta,
+  clientSupportsAirCapability,
+  withAirMeta,
+} from "./air-extension.js";
+
+export function airSessionFailureCapabilityMeta(...additionalCapabilities: string[]) {
+  return airCapabilityMeta(AIR_SESSION_FAILURE_CAPABILITY, ...additionalCapabilities);
+}
+
+export type ClaudeFailureKind =
+  | "access_denied"
+  | "advisory"
+  | "auth_required"
+  | "bad_request"
+  | "budget_exhausted"
+  | "context_exhausted"
+  | "internal_error"
+  | "overloaded"
+  | "provider_error"
+  | "quota_exhausted"
+  | "rate_limited"
+  | "transport_lost"
+  | "worker_shutdown";
+
+type AirSessionFailureCategory =
+  "connection" | "access" | "limit" | "request" | "service" | "unknown";
+
+type AirSessionFailureSeverity = "warning" | "error";
+type AirSessionFailureAction = "retry" | "login" | "new_session";
+
+type SessionFailureRecoveryPolicy =
+  "never" | "next_attempt" | "real_model_success" | "auth_status" | "runtime_rebind";
+
+export type PublishedSessionFailure = {
+  id: string;
+  revision: number;
+  kind: ClaudeFailureKind;
+  category: AirSessionFailureCategory;
+  turnId?: string;
+  severity: AirSessionFailureSeverity;
+  title: string;
+  details?: string;
+  /** A machine-readable refinement of `kind`, e.g. the `--hide-claude-auth`
+   *  subscription guard's reason on an `auth_required` failure. Absent for a
+   *  plain sign-out. */
+  reason?: string;
+  actions: AirSessionFailureAction[];
+  recoveryPolicy: SessionFailureRecoveryPolicy;
+};
+
+type SessionFailureOptions = {
+  turnId?: string;
+  sessionScoped?: boolean;
+  title?: string;
+  details?: string;
+  severity?: AirSessionFailureSeverity;
+  reason?: string;
+};
+
+export type SessionFailureState = {
+  epoch: string;
+  revisions: Map<string, number>;
+  active: Map<string, PublishedSessionFailure>;
+  nextIncident?: number;
+  lastNotice?: { title: string; id: string };
+};
+
+type Logger = {
+  error: (...args: unknown[]) => void;
+};
+
+export function createSessionFailureState(): SessionFailureState {
+  return {
+    epoch: randomUUID(),
+    revisions: new Map(),
+    active: new Map(),
+  };
+}
+
+const AIR_FAILURE_POLICY: Record<
+  ClaudeFailureKind,
+  {
+    category: AirSessionFailureCategory;
+    actions: AirSessionFailureAction[];
+    fallbackTitle: string;
+  }
+> = {
+  // Account or credential blocks that signing in again cannot fix: the
+  // organization must complete verification, or the cloud provider's
+  // credentials must be refreshed outside Claude. No `login` action, and not
+  // sticky like `auth_required` (nothing clears at `auth_status`).
+  access_denied: {
+    category: "service",
+    actions: ["retry"],
+    fallbackTitle: "Claude could not access the account or provider credentials.",
+  },
+  advisory: {
+    category: "unknown",
+    actions: [],
+    fallbackTitle: "Claude reported a notice.",
+  },
+  auth_required: {
+    category: "access",
+    actions: ["login"],
+    fallbackTitle: "Sign in to continue using Claude.",
+  },
+  bad_request: {
+    category: "request",
+    actions: [],
+    fallbackTitle: "Claude could not process this request.",
+  },
+  budget_exhausted: {
+    category: "limit",
+    actions: ["new_session"],
+    fallbackTitle: "This Claude session reached its configured budget.",
+  },
+  context_exhausted: {
+    category: "limit",
+    actions: ["new_session"],
+    fallbackTitle: "This Claude turn reached its configured limit.",
+  },
+  internal_error: {
+    category: "service",
+    actions: ["retry", "new_session"],
+    fallbackTitle: "Claude Agent encountered an internal error.",
+  },
+  overloaded: {
+    category: "service",
+    actions: ["retry"],
+    fallbackTitle: "Claude is temporarily overloaded.",
+  },
+  provider_error: {
+    category: "service",
+    actions: ["retry"],
+    fallbackTitle: "The model provider reported an error.",
+  },
+  quota_exhausted: {
+    category: "limit",
+    actions: [],
+    fallbackTitle: "The Claude account has no available quota.",
+  },
+  rate_limited: {
+    category: "limit",
+    actions: ["retry"],
+    fallbackTitle: "Claude is temporarily rate limited.",
+  },
+  transport_lost: {
+    category: "connection",
+    actions: ["new_session"],
+    fallbackTitle: "The connection to Claude was lost.",
+  },
+  worker_shutdown: {
+    category: "connection",
+    actions: ["new_session"],
+    fallbackTitle: "The Claude worker is shutting down.",
+  },
+};
+
+export function sessionFailureMeta(failure: PublishedSessionFailure) {
+  return withAirMeta(undefined, AIR_SESSION_FAILURE_CAPABILITY, {
+    id: failure.id,
+    revision: failure.revision,
+    category: failure.category,
+    severity: failure.severity,
+    title: failure.title,
+    ...(failure.details ? { details: failure.details } : {}),
+    ...(failure.reason ? { reason: failure.reason } : {}),
+    actions: failure.actions,
+  });
+}
+
+/** `getSessionMessages` deliberately exposes only the API message and strips
+ *  transcript-level `error` / `isApiErrorMessage` fields. The SDK exports the
+ *  exact stable prefixes used by its synthetic usage-limit errors, so replay
+ *  can recover this one typed failure without matching arbitrary model prose. */
+export function assistantMessageText(apiMessage: unknown): string | undefined {
+  if (!apiMessage || typeof apiMessage !== "object") return undefined;
+  const { content } = apiMessage as { content?: unknown };
+  if (typeof content === "string") return content || undefined;
+  if (!Array.isArray(content)) return undefined;
+  const text = content
+    .map((block) =>
+      block &&
+      typeof block === "object" &&
+      "type" in block &&
+      block.type === "text" &&
+      "text" in block &&
+      typeof block.text === "string"
+        ? block.text
+        : "",
+    )
+    .join("");
+  return text || undefined;
+}
+
+export function isSyntheticUsageLimitMessage(apiMessage: unknown): boolean {
+  if (!apiMessage || typeof apiMessage !== "object") return false;
+  const { model } = apiMessage as { model?: unknown };
+  if (model !== "<synthetic>") return false;
+  const text = assistantMessageText(apiMessage);
+  if (!text) return false;
+  return USAGE_LIMIT_ERROR_PREFIXES.some((prefix) => text.startsWith(prefix));
+}
+
+export function activeUsageLimitMessage(
+  messages: Awaited<ReturnType<typeof getSessionMessages>>,
+): { uuid: string; title: string } | undefined {
+  let active: { uuid: string; title: string } | undefined;
+  for (const message of messages) {
+    if (message.type !== "assistant" || message.parent_tool_use_id !== null) continue;
+    if (isSyntheticUsageLimitMessage(message.message)) {
+      const title = assistantMessageText(message.message);
+      if (title) active = { uuid: message.uuid, title };
+      continue;
+    }
+    const model =
+      message.message && typeof message.message === "object" && "model" in message.message
+        ? message.message.model
+        : undefined;
+    // A later real model answer proves the account recovered. Synthetic
+    // local-command/interruption messages do not: they can be appended while
+    // the provider remains unavailable.
+    if (model !== undefined && model !== "<synthetic>") active = undefined;
+  }
+  return active;
+}
+
+export function supportsAirSessionFailures(capabilities?: ClientCapabilities): boolean {
+  return clientSupportsAirCapability(capabilities, AIR_SESSION_FAILURE_CAPABILITY);
+}
+
+function sessionFailureRecoveryPolicy(
+  kind: ClaudeFailureKind,
+  turnId?: string,
+): SessionFailureRecoveryPolicy {
+  switch (kind) {
+    case "advisory":
+      return "never";
+    case "auth_required":
+      return "auth_status";
+    case "transport_lost":
+    case "worker_shutdown":
+      return "runtime_rebind";
+    case "quota_exhausted":
+      return "real_model_success";
+    default:
+      return turnId ? "next_attempt" : "real_model_success";
+  }
+}
+
+/** Owns the AIR failure lifecycle for both the live consumer and history replay.
+ *  Published revisions become active only after delivery succeeds; recovery only
+ *  removes internal active state because transcript records are historical. */
+export class SessionFailureController {
+  private readonly sessionId: string;
+  private readonly state: SessionFailureState;
+  private readonly capabilities?: ClientCapabilities;
+  private readonly isCurrent: () => boolean;
+  private readonly sendUpdate: (notification: SessionNotification) => Promise<void>;
+  private readonly logger: Logger;
+
+  constructor(options: {
+    sessionId: string;
+    state: SessionFailureState;
+    capabilities?: ClientCapabilities;
+    isCurrent: () => boolean;
+    sendUpdate: (notification: SessionNotification) => Promise<void>;
+    logger: Logger;
+  }) {
+    this.sessionId = options.sessionId;
+    this.state = options.state;
+    this.capabilities = options.capabilities;
+    this.isCurrent = options.isCurrent;
+    this.sendUpdate = options.sendUpdate;
+    this.logger = options.logger;
+  }
+
+  private isSupported(): boolean {
+    return supportsAirSessionFailures(this.capabilities);
+  }
+
+  private async emit(failure: PublishedSessionFailure): Promise<boolean> {
+    if (!this.isCurrent()) {
+      this.logger.error(
+        `Session ${this.sessionId}: ignored AIR session failure from a stale consumer`,
+      );
+      return false;
+    }
+    try {
+      await this.sendUpdate({
+        sessionId: this.sessionId,
+        update: {
+          sessionUpdate: "session_info_update",
+          _meta: sessionFailureMeta(failure),
+        },
+      });
+      return true;
+    } catch (error) {
+      this.logger.error(
+        `Session ${this.sessionId}: failed to publish AIR session failure: ${error}`,
+      );
+      return false;
+    }
+  }
+
+  /** Whether a session-scoped error of `kind` is active. A turn-scoped
+   *  warning of the same kind (an `api_retry` notice) does not count: it
+   *  reports a retry in progress, not the state the error would publish.
+   *
+   *  `reason` refines `kind`, so the active record must carry the same one,
+   *  and an omitted `reason` matches only a record with no reason. A plain
+   *  sign-out and the `--hide-claude-auth` subscription refusal are both
+   *  `auth_required`, but they tell the user different things. Neither may
+   *  suppress the other. */
+  hasActiveSessionError(kind: ClaudeFailureKind, reason?: string): boolean {
+    for (const failure of this.state.active.values()) {
+      if (
+        failure.kind === kind &&
+        failure.severity === "error" &&
+        failure.turnId === undefined &&
+        failure.reason === reason
+      ) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  recordActive(failure: PublishedSessionFailure): void {
+    this.state.revisions.set(failure.id, failure.revision);
+    this.state.active.set(failure.id, failure);
+    this.state.lastNotice =
+      failure.kind === "advisory" ? { title: failure.title, id: failure.id } : undefined;
+  }
+
+  async clear(
+    shouldClear: (failure: PublishedSessionFailure) => boolean = () => true,
+  ): Promise<boolean> {
+    if (!this.isSupported()) return true;
+    this.state.lastNotice = undefined;
+    for (const failure of [...this.state.active.values()]) {
+      if (!shouldClear(failure)) continue;
+      this.state.active.delete(failure.id);
+    }
+    return true;
+  }
+
+  async prepare(
+    kind: ClaudeFailureKind,
+    failureOptions: SessionFailureOptions = {},
+  ): Promise<PublishedSessionFailure | undefined> {
+    if (!this.isSupported() || !this.isCurrent()) return undefined;
+    const policy = AIR_FAILURE_POLICY[kind];
+    const title = failureOptions.title || policy.fallbackTitle;
+    if (kind === "advisory") {
+      const id =
+        this.state.lastNotice?.title === title
+          ? this.state.lastNotice.id
+          : `${this.sessionId}:notice:${this.state.epoch}:${this.state.nextIncident ?? 1}`;
+      if (this.state.lastNotice?.title !== title) {
+        this.state.nextIncident = (this.state.nextIncident ?? 1) + 1;
+      }
+      return {
+        id,
+        revision: (this.state.revisions.get(id) ?? 0) + 1,
+        kind,
+        category: policy.category,
+        severity: "warning",
+        title,
+        ...(failureOptions.details ? { details: failureOptions.details } : {}),
+        actions: policy.actions,
+        recoveryPolicy: sessionFailureRecoveryPolicy(kind),
+      };
+    }
+    const id =
+      failureOptions.turnId && !failureOptions.sessionScoped
+        ? `${failureOptions.turnId}:error`
+        : `${this.sessionId}:session-error:${this.state.epoch}:${this.state.nextIncident ?? 1}`;
+    if (!failureOptions.turnId || failureOptions.sessionScoped) {
+      this.state.nextIncident = (this.state.nextIncident ?? 1) + 1;
+    }
+    return {
+      id,
+      revision: (this.state.revisions.get(id) ?? 0) + 1,
+      kind,
+      category: policy.category,
+      severity: failureOptions.severity ?? "error",
+      title,
+      ...(failureOptions.details ? { details: failureOptions.details } : {}),
+      ...(failureOptions.reason ? { reason: failureOptions.reason } : {}),
+      actions: failureOptions.severity === "warning" ? [] : policy.actions,
+      recoveryPolicy: sessionFailureRecoveryPolicy(
+        kind,
+        failureOptions.turnId && !failureOptions.sessionScoped ? failureOptions.turnId : undefined,
+      ),
+      ...(failureOptions.turnId && !failureOptions.sessionScoped
+        ? { turnId: failureOptions.turnId }
+        : {}),
+    };
+  }
+
+  async publish(
+    kind: ClaudeFailureKind,
+    failureOptions: SessionFailureOptions = {},
+  ): Promise<void> {
+    const failure = await this.prepare(kind, failureOptions);
+    if (!failure) return;
+    if (await this.emit(failure)) this.recordActive(failure);
+  }
+
+  async restore(
+    id: string,
+    kind: ClaudeFailureKind,
+    title: string,
+    active = true,
+  ): Promise<boolean> {
+    if (!this.isSupported() || !this.isCurrent()) return false;
+    const policy = AIR_FAILURE_POLICY[kind];
+    const failure: PublishedSessionFailure = {
+      id,
+      revision: (this.state.revisions.get(id) ?? 0) + 1,
+      kind,
+      category: policy.category,
+      severity: "error",
+      title,
+      actions: policy.actions,
+      recoveryPolicy: sessionFailureRecoveryPolicy(kind),
+    };
+    if (!(await this.emit(failure))) return false;
+    this.state.revisions.set(failure.id, failure.revision);
+    if (active) {
+      this.state.active.set(failure.id, failure);
+    } else {
+      this.state.active.delete(failure.id);
+    }
+    return true;
+  }
+}
+
+export function providerFailureCategory(
+  errorKind?: SDKAssistantMessageError,
+  isUsageLimit = false,
+): ClaudeFailureKind {
+  if (isUsageLimit) return "quota_exhausted";
+  switch (errorKind) {
+    case "authentication_failed":
+    case "oauth_org_not_allowed":
+      return "auth_required";
+    case "billing_error":
+    case "account_on_hold":
+      return "quota_exhausted";
+    // 403 `permission_error` with error_code `verification_required` (the
+    // organization must verify at the console), and a Bedrock/Vertex/Foundry
+    // credential the CLI could not load (transient: it retries, and asks the
+    // user to check or refresh the credentials). Both are access failures
+    // `/login` does not repair, so they get their own lane rather than
+    // `auth_required`'s login action and sticky auth_status recovery.
+    case "verification_required":
+    case "cloud_credential_error":
+      return "access_denied";
+    case "rate_limit":
+      return "rate_limited";
+    case "overloaded":
+      return "overloaded";
+    case "invalid_request":
+    case "model_not_found":
+      return "bad_request";
+    case "max_output_tokens":
+      return "context_exhausted";
+    case "server_error":
+    case "unknown":
+    case undefined:
+      return "provider_error";
+    default:
+      return "provider_error";
+  }
+}

src/session-mode.ts

@@ -0,0 +1,373 @@
+import {
+  RequestError,
+  type SessionConfigOption,
+  type SessionModeState,
+  type SessionNotification,
+  type SetSessionModeRequest,
+  type SetSessionModeResponse,
+} from "@agentclientprotocol/sdk";
+import type {
+  ModelInfo,
+  PermissionMode,
+  PermissionResult,
+  Query,
+} from "@anthropic-ai/claude-agent-sdk";
+import { AIR_KIND_KEY, airOnlyMeta } from "./air-extension.js";
+import {
+  noticeOrTranscriptUpdate,
+  noticeTranscriptText,
+  sentenceCase,
+  type SessionNotice,
+} from "./session-notices.js";
+
+export const MODE_CONFIG_ID = "mode";
+export const AUTO_MODE_FALLBACK: PermissionMode = "acceptEdits";
+
+/** Reads on after the bold label in the transcript line; capitalized when it
+ *  stands alone as a notice description. */
+const AUTO_MODE_FALLBACK_REASON =
+  "the selected model does not support Auto mode; using Accept edits instead.";
+const AUTO_MODE_FALLBACK_NOTICE: SessionNotice = {
+  severity: "warning",
+  title: "Auto mode unavailable",
+  description: sentenceCase(AUTO_MODE_FALLBACK_REASON),
+};
+
+export type SessionMode = {
+  query: Pick<Query, "setPermissionMode">;
+  queryClosed?: boolean;
+  modes: SessionModeState;
+  models: { currentModelId: string };
+  modelInfos: ModelInfo[];
+  /** Prevents the model-specific Auto fallback from spamming the transcript. */
+  autoModeFallbackWarningShown?: boolean;
+  /** Initial mode fallback is reported after session/new, on the first prompt. */
+  autoModeFallbackWarningPending?: boolean;
+  /** The mode the session left when it entered plan mode, if it is in plan. */
+  prePlanMode?: string;
+};
+
+export type SessionModeManagerOptions<S extends SessionMode> = {
+  getSession(sessionId: string): S | undefined;
+  sessionEndedMessage: string;
+  updateConfigOption(sessionId: string, configId: string, value: string): Promise<void>;
+  sessionUpdate(params: SessionNotification): Promise<void>;
+  /** Whether the client can present `notice` updates; the fallback warning
+   *  is a transcript line otherwise. Read per call: capabilities are only
+   *  known after `initialize`. */
+  supportsNotices?(): boolean;
+  logError(...args: unknown[]): void;
+  /** Whether the client is AIR. Only AIR gets the mode kind, under `_meta.jetbrains.air`. */
+  airClient?(): boolean;
+};
+
+type ModeConfigSession = SessionMode & {
+  configOptions: SessionConfigOption[];
+};
+
+type InitializeSessionModeParams = {
+  query: Pick<Query, "setPermissionMode">;
+  requestedMode: PermissionMode;
+  currentModelInfo?: ModelInfo;
+  currentModelId: string;
+  /** When false, bypassPermissions is omitted from the mode catalog. */
+  allowBypass: boolean;
+};
+
+/** Owns session-mode policy and the ACP/SDK synchronization it requires. */
+export class SessionModeManager<S extends SessionMode> {
+  constructor(private readonly options: SessionModeManagerOptions<S>) {}
+
+  async initialize({
+    query,
+    requestedMode,
+    currentModelInfo,
+    currentModelId,
+    allowBypass,
+  }: InitializeSessionModeParams): Promise<{
+    modes: SessionModeState;
+    autoModeFallbackWarningPending: boolean;
+  }> {
+    const availableModes = this.buildAvailableModes(allowBypass);
+    let effectiveMode = requestedMode;
+    let autoModeFallbackWarningPending = false;
+
+    if (
+      effectiveMode === "auto" &&
+      currentModelInfo !== undefined &&
+      currentModelInfo.supportsAutoMode !== true
+    ) {
+      this.options.logError(
+        `permissions.defaultMode "auto" is not available for model ` +
+          `"${currentModelId}"; falling back to "${AUTO_MODE_FALLBACK}".`,
+      );
+      effectiveMode = AUTO_MODE_FALLBACK;
+      autoModeFallbackWarningPending = true;
+      await this.trySyncMode(query, effectiveMode, "Failed to sync clamped permissionMode to SDK:");
+    } else if (!this.isAvailable(availableModes, effectiveMode)) {
+      this.options.logError(
+        `permissions.defaultMode "${effectiveMode}" is not available in ` +
+          `this session; falling back to "default".`,
+      );
+      effectiveMode = "default";
+      await this.trySyncMode(query, effectiveMode, "Failed to sync clamped permissionMode to SDK:");
+    }
+
+    return {
+      modes: { currentModeId: effectiveMode, availableModes },
+      autoModeFallbackWarningPending,
+    };
+  }
+
+  static configOption(modes: SessionModeState): SessionConfigOption {
+    return {
+      id: MODE_CONFIG_ID,
+      name: "Mode",
+      description: "Session permission mode",
+      category: "mode",
+      type: "select",
+      currentValue: modes.currentModeId,
+      options: modes.availableModes.map((mode) => ({
+        value: mode.id,
+        name: mode.name,
+        description: mode.description,
+        _meta: mode._meta,
+      })),
+    };
+  }
+
+  syncConfig(session: ModeConfigSession, mode: string): void {
+    const previousMode = session.modes.currentModeId;
+    if (mode !== "plan") {
+      session.prePlanMode = undefined;
+    } else if (previousMode !== "plan") {
+      session.prePlanMode = previousMode;
+    }
+    session.modes = { ...session.modes, currentModeId: mode };
+    session.configOptions = session.configOptions.map((option) =>
+      option.id === MODE_CONFIG_ID && typeof option.currentValue === "string"
+        ? { ...option, currentValue: mode }
+        : option,
+    );
+  }
+
+  availableModeIds(modes: SessionModeState): string[] {
+    return modes.availableModes.map((mode) => mode.id);
+  }
+
+  effectiveMode(session: SessionMode, requestedMode: PermissionMode): PermissionMode {
+    return requestedMode === "auto" && this.isAutoUnavailable(session)
+      ? AUTO_MODE_FALLBACK
+      : requestedMode;
+  }
+
+  applyPermissionFallback(
+    session: SessionMode,
+    permissionResult: PermissionResult,
+  ): { permissionResult: PermissionResult; fallbackApplied: boolean } {
+    const fallbackApplied =
+      this.isAutoUnavailable(session) &&
+      permissionResult.behavior === "allow" &&
+      permissionResult.updatedPermissions?.some(
+        (update) => update.type === "setMode" && update.mode === "auto",
+      ) === true;
+    if (!fallbackApplied || permissionResult.behavior !== "allow") {
+      return { permissionResult, fallbackApplied: false };
+    }
+
+    return {
+      permissionResult: {
+        ...permissionResult,
+        updatedPermissions: permissionResult.updatedPermissions?.map((update) =>
+          update.type === "setMode" && update.mode === "auto"
+            ? { ...update, mode: AUTO_MODE_FALLBACK }
+            : update,
+        ),
+      },
+      fallbackApplied: true,
+    };
+  }
+
+  /** Reconcile mode after a model switch. The caller rebuilds config options
+   * before publishing the returned state change. */
+  async reconcileForModel(session: SessionMode, model: ModelInfo | undefined) {
+    if (
+      session.modes.currentModeId !== "auto" ||
+      model === undefined ||
+      model.supportsAutoMode === true
+    ) {
+      return false;
+    }
+
+    session.modes = {
+      availableModes: session.modes.availableModes,
+      currentModeId: AUTO_MODE_FALLBACK,
+    };
+    await this.trySyncMode(
+      session.query,
+      AUTO_MODE_FALLBACK,
+      `Failed to sync permissionMode to "${AUTO_MODE_FALLBACK}" after model switch invalidated "auto":`,
+    );
+    return true;
+  }
+
+  async selectMode(sessionId: string, modeId: string): Promise<PermissionMode> {
+    const session = this.requireOpenSession(sessionId);
+    const requestedMode = this.parseMode(modeId);
+    if (!this.isAvailable(session.modes.availableModes, requestedMode)) {
+      throw new Error(`Mode ${modeId} is not available in this session`);
+    }
+
+    const effectiveMode = this.effectiveMode(session, requestedMode);
+    try {
+      await session.query.setPermissionMode(effectiveMode);
+    } catch (error) {
+      if (error instanceof Error) {
+        if (!error.message) error.message = "Invalid Mode";
+        throw error;
+      }
+      // eslint-disable-next-line preserve-caught-error
+      throw new Error("Invalid Mode");
+    }
+
+    if (effectiveMode !== requestedMode) {
+      await this.publishFallbackWarning(sessionId, session);
+    }
+    return effectiveMode;
+  }
+
+  async setSessionMode(params: SetSessionModeRequest): Promise<SetSessionModeResponse> {
+    const effectiveMode = await this.selectMode(params.sessionId, params.modeId);
+    if (effectiveMode !== params.modeId) {
+      await this.publishCurrent(params.sessionId, effectiveMode);
+    }
+    await this.options.updateConfigOption(params.sessionId, MODE_CONFIG_ID, effectiveMode);
+    return {};
+  }
+
+  async publishCurrent(sessionId: string, mode: string): Promise<void> {
+    await this.options.sessionUpdate({
+      sessionId,
+      update: { sessionUpdate: "current_mode_update", currentModeId: mode },
+    });
+  }
+
+  async publishFallbackWarning(sessionId: string, session: SessionMode): Promise<void> {
+    session.autoModeFallbackWarningPending = false;
+    if (session.autoModeFallbackWarningShown) return;
+    session.autoModeFallbackWarningShown = true;
+    try {
+      await this.options.sessionUpdate({
+        sessionId,
+        update: noticeOrTranscriptUpdate(
+          AUTO_MODE_FALLBACK_NOTICE,
+          this.options.supportsNotices?.() ?? false,
+          noticeTranscriptText({
+            ...AUTO_MODE_FALLBACK_NOTICE,
+            description: AUTO_MODE_FALLBACK_REASON,
+          }),
+        ),
+      });
+    } catch (error) {
+      // The fallback has already been applied; a failed advisory must not turn
+      // the successful mode change into a failed request.
+      this.options.logError(`Failed to publish Auto mode fallback warning: ${error}`);
+    }
+  }
+
+  async publishFallbackState(sessionId: string, session: SessionMode): Promise<void> {
+    await this.publishCurrent(sessionId, AUTO_MODE_FALLBACK);
+    await this.publishFallbackWarning(sessionId, session);
+  }
+
+  private requireOpenSession(sessionId: string): S {
+    const session = this.options.getSession(sessionId);
+    if (!session) throw new Error("Session not found");
+    if (session.queryClosed) {
+      throw RequestError.internalError(undefined, this.options.sessionEndedMessage);
+    }
+    return session;
+  }
+
+  private isAutoUnavailable(
+    session: SessionMode,
+    modelId = session.models.currentModelId,
+  ): boolean {
+    const modelInfo = session.modelInfos.find((model) => model.value === modelId);
+    return modelInfo !== undefined && modelInfo.supportsAutoMode !== true;
+  }
+
+  private isAvailable(availableModes: SessionModeState["availableModes"], modeId: string): boolean {
+    return availableModes.some((mode) => mode.id === modeId);
+  }
+
+  private parseMode(modeId: string): PermissionMode {
+    switch (modeId) {
+      case "auto":
+      case "default":
+      case "acceptEdits":
+      case "bypassPermissions":
+      case "dontAsk":
+      case "plan":
+        return modeId;
+      default:
+        throw new Error("Invalid Mode");
+    }
+  }
+
+  private buildAvailableModes(allowBypass: boolean): SessionModeState["availableModes"] {
+    // Only AIR gets the mode kind.
+    const air = this.options.airClient?.() ?? false;
+    const kind = (value: string) => {
+      const meta = airOnlyMeta(air, AIR_KIND_KEY, value);
+      return meta ? { _meta: meta } : {};
+    };
+    const modes: SessionModeState["availableModes"] = [
+      {
+        id: "default",
+        name: "Manual",
+        description: "Always ask before making changes",
+        ...kind("standard"),
+      },
+      {
+        id: "acceptEdits",
+        name: "Accept edits",
+        description: "Automatically accept all file edits",
+        ...kind("standard"),
+      },
+      {
+        id: "plan",
+        name: "Plan",
+        description: "Create a plan before making changes",
+        ...kind("plan"),
+      },
+      {
+        id: "auto",
+        name: "Auto",
+        description: "Claude handles permission decisions",
+        ...kind("auto_review"),
+      },
+    ];
+    if (allowBypass) {
+      modes.push({
+        id: "bypassPermissions",
+        name: "Bypass permissions",
+        description: "Accepts all permissions",
+        ...kind("full_access"),
+      });
+    }
+    return modes;
+  }
+
+  private async trySyncMode(
+    query: Pick<Query, "setPermissionMode">,
+    mode: PermissionMode,
+    errorMessage: string,
+  ): Promise<void> {
+    try {
+      await query.setPermissionMode(mode);
+    } catch (error) {
+      this.options.logError(errorMessage, error);
+    }
+  }
+}

src/session-model.ts

@@ -0,0 +1,509 @@
+import type { SessionConfigOption } from "@agentclientprotocol/sdk";
+import type { ModelInfo, Query, Settings } from "@anthropic-ai/claude-agent-sdk";
+import { AIR_RECOMMENDED_CONFIG_VALUE_CAPABILITY, withAirMeta } from "./air-extension.js";
+
+export const MODEL_CONFIG_ID = "model";
+
+export type SessionModelState = {
+  availableModels: Array<{ modelId: string; name: string; description?: string }>;
+  currentModelId: string;
+};
+
+type ModelLogger = {
+  log: (...args: unknown[]) => void;
+  error: (...args: unknown[]) => void;
+};
+type ModelSettingsSource = { getSettings(): Settings };
+
+const MODEL_CONTEXT_HINT_PATTERN = /\[(\d+m)\]$/i;
+const CONTEXT_HINT_SUFFIX_PATTERN = /-(\d+m)$/i;
+const MODEL_FAMILY_VERSION_PATTERN = /\b(\d+)(?:[-.](\d+))?\b/;
+const VERSIONABLE_MODEL_DISPLAY_PATTERN =
+  /^(?:Claude\s+)?([a-z][a-z0-9-]*)(?:\s+\d+(?:\.\d+)?)?(?:\s+\(\d+[mk]\s+context\))?$/i;
+const DISPLAY_CONTEXT_SUFFIX_PATTERN = /\s+\((\d+[mk])\s+context\)$/i;
+
+function stripContextHints(value: string): string {
+  return value.replace(/\[\d+m\]/gi, "").replace(CONTEXT_HINT_SUFFIX_PATTERN, "");
+}
+
+function canonicalizeModelId(value: string): string {
+  return value.trim().toLowerCase().replace(CONTEXT_HINT_SUFFIX_PATTERN, "[$1]");
+}
+
+function contextHintOf(value: string): string | null {
+  return canonicalizeModelId(value).match(MODEL_CONTEXT_HINT_PATTERN)?.[1] ?? null;
+}
+
+function extractModelFamilyVersion(value: string): string | null {
+  const match = stripContextHints(value).match(MODEL_FAMILY_VERSION_PATTERN);
+  if (!match) return null;
+  return match[2] ? `${match[1]}.${match[2]}` : match[1];
+}
+
+function modelVersionsCompatible(preference: string, candidate: ModelInfo): boolean {
+  const preferred = extractModelFamilyVersion(preference);
+  if (!preferred) return true;
+  const candidateVersion =
+    extractModelFamilyVersion(candidate.value) ??
+    extractModelFamilyVersion(candidate.displayName) ??
+    extractModelFamilyVersion(candidate.description);
+  return candidateVersion ? preferred === candidateVersion : true;
+}
+
+function displayModelVersion(model: ModelInfo, family: string): string | undefined {
+  const familyVersion = new RegExp(`\\b${family}[-\\s]+(\\d+)(?:[-.](\\d+))?`, "i");
+  // The display name is the value we are deciding whether to rewrite, so it
+  // cannot validate its own normalization. Require independent SDK metadata.
+  for (const source of [model.resolvedModel, model.description, model.value]) {
+    const match = source?.match(familyVersion);
+    if (match) return match[2] ? `${match[1]}.${match[2]}` : match[1];
+  }
+  return undefined;
+}
+
+/** Add concrete versions when a terse SDK label names the same family as the
+ * underlying model metadata. Multi-word/custom labels remain untouched.
+ * Context size remains in the option description; if normalization would
+ * collide, callers fall back to the original labels. */
+function versionedModelDisplayName(model: ModelInfo): string {
+  const versionable = model.displayName.match(VERSIONABLE_MODEL_DISPLAY_PATTERN);
+  if (!versionable) return model.displayName;
+  const version = displayModelVersion(model, versionable[1]);
+  if (!version) return model.displayName;
+  const contextSuffix = model.displayName.match(DISPLAY_CONTEXT_SUFFIX_PATTERN);
+  const descriptionKeepsContext =
+    contextSuffix !== null &&
+    new RegExp(`\\b${contextSuffix[1]}\\s+context\\b`, "i").test(model.description);
+  const withoutContext = model.displayName.replace(DISPLAY_CONTEXT_SUFFIX_PATTERN, "");
+  if (/\b\d+(?:\.\d+)?\b/.test(withoutContext)) {
+    return descriptionKeepsContext ? withoutContext : model.displayName;
+  }
+  if (descriptionKeepsContext || contextSuffix === null) return `${withoutContext} ${version}`;
+  // Keep the suffix in its original spelling and insert the version before it.
+  return `${withoutContext} ${version}${contextSuffix[0]}`;
+}
+
+function tokenizeModelPreference(model: string): { tokens: string[]; contextHint?: string } {
+  const lower = model.trim().toLowerCase();
+  const contextHint = lower.match(MODEL_CONTEXT_HINT_PATTERN)?.[1]?.toLowerCase();
+  const tokens = lower
+    .replace(MODEL_CONTEXT_HINT_PATTERN, " $1 ")
+    .split(/[^a-z0-9]+/)
+    .filter(Boolean)
+    .map((token) => {
+      if (token === "opusplan") return "opus";
+      if (token === "best" || token === "default") return "";
+      return token;
+    })
+    .filter((token) => token && token !== "claude")
+    .filter((token) => /[a-z]/.test(token) || token.endsWith("m"));
+  return { tokens, contextHint };
+}
+
+function scoreModelMatch(model: ModelInfo, tokens: string[], contextHint?: string): number {
+  const haystack = `${model.value} ${model.displayName}`.toLowerCase();
+  let score = 0;
+  let nonHintMatched = false;
+  for (const token of tokens) {
+    if (!haystack.includes(token)) continue;
+    if (token !== contextHint) nonHintMatched = true;
+    score += token === contextHint ? 3 : 1;
+  }
+  return contextHint && !nonHintMatched ? 0 : score;
+}
+
+export function resolveModelPreference(models: ModelInfo[], preference: string): ModelInfo | null {
+  const trimmed = preference.trim();
+  if (!trimmed) return null;
+  const lower = trimmed.toLowerCase();
+  const canonicalPreference = canonicalizeModelId(trimmed);
+  const directMatch = models.find(
+    (model) =>
+      model.value === trimmed ||
+      canonicalizeModelId(model.value) === canonicalPreference ||
+      model.displayName.toLowerCase() === lower,
+  );
+  if (directMatch) return directMatch;
+
+  const matchesResolved = (model: ModelInfo) =>
+    model.resolvedModel != null && canonicalizeModelId(model.resolvedModel) === canonicalPreference;
+  const resolvedMatch =
+    models.find((model) => model.value !== "default" && matchesResolved(model)) ??
+    models.find(matchesResolved);
+  if (resolvedMatch) return resolvedMatch;
+
+  const preferenceHint = contextHintOf(trimmed);
+  const includesMatch = models.find((model) => {
+    if (!modelVersionsCompatible(trimmed, model)) return false;
+    if (contextHintOf(model.value) !== preferenceHint) return false;
+    const value = model.value.toLowerCase();
+    const display = model.displayName.toLowerCase();
+    return value.includes(lower) || display.includes(lower) || lower.includes(value);
+  });
+  if (includesMatch) return includesMatch;
+
+  const { tokens, contextHint } = tokenizeModelPreference(trimmed);
+  if (tokens.length === 0) return null;
+  let bestMatch: ModelInfo | null = null;
+  let bestScore = 0;
+  for (const model of models) {
+    if (!modelVersionsCompatible(trimmed, model)) continue;
+    const score = scoreModelMatch(model, tokens, contextHint);
+    if (score > 0 && (!bestMatch || score > bestScore)) {
+      bestMatch = model;
+      bestScore = score;
+    }
+  }
+  return bestMatch;
+}
+
+export function matchResumedModel(models: ModelInfo[], liveModel: string): ModelInfo {
+  const live = canonicalizeModelId(liveModel);
+  const defaultEntry = models.find((model) => model.value === "default");
+  const defaultResolved = defaultEntry?.resolvedModel
+    ? canonicalizeModelId(defaultEntry.resolvedModel)
+    : undefined;
+  if (defaultEntry && defaultResolved === live) return defaultEntry;
+  const exactMatch = models.find(
+    (model) => model.resolvedModel && canonicalizeModelId(model.resolvedModel) === live,
+  );
+  if (exactMatch) return exactMatch;
+  if (
+    defaultEntry &&
+    defaultResolved &&
+    stripContextHints(defaultResolved) === stripContextHints(live)
+  ) {
+    return defaultEntry;
+  }
+  return (
+    resolveModelPreference(models, liveModel) ?? {
+      value: liveModel,
+      displayName: liveModel,
+      description: "",
+    }
+  );
+}
+
+export function buildModelConfigOption(
+  models: SessionModelState,
+  modelInfos: ModelInfo[],
+  useRecommendedValue: boolean,
+): SessionConfigOption {
+  const defaultInfo = modelInfos.find((model) => model.value === "default");
+  const selectableIds = new Set(models.availableModels.map((model) => model.modelId));
+  const concreteInfos = modelInfos.filter(
+    (model) => model.value !== "default" && selectableIds.has(model.value),
+  );
+  // Recommendations describe the running default, so fuzzy family matching
+  // must never substitute a different generation or context window.
+  const defaultResolved = defaultInfo?.resolvedModel;
+  const recommended = defaultResolved
+    ? (concreteInfos.find(
+        (model) =>
+          canonicalizeModelId(model.resolvedModel ?? model.value) ===
+          canonicalizeModelId(defaultResolved),
+      ) ?? null)
+    : null;
+  const concreteRecommendation = useRecommendedValue && recommended !== null;
+  const available = concreteRecommendation
+    ? models.availableModels.filter((model) => model.modelId !== "default")
+    : models.availableModels;
+
+  return {
+    id: MODEL_CONFIG_ID,
+    name: "Model",
+    description: "AI model to use",
+    category: "model",
+    type: "select",
+    currentValue:
+      concreteRecommendation && models.currentModelId === "default"
+        ? recommended.value
+        : models.currentModelId,
+    ...(concreteRecommendation
+      ? {
+          _meta: withAirMeta(undefined, AIR_RECOMMENDED_CONFIG_VALUE_CAPABILITY, recommended.value),
+        }
+      : {}),
+    options: available.map((model) => {
+      if (model.modelId === "default" && defaultInfo?.resolvedModel) {
+        const named = modelInfos.find(
+          (info) => info.value !== "default" && info.resolvedModel === defaultInfo.resolvedModel,
+        );
+        return {
+          value: model.modelId,
+          name: model.name,
+          description: named?.displayName ?? defaultInfo.resolvedModel,
+        };
+      }
+      return {
+        value: model.modelId,
+        name: model.name,
+        description: model.description ?? undefined,
+      };
+    }),
+  };
+}
+
+function resolveSettingsModel(
+  models: ModelInfo[],
+  settingsModel: unknown,
+  logger: ModelLogger,
+): ModelInfo | null {
+  if (settingsModel === undefined) {
+    return null;
+  }
+  if (typeof settingsModel !== "string") {
+    const typeLabel = settingsModel === null ? "null" : typeof settingsModel;
+    logger.error(`Ignoring model from settings: expected a string, got ${typeLabel}.`);
+    return null;
+  }
+  return resolveModelPreference(models, settingsModel);
+}
+
+const MODEL_FAMILY_ALIASES = new Set(["opus", "sonnet", "haiku", "fable"]);
+
+/** A model id without the spellings `deniedModels` ignores: provider
+ *  prefixes, dates, version suffixes, `-fast` and context hints. */
+function normalizeDeniedModelId(value: string): string {
+  let id = stripContextHints(value.trim().toLowerCase());
+  const providerPrefix = id.lastIndexOf("anthropic.");
+  if (providerPrefix !== -1) id = id.slice(providerPrefix + "anthropic.".length);
+  return id
+    .replace(/@.*$/, "")
+    .replace(/-v\d+(?::\d+)?$/, "")
+    .replace(/-fast$/, "")
+    .replace(/-\d{8}$/, "");
+}
+
+/**
+ * Whether managed `deniedModels` blocks a model id, following the CLI's rules
+ * closely enough for the picker: a family alias blocks the whole family, and a
+ * model id blocks that version in every spelling plus the later minor versions
+ * it prefixes (`claude-opus-5` also blocks `claude-opus-5-5`). The CLI stays
+ * the enforcer; this only keeps the picker from offering a refused row.
+ */
+export function isDeniedModel(modelId: string, deniedModels: readonly string[]): boolean {
+  const id = normalizeDeniedModelId(modelId);
+  if (!id) return false;
+  return deniedModels.some((entry) => {
+    const denied = normalizeDeniedModelId(entry);
+    if (!denied) return false;
+    if (MODEL_FAMILY_ALIASES.has(denied)) return id === denied || id.includes(`-${denied}`);
+    return id === denied || id.startsWith(`${denied}-`);
+  });
+}
+
+/**
+ * Restrict the SDK's model list to the user's `availableModels` allowlist
+ * (already merged-and-deduped across settings sources by `SettingsManager`).
+ * The user's exact entries become the model IDs surfaced via configOptions
+ * and passed to `setModel`, which prevents Claude Code from silently
+ * substituting a date-pinned variant (e.g. `haiku` →
+ * `claude-haiku-4-5-20251001`) that the user may not have access to.
+ *
+ * Display info and capability flags are copied from the closest SDK match so
+ * the UI still renders sensible names and effort levels.
+ *
+ * Semantics from https://code.claude.com/docs/en/model-config#restrict-model-selection:
+ * - `undefined` is handled by the caller (no allowlist applied).
+ * - The Default option is unaffected by `availableModels` — it always remains
+ *   available, even when the allowlist is `[]`.
+ * - Managed `deniedModels` wins over the allowlist, so a denied entry is
+ *   dropped even though the CLI would otherwise leave it unmatched.
+ */
+export function applyAvailableModelsAllowlist(
+  sdkModels: ModelInfo[],
+  allowlist: string[],
+  settingsModelOverrides?: Record<string, string>,
+  deniedModels: readonly string[] = [],
+): ModelInfo[] {
+  // Default is always preserved per the docs. Synthesize one if the SDK
+  // didn't surface it so downstream code (e.g. `getAvailableModels` picking
+  // `models[0]` as a fallback) still has something to work with.
+  const defaultModel = sdkModels.find((m) => m.value === "default") ?? {
+    value: "default",
+    displayName: "Default",
+    description: "",
+  };
+  const result: ModelInfo[] = [defaultModel];
+  const seen = new Set<string>([defaultModel.value]);
+
+  const sdkModelsWithoutDefault = sdkModels.filter((m) => m.value !== "default");
+
+  // Bedrock/Vertex deployments enforce short aliases (e.g. "claude-opus-4-6")
+  // in availableModels but require provider-specific IDs at the API. We still
+  // resolve `sdkMatch` against the alias (`trimmed`) — that's what the
+  // matching heuristics above are built for, and override targets (ARNs,
+  // opaque provider IDs) often won't textually resemble anything in
+  // `sdkModelsWithoutDefault`. Only the entry's surfaced `value` becomes the
+  // override target, so it's what `setModel` ends up passing to the API.
+  for (const entry of allowlist) {
+    const trimmed = entry.trim();
+    if (!trimmed || seen.has(trimmed)) continue;
+
+    const overridden = settingsModelOverrides?.[trimmed];
+    const effective = overridden ?? trimmed;
+    if (seen.has(effective)) continue;
+
+    const sdkMatch = resolveModelPreference(sdkModelsWithoutDefault, trimmed);
+    if (
+      [trimmed, effective, sdkMatch?.resolvedModel].some(
+        (id) => id != null && isDeniedModel(id, deniedModels),
+      )
+    ) {
+      continue;
+    }
+    if (sdkMatch) {
+      result.push({ ...sdkMatch, value: effective });
+    } else {
+      result.push({ value: effective, displayName: trimmed, description: "" });
+    }
+    seen.add(effective);
+  }
+
+  // The custom model option (ANTHROPIC_CUSTOM_MODEL_OPTION) is exempt from the
+  // allowlist, the same way Default is. Per the model-config docs it adds an
+  // entry "without replacing the built-in aliases" and "appears at the bottom of
+  // the /model picker", so we append it last and skip the allowlist filter; this
+  // keeps a slim alias allowlist from hiding the custom model row.
+  // https://code.claude.com/docs/en/model-config#add-a-custom-model-option
+  const customModelOption = process.env.ANTHROPIC_CUSTOM_MODEL_OPTION?.trim();
+  if (customModelOption && !seen.has(customModelOption)) {
+    const customModel = sdkModels.find((m) => m.value === customModelOption);
+    if (customModel) {
+      result.push(customModel);
+      seen.add(customModel.value);
+    }
+  }
+
+  return result;
+}
+
+/** Whether a rejected `setModel` was vetoed by a user-configured
+ *  PreModelSwitch hook. The CLI's rejection message is the stable,
+ *  distinguishable marker ("Model switch blocked by a PreModelSwitch hook:
+ *  <reason>"); a format change makes this stop matching and the failure
+ *  falls back to the ordinary fail-loud path, no worse than before. */
+function isPreModelSwitchHookBlock(error: unknown): boolean {
+  return error instanceof Error && error.message.includes("blocked by a PreModelSwitch hook");
+}
+
+export async function getAvailableModels(
+  query: Query,
+  models: ModelInfo[],
+  sdkModels: ModelInfo[],
+  settingsManager: ModelSettingsSource,
+  logger: ModelLogger,
+  isResumedSession: boolean,
+  sessionId: string,
+  resumedModelHint?: string,
+): Promise<SessionModelState> {
+  const settings = settingsManager.getSettings();
+
+  let currentModel = models[0];
+  let resolvedFromInput: string | undefined;
+  // Model priority (highest to lowest):
+  // 1. ANTHROPIC_MODEL environment variable
+  // 2. settings.model (user configuration)
+  // 3. the resumed session's live model (resumed sessions only)
+  // 4. models[0] (default first model)
+  if (process.env.ANTHROPIC_MODEL) {
+    const match = resolveModelPreference(models, process.env.ANTHROPIC_MODEL);
+    if (match) {
+      currentModel = match;
+      resolvedFromInput = process.env.ANTHROPIC_MODEL;
+    }
+  } else if (typeof settings.model === "string") {
+    const match = resolveSettingsModel(models, settings.model, logger);
+    if (match) {
+      currentModel = match;
+      resolvedFromInput = settings.model;
+    }
+  }
+
+  // A resumed session restores the model from its last real assistant
+  // transcript record. Use that same local record instead of getContextUsage:
+  // the latter is a control request to the live CLI process and can add tens
+  // of seconds to session/load before its first turn. No `setModel` here: the
+  // SDK is already running this model, and pushing a picker alias back (e.g.
+  // "opus[1m]") could change the live model rather than describe it.
+  if (resolvedFromInput === undefined && isResumedSession) {
+    currentModel = resumedModelHint ? matchResumedModel(models, resumedModelHint) : currentModel;
+  }
+
+  // Skip the setModel round-trip when we can prove the SDK has already landed
+  // on the same model. Two cases qualify:
+  //  (a) No override applied — currentModel is the SDK's own default (or, on
+  //      resume, the live model read back from the SDK above); nothing to sync.
+  //  (b) The resolver returned the user's input verbatim AND that value exists
+  //      in the SDK's original model list — meaning no fuzzy match or
+  //      allowlist rewrite was involved, and the SDK (which reads the same
+  //      ANTHROPIC_MODEL / settings.json) will have arrived at the same entry.
+  //      This only holds for fresh sessions: a resumed session lands on the
+  //      transcript's model regardless of env/settings, so the override must
+  //      be re-asserted to keep the reported model truthful.
+  // Anything else (fuzzy match, allowlist-synthesized value, alias) gets a
+  // setModel call so we don't drift from the user's intended pin.
+  const sdkSawSameValue = sdkModels.some((m) => m.value === currentModel.value);
+  const skipSetModel =
+    resolvedFromInput === undefined ||
+    (!isResumedSession && currentModel.value === resolvedFromInput && sdkSawSameValue);
+  if (!skipSetModel) {
+    const setModelStartedAt = performance.now();
+    try {
+      await query.setModel(currentModel.value);
+      logger.log(
+        `[session/models] sessionId=${sessionId} phase=set-model durationMs=${Math.round(performance.now() - setModelStartedAt)} model=${currentModel.value} outcome=success`,
+      );
+    } catch (error) {
+      logger.log(
+        `[session/models] sessionId=${sessionId} phase=set-model durationMs=${Math.round(performance.now() - setModelStartedAt)} model=${currentModel.value} outcome=error`,
+      );
+      // On a fresh session the pin is a defining option — fail loudly. A
+      // resumed session already runs fine on the transcript's model, so
+      // failing the whole session/load over the re-assert would be worse
+      // than loading with the pin unapplied (mirrors the setPermissionMode
+      // containment in createSession). The SDK then stayed on the
+      // transcript's model, so read that back rather than reporting the
+      // pin the session isn't running.
+      //
+      // One fresh-session failure is advisory, not defining: a
+      // user-configured PreModelSwitch hook can veto the pin (CLI 2.1.251+;
+      // 'deny', or 'ask' — which headless sessions refuse), and the SDK
+      // rejects setModel with "Model switch blocked by a PreModelSwitch
+      // hook: …". Terminal Claude Code never lets a hook veto its startup
+      // model (the spawn model isn't a switch), so failing session/new here
+      // would make the same hook config fatal only over ACP. The session
+      // stays on the SDK's own default — report that. We can't read the
+      // live model back on this path: getContextUsage isn't serviced on a
+      // fresh session until the first prompt turn (issues #886/#880).
+      if (!isResumedSession) {
+        if (!isPreModelSwitchHookBlock(error)) throw error;
+        logger.error(
+          `Model pin "${currentModel.value}" was vetoed by a PreModelSwitch hook; staying on the default model:`,
+          error,
+        );
+        currentModel = models[0];
+      } else {
+        logger.error(`Failed to re-assert model "${currentModel.value}" on resume:`, error);
+        currentModel = resumedModelHint ? matchResumedModel(models, resumedModelHint) : models[0];
+      }
+    }
+  }
+
+  const displayNames = models.map(versionedModelDisplayName);
+  const displayNameCounts = new Map<string, number>();
+  for (const name of displayNames) {
+    displayNameCounts.set(name, (displayNameCounts.get(name) ?? 0) + 1);
+  }
+
+  return {
+    availableModels: models.map((model, index) => ({
+      modelId: model.value,
+      name:
+        displayNameCounts.get(displayNames[index]) === 1 ? displayNames[index] : model.displayName,
+      description: model.description,
+    })),
+    currentModelId: currentModel.value,
+  };
+}

src/session-notices.ts

@@ -0,0 +1,96 @@
+import type { ClientCapabilities, SessionNotification } from "@agentclientprotocol/sdk";
+
+/** Fire-and-forget advisory text for the user: live events rather than
+ *  conversation history. See the ACP Session Notices RFD
+ *  (https://agentclientprotocol.com/rfds/session-notices). */
+export type SessionNotice = {
+  severity: "info" | "warning" | "error";
+  /** Plain text that stands alone. */
+  title: string;
+  /** Plain-text detail or guidance. */
+  description?: string;
+};
+
+/** Longest free-form line that may serve as a notice title on its own. Past
+ *  this the text moves to `description` under a generic title. */
+export const MAX_NOTICE_TITLE_LENGTH = 256;
+
+/** Whether the Client advertised `clientCapabilities.session.notices`. Agents
+ *  MUST NOT send `notice` updates otherwise; the alternative is a bold-label
+ *  transcript line, which was the only way to flag these before. */
+export function clientSupportsNotices(capabilities?: ClientCapabilities | null): boolean {
+  const notices = capabilities?.session?.notices;
+  return typeof notices === "object" && notices !== null && !Array.isArray(notices);
+}
+
+export function noticeUpdate(notice: SessionNotice): SessionNotification["update"] {
+  return {
+    sessionUpdate: "notice",
+    severity: notice.severity,
+    title: notice.title,
+    ...(notice.description ? { description: notice.description } : {}),
+  };
+}
+
+/** The transcript rendering of a notice for clients without the capability. */
+export function noticeTranscriptText(notice: SessionNotice): string {
+  return notice.description ? `**${notice.title}:** ${notice.description}` : `**${notice.title}**`;
+}
+
+/** The update to send for `notice`: a `notice` when the client can present
+ *  one, else an agent message carrying `transcriptText` (by default the
+ *  bold-label rendering of the notice) and `transcriptMeta`, so clients
+ *  without the capability can still tell the line apart from Claude's reply. */
+export function noticeOrTranscriptUpdate(
+  notice: SessionNotice,
+  supportsNotices: boolean,
+  transcriptText: string = noticeTranscriptText(notice),
+  transcriptMeta?: Record<string, unknown>,
+): SessionNotification["update"] {
+  if (supportsNotices) return noticeUpdate(notice);
+  return {
+    sessionUpdate: "agent_message_chunk",
+    content: { type: "text", text: transcriptText },
+    ...(transcriptMeta ? { _meta: transcriptMeta } : {}),
+  };
+}
+
+/** Fragments that read on after a bold label stand alone as a notice
+ *  description, so start them with a capital. */
+export function sentenceCase(text: string): string {
+  return text.charAt(0).toUpperCase() + text.slice(1);
+}
+
+/** Collapses whitespace so a text shown as a notice can be recognized when
+ *  the SDK repeats it elsewhere (a hook-blocked turn's result, for one). */
+export function normalizeNoticeText(text: string): string {
+  return text.trim().replace(/\s+/g, " ");
+}
+
+/** Notice fields are plain text. Free-form SDK/hook output may carry light
+ *  markdown that a transcript would render; drop the inline markers rather
+ *  than show literal asterisks and backticks in a toast. */
+export function noticePlainText(text: string): string {
+  return text
+    .replace(/^[ \t]*#{1,6}[ \t]+/gm, "")
+    .replace(/(\*\*|__)(?=\S)([\s\S]*?\S)\1/g, "$2")
+    .replace(/(?<![\w`])`([^`\n]+)`(?![\w`])/g, "$1");
+}
+
+/** Shapes free-form text into a notice title plus optional description: the
+ *  first line stands as the title when it is short enough, otherwise the whole
+ *  text becomes the description under `fallbackTitle`. */
+export function splitNoticeText(
+  text: string,
+  fallbackTitle: string,
+): Pick<SessionNotice, "title" | "description"> {
+  const trimmed = noticePlainText(text).trim();
+  if (!trimmed) return { title: fallbackTitle };
+  const lineBreak = trimmed.search(/\r?\n/);
+  const firstLine = lineBreak === -1 ? trimmed : trimmed.slice(0, lineBreak).trimEnd();
+  const rest = lineBreak === -1 ? "" : trimmed.slice(lineBreak).trim();
+  if (firstLine.length > MAX_NOTICE_TITLE_LENGTH) {
+    return { title: fallbackTitle, description: trimmed };
+  }
+  return rest ? { title: firstLine, description: rest } : { title: firstLine };
+}

src/session-timing.ts

@@ -0,0 +1,27 @@
+type TimingLogger = {
+  log: (...args: unknown[]) => void;
+};
+
+/** Small phase timer for session lifecycle diagnostics. */
+export class SessionTiming {
+  private readonly startedAt: number;
+  private phaseStartedAt: number;
+
+  constructor(
+    private readonly logger: TimingLogger | undefined,
+    private readonly operation: string,
+    private readonly sessionId: string,
+    startedAt = performance.now(),
+  ) {
+    this.startedAt = startedAt;
+    this.phaseStartedAt = startedAt;
+  }
+
+  phase(name: string, detail = ""): void {
+    const finishedAt = performance.now();
+    this.logger?.log(
+      `[session/${this.operation}] sessionId=${this.sessionId} phase=${name} durationMs=${Math.round(finishedAt - this.phaseStartedAt)} totalMs=${Math.round(finishedAt - this.startedAt)}${detail}`,
+    );
+    this.phaseStartedAt = finishedAt;
+  }
+}

src/session-titles.ts

@@ -0,0 +1,246 @@
+/**
+ * AI-generated session titles.
+ *
+ * Claude Code's own auto-title generation never runs under the Agent SDK — the
+ * latch that arms it is pre-set in the headless path — so `SDKSessionInfo.summary`
+ * degrades to the raw first prompt. This module asks the CLI for a real title
+ * instead, via the `generate_session_title` control request, and publishes it
+ * over ACP as a `session_info_update`.
+ *
+ * {@link SessionTitles} holds the per-session state and is owned by `Session`.
+ * `acp-agent.ts` drives it from four places: {@link SessionTitles.onPrompt} and
+ * {@link SessionTitles.onAssistantText} to collect text,
+ * {@link SessionTitles.onTurnEnd} at `session_state_changed: idle`, and
+ * {@link SessionTitles.reset} on `conversation_reset`.
+ */
+
+import type { ContentBlock, PromptRequest } from "@agentclientprotocol/sdk";
+import { getSessionInfo, type Query, type SDKSessionInfo } from "@anthropic-ai/claude-agent-sdk";
+import type { ClaudeAcpAgent, Session } from "./acp-agent.js";
+
+const MAX_TITLE_LENGTH = 256;
+
+/** How much session text the title is generated from. The CLI caps its own
+ *  title input at the same 1000 trailing characters. */
+const MAX_TITLE_CONTEXT_LENGTH = 1000;
+
+/** Below this the generator returns null without calling the model, so there is
+ *  nothing to gain by asking yet. */
+const MIN_TITLE_CONTEXT_LENGTH = 10;
+
+/** `generateSessionTitle` is present on the SDK's runtime `Query` class but is
+ *  not declared in `sdk.d.ts` (0.3.220), so it is reached through this optional
+ *  shape rather than the published interface. */
+type TitleCapableQuery = Query & {
+  generateSessionTitle?: (
+    description: string,
+    options?: { persist?: boolean },
+  ) => Promise<string | null>;
+};
+
+/** A title already stored for the session, published when generation is
+ *  unavailable or yields nothing. */
+type TitleFallback = { title: string; lastModified: number };
+
+export function sanitizeTitle(text: string): string {
+  // Replace newlines and collapse whitespace
+  const sanitized = text
+    .replace(/[\r\n]+/g, " ")
+    .replace(/\s+/g, " ")
+    .trim();
+  if (sanitized.length <= MAX_TITLE_LENGTH) {
+    return sanitized;
+  }
+  return sanitized.slice(0, MAX_TITLE_LENGTH - 1) + "…";
+}
+
+/** Rolling text a title is generated from: `previous` plus `text`, keeping only
+ *  the trailing {@link MAX_TITLE_CONTEXT_LENGTH} characters. */
+export function appendTitleContext(previous: string | undefined, text: string): string {
+  const next = (previous ?? "") + text;
+  return next.length > MAX_TITLE_CONTEXT_LENGTH ? next.slice(-MAX_TITLE_CONTEXT_LENGTH) : next;
+}
+
+/** Whether this SDK still offers on-demand title generation. */
+function supportsTitleGeneration(query: Query): boolean {
+  return typeof (query as TitleCapableQuery).generateSessionTitle === "function";
+}
+
+/** One session's title: the text a generated title is derived from, whether a
+ *  title has been settled on, and the last one published. Created with the
+ *  session and reachable as `session.titles`. */
+export class SessionTitles {
+  /** Last title pushed to the client via `session_info_update`, so an unchanged
+   *  title is never re-notified. Undefined until the first push. */
+  private lastTitle?: string;
+
+  /** Rolling tail of this session's own user + assistant text, capped at
+   *  {@link MAX_TITLE_CONTEXT_LENGTH}. Dropped once a title exists. */
+  private context?: string;
+
+  /** Set once this session has a title or has asked for one. A title is
+   *  generated at most once per session: the SDK reports a generated title in
+   *  the same field as a user `/rename`, so re-titling could silently overwrite
+   *  one. Released by {@link reset}, and when generation yields nothing. */
+  private settled = false;
+
+  constructor(
+    private readonly agent: ClaudeAcpAgent,
+    private readonly sessionId: string,
+  ) {}
+
+  /** Collect a prompt's own text for the title, skipping openers not worth
+   *  titling after. No-op once the title is settled. */
+  onPrompt(prompt: PromptRequest["prompt"]): void {
+    if (this.settled) {
+      return;
+    }
+    const promptText = prompt
+      .flatMap((chunk) => (chunk.type === "text" ? [chunk.text] : []))
+      .join("\n");
+
+    this.context = appendTitleContext(this.context, `\n${promptText}\n`);
+  }
+
+  /** Collect the assistant's own answer for the title. Chunks are appended
+   *  verbatim so streamed text reassembles. No-op once the title is settled. */
+  onAssistantText(content: ContentBlock): void {
+    if (this.settled || content.type !== "text") {
+      return;
+    }
+    this.context = appendTitleContext(this.context, content.text);
+  }
+
+  /** Drop the title state so the next turn re-evaluates. Used on
+   *  `conversation_reset`, which mounts a fresh transcript. */
+  reset(): void {
+    this.settled = false;
+    this.context = undefined;
+    this.lastTitle = undefined;
+  }
+
+  /** Turn-end title handling. `idle` is the SDK's turn-over signal, so it is
+   *  when a title may have landed or become generatable.
+   *
+   *  `info.customTitle` is non-empty only once the session file holds a real
+   *  title — a user `/rename` or one generated earlier; the SDK folds both into
+   *  that one field. Adopt it and latch, so neither is ever titled over.
+   *
+   *  With no title yet, ask the SDK to generate one in the background: it is a
+   *  ~2s small-model call and turn-end must not wait on it. Only when that is
+   *  not possible do we fall back to `summary`, which for an SDK-driven session
+   *  is just the raw first prompt. */
+  async onTurnEnd(session: Session): Promise<void> {
+    const info = await this.readSessionInfo(session);
+
+    if (info?.customTitle) {
+      this.settled = true;
+      this.context = undefined;
+      await this.publish(info.customTitle, info.lastModified);
+      return;
+    }
+
+    const fallback = info?.summary
+      ? { title: info.summary, lastModified: info.lastModified }
+      : undefined;
+
+    if (this.canRequest(session)) {
+      this.settled = true;
+
+      void this.requestGenerateTitle(session, fallback).catch((error) => {
+        this.agent.logger.error(`Session ${this.sessionId}: session title update failed: ${error}`);
+      });
+
+      return;
+    }
+    // Only while this session has no title of its own: `summary` degrades to the
+    // raw first prompt, which must never overwrite a generated title if the
+    // persisted one is slow to show up in `info`.
+    if (fallback && !this.settled) {
+      await this.publish(fallback.title, fallback.lastModified);
+    }
+  }
+
+  /** Read the SDK's stored info for this session. A missing session file or read
+   *  error is non-fatal: the title is best-effort and another turn will retry. */
+  private async readSessionInfo(session: Session): Promise<SDKSessionInfo | undefined> {
+    try {
+      return await getSessionInfo(this.sessionId, { dir: session.cwd });
+    } catch (error) {
+      this.agent.logger.error(`Session ${this.sessionId}: failed to read session info: ${error}`);
+      return undefined;
+    }
+  }
+
+  /** Notify the client of a title, unless it is the one we last sent. */
+  private async publish(rawTitle: string, lastModified: number): Promise<void> {
+    const title = sanitizeTitle(rawTitle);
+    if (title === this.lastTitle) {
+      return;
+    }
+    this.lastTitle = title;
+    await this.agent.client.sessionUpdate({
+      sessionId: this.sessionId,
+      update: {
+        sessionUpdate: "session_info_update",
+        title,
+        updatedAt: new Date(lastModified).toISOString(),
+      },
+    });
+  }
+
+  /** Whether to ask the SDK for a generated title now: once per session, on a
+   *  live query, with enough collected text for the generator to work with. */
+  private canRequest(session: Session): boolean {
+    if (this.settled || session.queryClosed || session.cancelled) {
+      return false;
+    }
+    if (!supportsTitleGeneration(session.query)) {
+      return false;
+    }
+    return (this.context?.trim().length ?? 0) >= MIN_TITLE_CONTEXT_LENGTH;
+  }
+
+  /** Generate a title from the session's own text and publish it. `persist`
+   *  writes it to the session file, which is what carries it into
+   *  `session/list` and `session/load`. A null or failed generation releases the
+   *  latch so a later turn retries, and publishes `fallback` (the stored
+   *  summary) so a backend that can't generate titles is no worse off than
+   *  before. */
+  private async requestGenerateTitle(
+    session: Session,
+    fallback: TitleFallback | undefined,
+  ): Promise<void> {
+    const description = this.context?.trim() ?? "";
+    let title: string | null = null;
+
+    try {
+      title =
+        (await (session.query as TitleCapableQuery).generateSessionTitle?.(description, {
+          persist: true,
+        })) ?? null;
+    } catch (error) {
+      this.agent.logger.error(
+        `Session ${this.sessionId}: failed to generate a session title: ${error}`,
+      );
+    }
+
+    // A session torn down or replaced while the title was in flight must not
+    // adopt it.
+    if (this.agent.sessions[this.sessionId] !== session) {
+      return;
+    }
+
+    if (!title) {
+      this.settled = false;
+
+      if (fallback) {
+        await this.publish(fallback.title, fallback.lastModified);
+      }
+      return;
+    }
+
+    this.context = undefined;
+    await this.publish(title, Date.now());
+  }
+}

src/settings.ts

@@ -7,7 +7,7 @@ import {
   resolveSettings,
   type Settings,
 } from "@anthropic-ai/claude-agent-sdk";
-import { CLAUDE_CONFIG_DIR } from "./acp-agent.js";
+import { claudeConfigDir } from "./paths.js";
 
 /**
  * Permission rule format examples:
@@ -49,6 +49,7 @@ export interface SettingsManagerOptions {
 export class SettingsManager {
   private cwd: string;
   private effective: Settings = {};
+  private managedDeniedModels: string[] = [];
   private watchers: fs.FSWatcher[] = [];
   private onChange?: () => void;
   private logger: { log: (...args: any[]) => void; error: (...args: any[]) => void };
@@ -91,7 +92,7 @@ export class SettingsManager {
    */
   private getWatchedPaths(): string[] {
     return [
-      path.join(CLAUDE_CONFIG_DIR, "settings.json"),
+      path.join(claudeConfigDir(), "settings.json"),
       path.join(this.cwd, ".claude", "settings.json"),
       path.join(this.cwd, ".claude", "settings.local.json"),
       getManagedSettingsPath(),
@@ -106,9 +107,14 @@ export class SettingsManager {
     try {
       const resolved = await resolveSettings({ cwd: this.cwd });
       this.effective = filterEscalatingDefaultMode(resolved);
+      // The CLI reads `deniedModels` from managed settings only.
+      this.managedDeniedModels = resolved.sources
+        .filter((entry) => entry.source === "managed")
+        .flatMap((entry) => entry.settings.deniedModels ?? []);
     } catch (error) {
       this.logger.error("Failed to resolve settings:", error);
       this.effective = {};
+      this.managedDeniedModels = [];
     }
   }
 
@@ -171,6 +177,14 @@ export class SettingsManager {
     return this.effective;
   }
 
+  /**
+   * `deniedModels` entries from the managed tier, the only tier the CLI
+   * honors them from.
+   */
+  getManagedDeniedModels(): string[] {
+    return this.managedDeniedModels;
+  }
+
   /**
    * Returns the current working directory
    */

src/subagent-history.ts

@@ -0,0 +1,54 @@
+import { getSessionInfo } from "@anthropic-ai/claude-agent-sdk";
+import { readdir, readFile } from "node:fs/promises";
+import path from "node:path";
+import { findTranscript } from "./resumed-session.js";
+
+/** Where the subagent transcripts of a session are. */
+export interface SubagentHistory {
+  /** The subagent id of each Agent or Task tool use that launched a subagent. */
+  ids: Map<string, string>;
+  /**
+   * The project directory of the session, as the SDK takes it in `dir`. With
+   * it, the SDK reads a subagent transcript without a search of every project.
+   */
+  dir?: string;
+}
+
+/**
+ * Finds the subagent transcripts of a session.
+ *
+ * Claude keeps the history of a subagent in its own transcript,
+ * `<session>/subagents/agent-<id>.jsonl`, next to the session transcript.
+ * The `agent-<id>.meta.json` file beside it names the launching tool use.
+ * The ids are empty for a session without a local transcript.
+ */
+export async function subagentHistory(sessionId: string): Promise<SubagentHistory> {
+  const ids = new Map<string, string>();
+  const transcript = await findTranscript(sessionId);
+  if (!transcript) return { ids };
+  const directory = path.join(path.dirname(transcript), sessionId, "subagents");
+  let names: string[];
+  try {
+    names = await readdir(directory);
+  } catch {
+    return { ids };
+  }
+  await Promise.all(
+    names.map(async (name) => {
+      const match = /^agent-(.+)\.meta\.json$/.exec(name);
+      if (!match) return;
+      try {
+        const meta: unknown = JSON.parse(await readFile(path.join(directory, name), "utf8"));
+        const toolUseId = (meta as { toolUseId?: unknown } | null)?.toolUseId;
+        if (typeof toolUseId === "string") ids.set(toolUseId, match[1]!);
+      } catch {
+        // A damaged meta file leaves its subagent without history.
+      }
+    }),
+  );
+  if (ids.size === 0) return { ids };
+  // The folder name encodes the project directory, and the encoding loses
+  // characters. The session info reads it back from the transcript.
+  const dir = (await getSessionInfo(sessionId).catch(() => undefined))?.cwd;
+  return dir ? { ids, dir } : { ids };
+}

src/tests/acp-agent-settings.test.ts

@@ -94,7 +94,119 @@ describe("ClaudeAcpAgent settings", () => {
 
     expect(getCapturedOptions().permissionMode).toBe("dontAsk");
     expect(getCapturedOptions().settingSources).toEqual(["user", "project", "local"]);
-    expect(response.modes.currentModeId).toBe("dontAsk");
+    expect(response.modes.currentModeId).toBe("default");
+  }, 15_000);
+
+  it.each([
+    { recommended: false, setting: undefined, explicit: undefined, expected: "default" },
+    { recommended: false, setting: "low", explicit: "high", expected: "high" },
+    { recommended: true, setting: undefined, explicit: undefined, expected: "medium" },
+    { recommended: true, setting: "high", explicit: undefined, expected: "high" },
+    { recommended: true, setting: "high", explicit: "max", expected: "max" },
+  ])(
+    "initial effort reflects SDK state: %j",
+    async ({ recommended, setting, explicit, expected }) => {
+      await fs.promises.writeFile(
+        path.join(tempDir, "settings.json"),
+        JSON.stringify({ effortLevel: setting }),
+      );
+      const applyFlagSettings = vi.fn();
+      querySpy.mockReturnValue(
+        makeMockQuery({
+          initializationResult: async () => ({
+            models: [
+              {
+                value: "default",
+                displayName: "Default",
+                description: "",
+                supportsEffort: true,
+                supportedEffortLevels: ["low", "medium", "high", "max"],
+              },
+            ],
+          }),
+          applyFlagSettings,
+        }),
+      );
+      const { ClaudeAcpAgent } = await import("../acp-agent.js");
+      const agent = new ClaudeAcpAgent(createMockClient());
+      if (recommended) {
+        (agent as any).clientCapabilities = {
+          _meta: { jetbrains: { air: { version: 1, capabilities: ["recommendedValue"] } } },
+        };
+      }
+      const response = await (agent as any).createSession({
+        cwd: tempDir,
+        mcpServers: [],
+        _meta: { disableBuiltInTools: true, claudeCode: { options: { effort: explicit } } },
+      });
+      expect(
+        response.configOptions.find((option: any) => option.id === "effort").currentValue,
+      ).toBe(expected);
+      if (recommended) {
+        expect(applyFlagSettings).toHaveBeenCalledWith({ effortLevel: expected });
+      } else {
+        expect(applyFlagSettings).not.toHaveBeenCalled();
+      }
+      expect(agent.sessions[response.sessionId].effortPinnedLevel).toBe(explicit);
+      expect(agent.sessions[response.sessionId].appliedEffortLevel).toBe(
+        recommended ? expected : explicit,
+      );
+    },
+  );
+
+  it("seeds effort from higher-priority programmatic model settings", async () => {
+    await fs.promises.writeFile(
+      path.join(tempDir, "settings.json"),
+      JSON.stringify({
+        effortLevel: "high",
+        modelSettings: { "claude-sonnet-5[1m]": { effortLevel: "high" } },
+      }),
+    );
+    const applyFlagSettings = vi.fn();
+    querySpy.mockReturnValue(
+      makeMockQuery({
+        initializationResult: async () => ({
+          models: [
+            {
+              value: "sonnet[1m]",
+              resolvedModel: "claude-sonnet-5[1m]",
+              displayName: "Sonnet",
+              description: "",
+              supportsEffort: true,
+              supportedEffortLevels: ["low", "medium", "high"],
+            },
+          ],
+        }),
+        applyFlagSettings,
+      }),
+    );
+    const { ClaudeAcpAgent } = await import("../acp-agent.js");
+    const agent = new ClaudeAcpAgent(createMockClient());
+    (agent as any).clientCapabilities = {
+      _meta: { jetbrains: { air: { version: 1, capabilities: ["recommendedValue"] } } },
+    };
+
+    const response = await (agent as any).createSession({
+      cwd: tempDir,
+      mcpServers: [],
+      _meta: {
+        disableBuiltInTools: true,
+        claudeCode: {
+          options: {
+            settings: {
+              effortLevel: "medium",
+              modelSettings: { "claude-sonnet-5-1m": { effortLevel: "low" } },
+            },
+          },
+        },
+      },
+    });
+
+    expect(response.configOptions.find((option: any) => option.id === "effort").currentValue).toBe(
+      "low",
+    );
+    expect(applyFlagSettings).toHaveBeenCalledWith({ effortLevel: "low" });
+    expect(agent.sessions[response.sessionId].effortSettingsOverride?.effortLevel).toBe("medium");
   });
 
   it("supports acceptEdits mode defaults", async () => {
@@ -150,6 +262,79 @@ describe("ClaudeAcpAgent settings", () => {
     expect(response.modes.currentModeId).toBe("default");
   });
 
+  it("honors the host opt-out from bypassPermissions", async () => {
+    await fs.promises.writeFile(
+      path.join(tempDir, "settings.json"),
+      JSON.stringify({ permissions: { defaultMode: "bypassPermissions" } }),
+    );
+    const projectDir = path.join(tempDir, "project");
+    await fs.promises.mkdir(projectDir, { recursive: true });
+
+    const { getCapturedOptions } = mockQuery();
+
+    const { ClaudeAcpAgent } = await import("../acp-agent.js");
+    const agent: ClaudeAcpAgentType = new ClaudeAcpAgent(createMockClient());
+    (agent as any).logger = { log: () => {}, error: () => {} };
+
+    const response = await (agent as any).createSession({
+      cwd: projectDir,
+      mcpServers: [],
+      _meta: {
+        disableBuiltInTools: true,
+        claudeCode: { options: { allowDangerouslySkipPermissions: false } },
+      },
+    });
+
+    expect(getCapturedOptions().allowDangerouslySkipPermissions).toBe(false);
+    expect(getCapturedOptions().permissionMode).toBe("default");
+    expect(response.modes.currentModeId).toBe("default");
+    expect(response.modes.availableModes.map((mode: { id: string }) => mode.id)).not.toContain(
+      "bypassPermissions",
+    );
+  });
+
+  it.each(["user", "project"] as const)(
+    "honors permissions.disableBypassPermissionsMode from %s settings",
+    async (tier) => {
+      const projectDir = path.join(tempDir, "project");
+      await fs.promises.mkdir(path.join(projectDir, ".claude"), { recursive: true });
+      await fs.promises.writeFile(
+        path.join(tempDir, "settings.json"),
+        JSON.stringify({
+          permissions: {
+            defaultMode: "bypassPermissions",
+            ...(tier === "user" ? { disableBypassPermissionsMode: "disable" } : {}),
+          },
+        }),
+      );
+      if (tier === "project") {
+        await fs.promises.writeFile(
+          path.join(projectDir, ".claude", "settings.json"),
+          JSON.stringify({ permissions: { disableBypassPermissionsMode: "disable" } }),
+        );
+      }
+
+      const { getCapturedOptions } = mockQuery();
+
+      const { ClaudeAcpAgent } = await import("../acp-agent.js");
+      const agent: ClaudeAcpAgentType = new ClaudeAcpAgent(createMockClient());
+      (agent as any).logger = { log: () => {}, error: () => {} };
+
+      const response = await (agent as any).createSession({
+        cwd: projectDir,
+        mcpServers: [],
+        _meta: { disableBuiltInTools: true },
+      });
+
+      expect(getCapturedOptions().allowDangerouslySkipPermissions).toBe(false);
+      expect(getCapturedOptions().permissionMode).toBe("default");
+      expect(response.modes.currentModeId).toBe("default");
+      expect(response.modes.availableModes.map((mode: { id: string }) => mode.id)).not.toContain(
+        "bypassPermissions",
+      );
+    },
+  );
+
   it("defaults to 'default' when no permissions.defaultMode is set", async () => {
     const projectDir = path.join(tempDir, "project");
     await fs.promises.mkdir(projectDir, { recursive: true });
@@ -253,7 +438,7 @@ describe("ClaudeAcpAgent settings", () => {
       };
     }
 
-    it("omits `auto` from availableModes when the resolved model lacks supportsAutoMode", async () => {
+    it("advertises `auto` when the resolved model lacks supportsAutoMode", async () => {
       const projectDir = path.join(tempDir, "project");
       await fs.promises.mkdir(projectDir, { recursive: true });
 
@@ -276,10 +461,8 @@ describe("ClaudeAcpAgent settings", () => {
       });
 
       const modeIds: string[] = response.modes.availableModes.map((m: any) => m.id);
-      expect(modeIds).not.toContain("auto");
-      expect(modeIds).toEqual(
-        expect.arrayContaining(["default", "acceptEdits", "plan", "dontAsk"]),
-      );
+      expect(modeIds).toEqual(expect.arrayContaining(["default", "acceptEdits", "plan", "auto"]));
+      expect(modeIds).not.toContain("dontAsk");
     });
 
     it("includes `auto` when the resolved model has supportsAutoMode: true", async () => {
@@ -305,10 +488,41 @@ describe("ClaudeAcpAgent settings", () => {
       });
 
       const modeIds: string[] = response.modes.availableModes.map((m: any) => m.id);
-      expect(modeIds).toContain("auto");
+      // A client that is not AIR gets no mode kind.
+      expect(response.modes.availableModes.slice(0, 4)).toEqual([
+        {
+          id: "default",
+          name: "Manual",
+          description: "Always ask before making changes",
+        },
+        {
+          id: "acceptEdits",
+          name: "Accept edits",
+          description: "Automatically accept all file edits",
+        },
+        {
+          id: "plan",
+          name: "Plan",
+          description: "Create a plan before making changes",
+        },
+        {
+          id: "auto",
+          name: "Auto",
+          description: "Claude handles permission decisions",
+        },
+      ]);
+      const bypass = response.modes.availableModes[4];
+      if (bypass) {
+        expect(bypass).toEqual({
+          id: "bypassPermissions",
+          name: "Bypass permissions",
+          description: "Accepts all permissions",
+        });
+      }
+      expect(modeIds).not.toContain("dontAsk");
     });
 
-    it("clamps permissions.defaultMode='auto' to 'default' on a model that lacks supportsAutoMode", async () => {
+    it("falls back permissions.defaultMode='auto' to Accept edits on an unsupported model", async () => {
       await fs.promises.writeFile(
         path.join(tempDir, "settings.json"),
         JSON.stringify({ permissions: { defaultMode: "auto" } }),
@@ -342,9 +556,11 @@ describe("ClaudeAcpAgent settings", () => {
         // carries the user-typed value; the SDK was synced via
         // setPermissionMode after we discovered the model can't honor it.
         expect(getCapturedOptions().permissionMode).toBe("auto");
-        expect(setPermissionModeSpy).toHaveBeenCalledWith("default");
-        expect(response.modes.currentModeId).toBe("default");
-        expect(response.modes.availableModes.map((m: any) => m.id)).not.toContain("auto");
+        expect(setPermissionModeSpy).toHaveBeenCalledWith("acceptEdits");
+        expect(response.modes.currentModeId).toBe("acceptEdits");
+        expect(response.modes.availableModes.map((m: any) => m.id)).toContain("auto");
+        const session = (agent as any).sessions[response.sessionId];
+        expect(session.autoModeFallbackWarningPending).toBe(true);
 
         // A descriptive warning was logged so operators see the clamp.
         const messages = errorSpy.mock.calls.map((c) => c.join(" "));

src/tests/acp-scenarios-compare.test.ts

@@ -0,0 +1,63 @@
+import { describe, expect, it } from "vitest";
+import { compareWithBaseline } from "./acp-scenarios/compare.js";
+import type { Recorded } from "./acp-scenarios/harness.js";
+
+function update(fields: Record<string, unknown>): Recorded {
+  return { kind: "sessionUpdate", payload: { sessionId: "s", update: fields } };
+}
+
+const toolCall = update({
+  sessionUpdate: "tool_call",
+  toolCallId: "t",
+  title: "Read",
+  status: "pending",
+  _meta: { claudeCode: { toolName: "Read" } },
+});
+
+const result = {
+  sessionUpdate: "tool_call_update",
+  toolCallId: "t",
+  title: "Read",
+  status: "completed",
+  rawOutput: "text",
+  _meta: { claudeCode: { toolName: "Read" } },
+};
+
+const baseline = [toolCall, update(result)];
+
+/** A copy of `value` without `key`. */
+function omit(value: Record<string, unknown>, key: string): Record<string, unknown> {
+  const copy = { ...value };
+  delete copy[key];
+  return copy;
+}
+
+describe("compareWithBaseline", () => {
+  it("accepts the baseline itself", () => {
+    expect(compareWithBaseline(baseline, baseline)).toEqual([]);
+  });
+
+  it("accepts an update without a field that did not change", () => {
+    expect(compareWithBaseline(baseline, [toolCall, update(omit(result, "title"))])).toEqual([]);
+  });
+
+  it("reports a dropped _meta key", () => {
+    expect(compareWithBaseline(baseline, [toolCall, update(omit(result, "_meta"))])).toContainEqual(
+      expect.stringMatching(/^origin\/main sent .*"toolName":"Read"/u),
+    );
+  });
+
+  it("reports a changed rawOutput", () => {
+    const changed = update({ ...result, rawOutput: "other" });
+    expect(compareWithBaseline(baseline, [toolCall, changed])).toContainEqual(
+      expect.stringMatching(/but the adapter sent .*"rawOutput":"other"/u),
+    );
+  });
+
+  it("reports an extra update", () => {
+    const extra = update({ sessionUpdate: "tool_call_update", toolCallId: "t", status: "failed" });
+    expect(compareWithBaseline(baseline, [...baseline, extra])).toEqual([
+      expect.stringMatching(/^origin\/main did not send /u),
+    ]);
+  });
+});

src/tests/acp-scenarios.test.ts

@@ -0,0 +1,986 @@
+/**
+ * The outbound ACP traffic of every scenario in `acp-scenarios/scenarios.ts`,
+ * for three client profiles: a plain ACP client, Zed, and JetBrains AIR.
+ *
+ * - Recordings are JSON Lines: one outbound message on each line, with sorted
+ *   keys. `normalize` in `harness.ts` replaces only exact run-specific values:
+ *   the generated ids, the paths, and the argv and version of this process.
+ * - AIR golden files: `acp-scenarios/__snapshots__/air/<scenario>.jsonl`.
+ *   Run `npx vitest run src/tests/acp-scenarios.test.ts -u` to update them.
+ * - Schema: every message is valid against the ACP schema of the SDK.
+ * - Plain and Zed: the same information as origin/main
+ *   (`acp-scenarios/origin-main/<profile>/<scenario>.jsonl`). `compare.ts`
+ *   allows only the documented differences. These profiles have no golden
+ *   files of their own. `origin-main/zed/` holds a scenario only when its
+ *   recording differs from the plain client.
+ * - Zed: the Zed conventions and the upstream `_meta` keys.
+ * - AIR: the AIR extensions of `docs/air-extensions.md`, each fact once.
+ *
+ * To record the origin/main baseline again, copy `src/tests/acp-scenarios/`
+ * and this file into a checkout of origin/main, and run this file there with
+ * `ACP_SCENARIO_BASELINE_DIR=<dir>`. Then copy `<dir>/plain` and `<dir>/zed`
+ * to `acp-scenarios/origin-main/`.
+ */
+import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
+import * as fs from "node:fs";
+import * as os from "node:os";
+import * as path from "node:path";
+import { fileURLToPath } from "node:url";
+import {
+  AIR_CAPABILITY_NAMES,
+  assistantTurn,
+  normalize,
+  PROFILES,
+  type Profile,
+  type Recorded,
+  resetIds,
+  result,
+  runScenario,
+  type Scenario,
+  type ScenarioRun,
+  streamMessage,
+  toolCall,
+  toolResult,
+} from "./acp-scenarios/harness.js";
+import { SCENARIOS } from "./acp-scenarios/scenarios.js";
+import {
+  AIR_ONLY_CLAUDE_CODE_KEYS,
+  AIR_ONLY_META_KEYS,
+  canonical,
+  compareWithBaseline,
+} from "./acp-scenarios/compare.js";
+import { EXTENSION_SESSION_UPDATES, validateRecorded } from "./acp-scenarios/schema.js";
+
+vi.mock("@anthropic-ai/claude-agent-sdk", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@anthropic-ai/claude-agent-sdk")>();
+  const harness = await import("./acp-scenarios/harness.js");
+  return {
+    ...actual,
+    query: harness.mockedQuery,
+    getSessionMessages: harness.mockedSessionMessages,
+  };
+});
+
+// The recordings replace only the ids that the run generated, so the harness
+// learns each id that `randomUUID` returns.
+vi.mock("node:crypto", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("node:crypto")>();
+  const harness = await import("./acp-scenarios/harness.js");
+  return {
+    ...actual,
+    randomUUID: (...args: Parameters<typeof actual.randomUUID>) => {
+      const id = actual.randomUUID(...args);
+      harness.noteGeneratedId(id);
+      return id;
+    },
+  };
+});
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const baselineDir = process.env.ACP_SCENARIO_BASELINE_DIR;
+const profiles = Object.values(PROFILES);
+const runs = new Map<string, ScenarioRun>();
+const key = (profile: Profile["name"], scenario: string) => `${profile}/${scenario}`;
+let configDir: string;
+let Agent: Parameters<typeof runScenario>[0];
+
+beforeAll(async () => {
+  // A run must not depend on the machine: no remote login, no Claude CLI, no
+  // user settings, and the bypass mode also for root.
+  for (const name of ["SSH_CONNECTION", "SSH_CLIENT", "SSH_TTY", "NO_BROWSER"]) {
+    vi.stubEnv(name, "");
+  }
+  vi.stubEnv("CLAUDE_CODE_REMOTE", "");
+  vi.stubEnv("ANTHROPIC_MODEL", "");
+  vi.stubEnv("IS_SANDBOX", "1");
+  vi.stubEnv("CLAUDE_CODE_EXECUTABLE", "/usr/bin/false");
+  configDir = fs.mkdtempSync(path.join(os.tmpdir(), "acp-scenario-config-"));
+  vi.stubEnv("CLAUDE_CONFIG_DIR", configDir);
+  const { ClaudeAcpAgent } = await import("../acp-agent.js");
+  Agent = ClaudeAcpAgent;
+  for (const profile of profiles) {
+    for (const scenario of SCENARIOS) {
+      resetIds();
+      runs.set(
+        key(profile.name, scenario.name),
+        await runScenario(ClaudeAcpAgent, profile, scenario),
+      );
+    }
+  }
+}, 120_000);
+
+afterAll(() => {
+  vi.unstubAllEnvs();
+  fs.rmSync(configDir, { recursive: true, force: true });
+});
+
+/** A recording as JSON Lines: one message on each line, with sorted keys. */
+function toJsonLines(recorded: Recorded[]): string {
+  return recorded.map((record) => `${canonical(record)}\n`).join("");
+}
+
+function fromJsonLines(text: string): Recorded[] {
+  return text
+    .split("\n")
+    .filter((line) => line.length > 0)
+    .map((line) => JSON.parse(line) as Recorded);
+}
+
+function run(profile: Profile["name"], scenario: string): ScenarioRun {
+  const recorded = runs.get(key(profile, scenario));
+  if (!recorded) throw new Error(`no run of ${scenario} for ${profile}`);
+  return recorded;
+}
+
+/** Runs one more scenario for AIR without some AIR capabilities. */
+async function runAir(scenario: Scenario, without: string[] = []): Promise<Recorded[]> {
+  resetIds();
+  const profile: Profile = {
+    name: "air",
+    capabilities: {
+      ...PROFILES.air.capabilities,
+      _meta: {
+        ...PROFILES.air.capabilities._meta,
+        jetbrains: {
+          air: {
+            version: 1,
+            capabilities: AIR_CAPABILITY_NAMES.filter((name) => !without.includes(name)),
+          },
+        },
+      },
+    },
+  };
+  return (await runScenario(Agent, profile, scenario)).raw;
+}
+
+function updates(recorded: Recorded[]): Record<string, any>[] {
+  return recorded
+    .filter((record) => record.kind === "sessionUpdate")
+    .map((record) => (record.payload as { update: Record<string, any> }).update);
+}
+
+function toolCallReports(recorded: Recorded[], toolCallId?: string): Record<string, any>[] {
+  return updates(recorded).filter(
+    (update) =>
+      (update.sessionUpdate === "tool_call" || update.sessionUpdate === "tool_call_update") &&
+      (toolCallId === undefined || update.toolCallId === toolCallId),
+  );
+}
+
+function permissionRequests(recorded: Recorded[]): Record<string, any>[] {
+  return recorded
+    .filter((record) => record.kind === "requestPermission")
+    .map((record) => record.payload as Record<string, any>);
+}
+
+/** Every `_meta` object in a message, with the path to it. */
+function metaObjects(value: unknown, at = "$"): { at: string; meta: Record<string, unknown> }[] {
+  if (!value || typeof value !== "object") return [];
+  if (Array.isArray(value)) return value.flatMap((item, i) => metaObjects(item, `${at}[${i}]`));
+  return Object.entries(value as Record<string, unknown>).flatMap(([k, item]) => [
+    ...(k === "_meta" && item && typeof item === "object" && !Array.isArray(item)
+      ? [{ at: `${at}._meta`, meta: item as Record<string, unknown> }]
+      : []),
+    ...metaObjects(item, `${at}.${k}`),
+  ]);
+}
+
+/** The origin/main recording of a scenario. Zed has a file only where it differs from the plain client. */
+function readBaseline(profile: "plain" | "zed", scenario: string): string {
+  const file = (name: string) =>
+    path.join(here, "acp-scenarios", "origin-main", name, `${scenario}.jsonl`);
+  return fs.readFileSync(
+    profile === "zed" && !fs.existsSync(file("zed")) ? file("plain") : file(profile),
+    "utf8",
+  );
+}
+
+describe.runIf(baselineDir)("the origin/main baseline", () => {
+  it("writes the recordings of the plain and Zed profiles", () => {
+    for (const profile of ["plain", "zed"] as const) {
+      fs.mkdirSync(path.join(baselineDir!, profile), { recursive: true });
+      for (const scenario of SCENARIOS) {
+        const text = toJsonLines(run(profile, scenario.name).normalized);
+        if (profile === "zed" && text === toJsonLines(run("plain", scenario.name).normalized)) {
+          continue;
+        }
+        fs.writeFileSync(path.join(baselineDir!, profile, `${scenario.name}.jsonl`), text);
+      }
+    }
+  });
+});
+
+describe.skipIf(baselineDir)("ACP scenarios", () => {
+  describe("normalize", () => {
+    const cwd = "/tmp/acp-scenario-x";
+    const session = "aaaaaaaa-0000-4000-8000-000000000001";
+    const first = "bbbbbbbb-0000-4000-8000-000000000002";
+    const second = "cccccccc-0000-4000-8000-000000000003";
+    const scripted = "00000000-0000-4000-8000-00000000c001";
+    const version = JSON.parse(
+      fs.readFileSync(path.join(here, "..", "..", "package.json"), "utf8"),
+    ).version;
+    const argv = process.argv.slice(1);
+
+    it("keeps a UUID that the run did not generate", () => {
+      expect(normalize({ toolCallId: scripted }, cwd, session, new Set([first]))).toEqual({
+        toolCallId: scripted,
+      });
+    });
+
+    it("names the generated ids in the order of their first appearance", () => {
+      const generated = new Set([first, second]);
+      const reports = (ids: string[]) =>
+        normalize(
+          ids.map((id) => ({ sessionId: session, toolCallId: id })),
+          cwd,
+          session,
+          generated,
+        );
+      expect(reports([first, first])).toEqual([
+        { sessionId: "<session>", toolCallId: "<id-1>" },
+        { sessionId: "<session>", toolCallId: "<id-1>" },
+      ]);
+      // A report that names another generated id, or the session id, still differs.
+      expect(reports([first, second])).not.toEqual(reports([first, first]));
+      expect(reports([first, session])).not.toEqual(reports([first, first]));
+    });
+
+    it("replaces only the exact argv prefix of this process", () => {
+      expect(argv.length).toBeGreaterThan(0);
+      expect(normalize({ args: [...argv, "--cli", "login"] }, cwd, session)).toEqual({
+        args: ["<argv>", "--cli", "login"],
+      });
+      // An extra argument stays in the recording, before or after the prefix.
+      expect(normalize({ args: [...argv, "--inspect", "--cli"] }, cwd, session)).toEqual({
+        args: ["<argv>", "--inspect", "--cli"],
+      });
+      const before = ["--inspect", ...argv, "--cli"];
+      const { args } = normalize({ args: before }, cwd, session) as { args: string[] };
+      expect(args).toHaveLength(before.length);
+      expect(args).not.toContain("<argv>");
+      expect(normalize({ args: ["other.js", "--cli"] }, cwd, session)).toEqual({
+        args: ["other.js", "--cli"],
+      });
+    });
+
+    it("replaces only the version of this adapter and the path of this Node binary", () => {
+      expect(normalize({ version, command: process.execPath }, cwd, session)).toEqual({
+        version: "<version>",
+        command: "<executable>",
+      });
+      expect(normalize({ version: "9.9.9", command: "/usr/bin/node" }, cwd, session)).toEqual({
+        version: "9.9.9",
+        command: "/usr/bin/node",
+      });
+    });
+
+    it("keeps durations and other numbers", () => {
+      expect(normalize({ durationMs: 7, totalDurationMs: 10 }, cwd, session)).toEqual({
+        durationMs: 7,
+        totalDurationMs: 10,
+      });
+    });
+  });
+
+  describe("schema check", () => {
+    const none = new Set<string>();
+    const elicitation = (url: string): Recorded => ({
+      kind: "createElicitation",
+      payload: {
+        sessionId: "s",
+        message: "Sign in",
+        mode: "url",
+        elicitationId: "e",
+        url,
+      },
+    });
+    const location = (line: number): Recorded => ({
+      kind: "sessionUpdate",
+      payload: {
+        sessionId: "s",
+        update: {
+          sessionUpdate: "tool_call_update",
+          toolCallId: "t",
+          locations: [{ path: "/a.ts", line }],
+        },
+      },
+    });
+
+    it("rejects a value that breaks a standard format", () => {
+      expect(validateRecorded(elicitation("https://example.com/login"), none)).toEqual([]);
+      expect(validateRecorded(elicitation("not a uri"), none)).not.toEqual([]);
+    });
+
+    it("rejects a value that breaks an ACP integer format", () => {
+      expect(validateRecorded(location(2 ** 32 - 1), none)).toEqual([]);
+      expect(validateRecorded(location(2 ** 32), none)).not.toEqual([]);
+    });
+  });
+
+  describe("air golden files", () => {
+    it.each(SCENARIOS.map((scenario) => scenario.name))("%s", async (scenario) => {
+      await expect(toJsonLines(run("air", scenario).normalized)).toMatchFileSnapshot(
+        path.join(here, "acp-scenarios", "__snapshots__", "air", `${scenario}.jsonl`),
+      );
+    });
+  });
+
+  describe.each(profiles.map((profile) => profile.name))("%s ACP schema", (profile) => {
+    const extensions = profile === "air" ? EXTENSION_SESSION_UPDATES : new Set<string>();
+    it.each(SCENARIOS.map((scenario) => scenario.name))(
+      "%s sends only valid messages",
+      (scenario) => {
+        const errors = run(profile, scenario).raw.flatMap((record) =>
+          validateRecorded(record, extensions),
+        );
+        expect(errors).toEqual([]);
+      },
+    );
+  });
+
+  describe.each(profiles.map((profile) => profile.name))("%s session ids", (profile) => {
+    // Only AIR negotiates native subagent sessions. There a child session
+    // gets updates after its parent announced it with `subagent_spawned`.
+    const nativeSubagents = profile === "air";
+    it.each(SCENARIOS.map((scenario) => scenario.name))(
+      "%s sends every session/update to the ACP session",
+      (scenario) => {
+        const { sessionId, raw } = run(profile, scenario);
+        const sessions = new Set([sessionId]);
+        const wrong: string[] = [];
+        for (const record of raw) {
+          if (record.kind !== "sessionUpdate") continue;
+          const payload = record.payload as { sessionId: string; update: Record<string, any> };
+          if (!sessions.has(payload.sessionId)) {
+            wrong.push(`${payload.sessionId}: ${payload.update.sessionUpdate}`);
+            continue;
+          }
+          if (nativeSubagents && payload.update.sessionUpdate === "subagent_spawned") {
+            sessions.add(payload.update.subagentSessionId);
+          }
+        }
+        expect(wrong).toEqual([]);
+      },
+    );
+  });
+
+  describe.each(["plain", "zed"] as const)("%s client", (profile) => {
+    it.each(SCENARIOS.map((scenario) => scenario.name))(
+      "%s carries the same information as origin/main",
+      (scenario) => {
+        const baseline = fromJsonLines(readBaseline(profile, scenario));
+        expect(compareWithBaseline(baseline, run(profile, scenario).normalized)).toEqual([]);
+      },
+    );
+
+    it.each(SCENARIOS.map((scenario) => scenario.name))(
+      "%s sends no key that exists only for AIR",
+      (scenario) => {
+        const found = metaObjects(run(profile, scenario).raw).flatMap(({ at, meta }) => [
+          ...Object.keys(meta)
+            .filter((k) => AIR_ONLY_META_KEYS.has(k))
+            .map((k) => `${at}.${k}`),
+          ...Object.keys((meta.claudeCode as Record<string, unknown> | undefined) ?? {})
+            .filter((k) => AIR_ONLY_CLAUDE_CODE_KEYS.has(k))
+            .map((k) => `${at}.claudeCode.${k}`),
+        ]);
+        expect(found).toEqual([]);
+        expect(
+          updates(run(profile, scenario).raw).filter((update) =>
+            EXTENSION_SESSION_UPDATES.has(update.sessionUpdate),
+          ),
+        ).toEqual([]);
+      },
+    );
+  });
+
+  describe("plain client", () => {
+    it("gets the Bash output as a code block and the description as content", () => {
+      const reports = toolCallReports(run("plain", "bash-foreground").raw, "toolu_bash");
+      expect(reports[0]).not.toHaveProperty("_meta.terminal_info");
+      expect(reports.some((r) => JSON.stringify(r.content ?? []).includes("List files"))).toBe(
+        true,
+      );
+      expect(reports.at(-2)).toMatchObject({
+        status: "completed",
+        content: [
+          { type: "content", content: { type: "text", text: "```console\na.ts\nb.ts\n```" } },
+        ],
+        rawOutput: "a.ts\nb.ts",
+      });
+    });
+
+    it("gets the streamed partial input as rawInput, and the Write text in rawInput", () => {
+      const reports = toolCallReports(run("plain", "write-new").raw, "toolu_write");
+      expect(reports[0]).toMatchObject({ sessionUpdate: "tool_call", rawInput: {} });
+      expect(reports.some((r) => r.rawInput?.file_path && !("content" in r.rawInput))).toBe(true);
+      expect(reports.some((r) => r.rawInput?.content === "export const x = 1;\n")).toBe(true);
+    });
+
+    it("gets the whole tool call again in a permission request", () => {
+      const [request] = permissionRequests(run("plain", "edit-with-permission").raw);
+      expect(request.toolCall).toMatchObject({
+        toolCallId: "toolu_edit",
+        name: "Edit",
+        status: "pending",
+        kind: "edit",
+        title: "Edit src/app.ts",
+        rawInput: {
+          old_string: "const value = 1;",
+          new_string: "const value = 2;",
+        },
+        content: [{ type: "diff", oldText: "const value = 1;", newText: "const value = 2;" }],
+      });
+      expect(request).not.toHaveProperty("_meta");
+    });
+
+    it("gets the question of a single AskUserQuestion as the title", () => {
+      const reports = toolCallReports(run("plain", "ask-user-question").raw, "toolu_ask");
+      expect(reports.map((r) => r.title)).toContain("Which database?");
+    });
+
+    it("gets the upstream NotebookEdit rendering and the result text", () => {
+      const reports = toolCallReports(run("plain", "notebook-edit").raw, "toolu_nb");
+      expect(reports[0]).toMatchObject({ title: "NotebookEdit", kind: "other", content: [] });
+      expect(reports.at(-1)).toMatchObject({
+        status: "completed",
+        rawOutput: "Updated cell cell-1 with print('hi')",
+      });
+    });
+
+    it("gets every Task* plan, also a repeated one", () => {
+      const plans = updates(run("plain", "task-create-update").raw).filter(
+        (update) => update.sessionUpdate === "plan",
+      );
+      expect(plans.map((plan) => plan.entries[0]?.status)).toEqual([
+        "pending",
+        "pending",
+        "in_progress",
+        "completed",
+        "completed",
+      ]);
+    });
+  });
+
+  describe("Zed", () => {
+    const zed = (scenario: string) => run("zed", scenario).raw;
+
+    it("keeps terminal_info, terminal_output, and terminal_exit", () => {
+      const reports = toolCallReports(zed("bash-foreground"), "toolu_bash");
+      expect(reports[0]).toMatchObject({
+        sessionUpdate: "tool_call",
+        content: [{ type: "terminal", terminalId: "toolu_bash" }],
+        _meta: { terminal_info: { terminal_id: "toolu_bash" } },
+      });
+      expect(reports).toContainEqual(
+        expect.objectContaining({
+          _meta: { terminal_output: { terminal_id: "toolu_bash", data: "a.ts\nb.ts" } },
+        }),
+      );
+      expect(reports).toContainEqual(
+        expect.objectContaining({
+          status: "completed",
+          _meta: expect.objectContaining({
+            terminal_exit: { terminal_id: "toolu_bash", exit_code: 0, signal: null },
+          }),
+        }),
+      );
+      for (const report of reports) {
+        expect(report._meta ?? {}).not.toHaveProperty("terminal_output_delta");
+      }
+    });
+
+    it("keeps the upstream claudeCode keys and the full PostToolUse toolResponse", () => {
+      const reports = toolCallReports(zed("bash-foreground"), "toolu_bash");
+      expect(reports[0]._meta.claudeCode).toEqual({ toolName: "Bash" });
+      expect(reports.at(-1)?._meta.claudeCode).toEqual({
+        toolName: "Bash",
+        toolResponse: { stdout: "a.ts\nb.ts", stderr: "", interrupted: false, isImage: false },
+      });
+      const child = toolCallReports(zed("subagent-task-legacy"), "toolu_sub_read");
+      expect(child[0]._meta.claudeCode).toEqual({
+        toolName: "Read",
+        parentToolUseId: "toolu_task",
+      });
+      // ACP does not merge `_meta` keys, so each update names the parent again.
+      for (const report of child) {
+        expect(report._meta.claudeCode).toMatchObject({
+          toolName: "Read",
+          parentToolUseId: "toolu_task",
+        });
+      }
+      const [childRequest] = permissionRequests(zed("subagent-task-legacy"));
+      expect(childRequest.toolCall._meta).toEqual({
+        claudeCode: { toolName: "Bash", parentToolUseId: "toolu_task" },
+      });
+      const [mcpRequest] = permissionRequests(zed("mcp-tool"));
+      expect(mcpRequest.toolCall._meta).toEqual({
+        claudeCode: {
+          toolName: "mcp__docs__search",
+          mcpServer: { name: "docs", source: "project" },
+        },
+      });
+    });
+
+    it("keeps the full permission denial toolResponse", () => {
+      const denial = toolCallReports(zed("permission-denied"), "toolu_denied").find(
+        (report) => report.status === "failed",
+      );
+      expect(denial?._meta.claudeCode.toolResponse).toEqual({
+        decisionReasonType: "rule",
+        decisionReason: "Denied by rule Bash(rm:*)",
+        message: "Permission to use Bash has been denied.",
+      });
+    });
+
+    it("keeps the _claude/* keys", () => {
+      const [elicitation] = zed("ask-user-question")
+        .filter((record) => record.kind === "createElicitation")
+        .map((record) => record.payload as Record<string, any>);
+      const options = elicitation.requestedSchema.properties.question_0.oneOf;
+      expect(options[0]._meta).toHaveProperty(["_claude/askUserQuestionOption"]);
+      const usage = updates(zed("rate-limit-and-origin")).filter(
+        (update) => update.sessionUpdate === "usage_update",
+      );
+      expect(usage.some((update) => update._meta?.["_claude/rateLimit"])).toBe(true);
+      expect(usage.some((update) => update._meta?.["_claude/origin"])).toBe(true);
+    });
+
+    it("keeps promptQueueing and steering", () => {
+      const initialize = zed("session-setup").find((record) => record.kind === "initialize")!
+        .payload as Record<string, any>;
+      expect(initialize.agentCapabilities._meta.claudeCode).toEqual({ promptQueueing: true });
+      expect(initialize._meta).toEqual({ steering: { supported: true } });
+    });
+
+    it("sends terminal-auth commands that rerun this adapter with --cli", () => {
+      // The raw traffic, because the recordings normalize the machine paths.
+      const initialize = zed("session-setup").find((record) => record.kind === "initialize")!
+        .payload as Record<string, any>;
+      const argv = process.argv.slice(1);
+      expect(initialize.authMethods).toEqual([
+        expect.objectContaining({
+          id: "claude-ai-login",
+          args: ["--cli", "auth", "login", "--claudeai"],
+          _meta: {
+            "terminal-auth": {
+              command: process.execPath,
+              args: [...argv, "--cli", "auth", "login", "--claudeai"],
+              label: "Claude Login",
+            },
+          },
+        }),
+        expect.objectContaining({
+          id: "console-login",
+          args: ["--cli", "auth", "login", "--console"],
+          _meta: {
+            "terminal-auth": {
+              command: process.execPath,
+              args: [...argv, "--cli", "auth", "login", "--console"],
+              label: "Anthropic Console Login",
+            },
+          },
+        }),
+      ]);
+    });
+  });
+
+  describe("AIR", () => {
+    const air = (scenario: string) => run("air", scenario).raw;
+    const airMeta = (meta: Record<string, any> | undefined) => meta?.jetbrains?.air;
+
+    it("gets the AIR capabilities and the goal capability under jetbrains.air", () => {
+      const initialize = air("session-setup").find((record) => record.kind === "initialize")!
+        .payload as Record<string, any>;
+      expect(initialize._meta).toEqual({
+        jetbrains: {
+          air: {
+            version: 1,
+            capabilities: expect.arrayContaining(
+              AIR_CAPABILITY_NAMES.filter((name) => name !== "rawInputRendering"),
+            ),
+            goal: expect.objectContaining({ version: 1 }),
+          },
+        },
+        steering: { supported: true },
+      });
+      const session = air("session-setup").find((record) => record.kind === "newSession")!
+        .payload as Record<string, any>;
+      for (const mode of session.modes.availableModes) {
+        expect(mode._meta).toEqual({
+          jetbrains: { air: { version: 1, kind: expect.any(String) } },
+        });
+      }
+    });
+
+    it("gets commandTitle, subagent, and skill under jetbrains.air, each once", async () => {
+      const bash = toolCallReports(air("bash-foreground"), "toolu_bash");
+      expect(bash.filter((r) => airMeta(r._meta)?.commandTitle === "List files")).toHaveLength(1);
+      // A native subagent session replaces the tool call of the subagent, so
+      // the marker shows without native subagent sessions.
+      const [nested] = toolCallReports(
+        await runAir(
+          {
+            name: "nested-agent",
+            turns: [
+              async function* () {
+                yield* assistantTurn("msg_nested", [
+                  { type: "tool_use", id: "toolu_nested", name: "Agent", input: { prompt: "Go" } },
+                ]);
+                yield result();
+              },
+            ],
+          },
+          ["nativeSubagentSessions"],
+        ),
+        "toolu_nested",
+      );
+      expect(airMeta(nested?._meta)?.subagent).toBe(true);
+      const skill = toolCallReports(air("skill"), "toolu_skill");
+      expect(skill.filter((r) => airMeta(r._meta)?.skill)).toEqual([
+        expect.objectContaining({
+          _meta: expect.objectContaining({
+            jetbrains: {
+              air: {
+                version: 1,
+                skill: { name: "commits", path: expect.stringMatching(/SKILL\.md$/) },
+              },
+            },
+          }),
+        }),
+      ]);
+    });
+
+    it("gets the permission, customAnswer, goal, and contextCompaction keys", () => {
+      const [request] = permissionRequests(air("bash-foreground"));
+      expect(request._meta).toEqual({
+        jetbrains: { air: { version: 1, permission: { version: 1, title: "ls -la" } } },
+      });
+      const elicitation = air("ask-user-question").find(
+        (record) => record.kind === "createElicitation",
+      )!.payload as Record<string, any>;
+      expect(elicitation.requestedSchema.properties.question_0_custom._meta).toEqual({
+        jetbrains: {
+          air: { version: 1, customAnswer: { questionId: "question_0", isCustomAnswer: true } },
+        },
+      });
+      const goal = updates(air("goal")).find((u) => u.sessionUpdate === "session_info_update");
+      expect(goal?._meta).toEqual({
+        jetbrains: {
+          air: {
+            version: 1,
+            goal: expect.objectContaining({ objective: "Ship the feature", status: "active" }),
+          },
+        },
+      });
+      const compaction = toolCallReports(air("compaction-legacy"));
+      expect(compaction.at(-1)?._meta).toEqual({
+        jetbrains: {
+          air: {
+            contextCompaction: expect.objectContaining({ version: 1, preTokens: 1000 }),
+          },
+        },
+      });
+      expect(compaction.at(-1)).not.toHaveProperty("rawOutput");
+    });
+
+    it("sends no upstream copy of an AIR key", () => {
+      for (const scenario of SCENARIOS) {
+        for (const { at, meta } of metaObjects(air(scenario.name))) {
+          const duplicates = [
+            ...Object.keys(meta).filter((k) => AIR_ONLY_META_KEYS.has(k) && k !== "jetbrains"),
+            ...Object.keys((meta.claudeCode as Record<string, unknown> | undefined) ?? {}).filter(
+              (k) => AIR_ONLY_CLAUDE_CODE_KEYS.has(k),
+            ),
+          ];
+          expect(duplicates, `${scenario.name} ${at}`).toEqual([]);
+        }
+      }
+    });
+
+    it("sends each tool fact in one field", () => {
+      for (const scenario of SCENARIOS) {
+        for (const report of toolCallReports(air(scenario.name))) {
+          const where = `${scenario.name} ${report.toolCallId}`;
+          // Output is never copied into rawOutput when content carries it.
+          if (report.rawOutput !== undefined) {
+            expect(report.content ?? [], where).toEqual([]);
+          }
+          // Terminal output goes to deltas, never to snapshots.
+          expect(report._meta ?? {}, where).not.toHaveProperty("terminal_output");
+        }
+      }
+      const write = toolCallReports(air("write-new"), "toolu_write");
+      for (const report of write) expect(report.rawInput ?? {}).not.toHaveProperty("content");
+      expect(write[0]).not.toHaveProperty("rawInput");
+    });
+
+    describe("ExitPlanMode with a plan file", () => {
+      const plan = "# Plan\n1. Do it";
+      /**
+       * The CLI streams the input that the model wrote, which has no plan.
+       * The complete message and canUseTool get the text and the path of the
+       * plan file. The structured result names the file again.
+       */
+      const planFileScenario = (options: { file: boolean; reject?: boolean }): Scenario => ({
+        name: "exit-plan-file",
+        ...(options.file ? { files: { "plans/plan.md": plan } } : {}),
+        ...(options.reject ? { permission: "reject_once" } : {}),
+        turns: [
+          async function* (ctx) {
+            const planFilePath = path.join(ctx.cwd, "plans", "plan.md");
+            const input = { plan, planFilePath };
+            yield* streamMessage("msg_toolu_plan", [
+              { type: "tool_use", id: "toolu_plan", name: "ExitPlanMode", input: {} },
+            ]);
+            yield* toolCall(
+              ctx,
+              { id: "toolu_plan", name: "ExitPlanMode", input },
+              options.reject
+                ? {
+                    ask: true,
+                    isError: true,
+                    content: "```\nThe user doesn't want to proceed with this tool use.\n```",
+                  }
+                : {
+                    ask: true,
+                    content: `User has approved your plan.\n\n## Approved Plan:\n${plan}`,
+                    structured: { plan, isAgent: false, filePath: planFilePath },
+                  },
+            );
+            yield result();
+          },
+        ],
+      });
+      it("sends the path and no plan text in every report", async () => {
+        const recorded = await runAir(planFileScenario({ file: true }));
+        const reports = toolCallReports(recorded, "toolu_plan");
+        const [request] = permissionRequests(recorded);
+        const withInput = [...reports, request.toolCall].filter((r) => "rawInput" in r);
+        expect(withInput.length).toBeGreaterThan(0);
+        for (const report of withInput) {
+          expect(report.rawInput).toEqual({ planFilePath: expect.stringMatching(/plan\.md$/) });
+          expect(path.isAbsolute(report.rawInput.planFilePath)).toBe(true);
+        }
+        expect(reports[0]).toMatchObject({ sessionUpdate: "tool_call" });
+        expect(reports[0]).not.toHaveProperty("rawInput");
+        expect(reports.at(-1)).toMatchObject({ status: "completed", title: "Exited Plan Mode" });
+        expect(JSON.stringify([reports, request])).not.toContain("Do it");
+      });
+
+      it("sends the path with a rejection", async () => {
+        const recorded = await runAir(planFileScenario({ file: true, reject: true }));
+        const reports = toolCallReports(recorded, "toolu_plan");
+        const [request] = permissionRequests(recorded);
+        expect(request.toolCall.rawInput).toEqual({ planFilePath: expect.any(String) });
+        expect(reports.at(-1)).toMatchObject({ status: "failed" });
+        expect(JSON.stringify([reports, request])).not.toContain("Do it");
+      });
+
+      it("sends the plan text when the plan file does not exist", async () => {
+        const recorded = await runAir(planFileScenario({ file: false }));
+        const [request] = permissionRequests(recorded);
+        expect(request.toolCall.rawInput).toEqual({ plan, planFilePath: expect.any(String) });
+      });
+
+      it("sends the plan text to an AIR client without planFile", async () => {
+        const recorded = await runAir(planFileScenario({ file: true }), ["planFile"]);
+        const [request] = permissionRequests(recorded);
+        expect(request.toolCall.rawInput).toEqual({ plan, planFilePath: expect.any(String) });
+      });
+
+      it("sends the whole input to a client that is not AIR", async () => {
+        for (const profile of [PROFILES.plain, PROFILES.zed]) {
+          resetIds();
+          const recorded = (await runScenario(Agent, profile, planFileScenario({ file: true })))
+            .raw;
+          const [request] = permissionRequests(recorded);
+          expect(request.toolCall.rawInput).toEqual({ plan, planFilePath: expect.any(String) });
+          expect(request.toolCall.content).toEqual([
+            { type: "content", content: { type: "text", text: plan } },
+          ]);
+          const reports = toolCallReports(recorded, "toolu_plan");
+          expect(reports.some((r) => r.rawInput?.plan === plan)).toBe(true);
+        }
+      });
+    });
+
+    it("drops every update of a tool call of a finished child session", () => {
+      const recorded = air("subagent-late-child-update");
+      const finished = recorded.findIndex(
+        (record) =>
+          record.kind === "sessionUpdate" &&
+          (record.payload as { update: Record<string, any> }).update.sessionUpdate ===
+            "subagent_state_update",
+      );
+      expect(finished).toBeGreaterThan(0);
+      const late = recorded
+        .slice(finished)
+        .filter((record) => record.kind === "sessionUpdate")
+        .map((record) => record.payload as { sessionId: string; update: Record<string, any> })
+        .filter(({ update }) => update.toolCallId === "toolu_late_read");
+      expect(late).toEqual([]);
+      for (const record of recorded.filter((r) => r.kind === "sessionUpdate")) {
+        const { sessionId, update } = record.payload as {
+          sessionId: string;
+          update: Record<string, any>;
+        };
+        if (update.toolCallId === "toolu_late_read") expect(sessionId).toBe("agent_late");
+      }
+    });
+
+    it("gets the Write patch, but no file text in the PostToolUse toolResponse", async () => {
+      const scenario = writtenFileScenario();
+      const hookReport = (recorded: Recorded[]) =>
+        toolCallReports(recorded, "toolu_write").find(
+          (report) =>
+            report._meta?.claudeCode?.toolResponse !== undefined || report.content?.[0]?._meta,
+        );
+      const airReport = hookReport(await runAir(scenario));
+      expect(airReport?.content?.[0]?._meta?.jetbrains?.air?.diffPatch?.text).toContain(
+        "-export const x = 0;\n+export const x = 1;\n",
+      );
+      expect(airReport?._meta?.claudeCode?.toolResponse).toBeUndefined();
+      expect(JSON.stringify(airReport)).not.toContain("originalFile");
+      // A client that is not AIR keeps the full toolResponse of origin/main.
+      resetIds();
+      const plain = (await runScenario(Agent, PROFILES.plain, scenario)).raw;
+      expect(hookReport(plain)?._meta?.claudeCode?.toolResponse).toMatchObject({
+        type: "update",
+        content: "export const x = 1;\n",
+        originalFile: "export const x = 0;\n",
+      });
+    });
+
+    it("sends no creation patch over a file and no Edit patch before the preview", async () => {
+      const patches = (reports: Record<string, any>[]) =>
+        reports.flatMap((report) =>
+          (report.content ?? [])
+            .map((block: any) => block._meta?.jetbrains?.air?.diffPatch?.text)
+            .filter((text: unknown) => text !== undefined),
+        );
+      // Streamed: the Write of an existing file gets only the update patch of
+      // its hook, and the Edit gets no patch before its approval.
+      const writePatches = patches(toolCallReports(air("write-existing"), "toolu_write"));
+      expect(writePatches).toHaveLength(1);
+      expect(writePatches[0]).not.toContain("new file mode");
+      expect(writePatches[0]).toContain("-export const x = 0;\n+export const x = 1;");
+      const edit = air("edit-with-permission");
+      const approval = edit.findIndex((record) => record.kind === "requestPermission");
+      expect(approval).toBeGreaterThan(0);
+      expect(patches(toolCallReports(edit.slice(0, approval), "toolu_edit"))).toEqual([]);
+      // Replayed: session/load renders the same tool uses from the transcript.
+      const replay = await runAir(replayedEditsScenario());
+      expect(patches(toolCallReports(replay))).toEqual([]);
+      // A replay does not read old.ts: the disk shows a later state than the history.
+      expect(toolCallReports(replay, "toolu_r_write")[0].content).toEqual([
+        {
+          type: "diff",
+          path: expect.stringMatching(/old\.ts$/),
+          oldText: null,
+          newText: "export const x = 1;\n",
+        },
+      ]);
+      expect(toolCallReports(replay, "toolu_r_edit")[0].content).toEqual([
+        {
+          type: "diff",
+          path: expect.stringMatching(/app\.ts$/),
+          oldText: "const value = 1;",
+          newText: "const value = 2;",
+        },
+      ]);
+    });
+
+    it("sends the Bash output as terminal deltas", () => {
+      const reports = toolCallReports(air("bash-foreground"), "toolu_bash");
+      expect(reports).toContainEqual(
+        expect.objectContaining({
+          _meta: { terminal_output_delta: { terminal_id: "toolu_bash", data: "a.ts\nb.ts" } },
+        }),
+      );
+    });
+  });
+});
+
+/** A Write that changes the file on disk before its PostToolUse hook runs. */
+function writtenFileScenario(): Scenario {
+  return {
+    name: "write-on-disk",
+    files: { "old.ts": "export const x = 0;\n" },
+    turns: [
+      async function* (ctx) {
+        const file = path.join(ctx.cwd, "old.ts");
+        const input = { file_path: file, content: "export const x = 1;\n" };
+        yield* assistantTurn("msg_write", [
+          { type: "tool_use", id: "toolu_write", name: "Write", input },
+        ]);
+        fs.writeFileSync(file, input.content);
+        yield toolResult("toolu_write", `The file ${file} has been updated successfully.`);
+        await ctx.postToolUse("toolu_write", "Write", input, {
+          type: "update",
+          filePath: file,
+          content: input.content,
+          structuredPatch: [
+            {
+              oldStart: 1,
+              oldLines: 1,
+              newStart: 1,
+              newLines: 1,
+              lines: ["-export const x = 0;", "+export const x = 1;"],
+            },
+          ],
+          originalFile: "export const x = 0;\n",
+        });
+        yield result();
+      },
+    ],
+  };
+}
+
+/** A session/load of a Write over an existing file and of an Edit. */
+function replayedEditsScenario(): Scenario {
+  return {
+    name: "replayed-edits",
+    files: { "old.ts": "export const x = 0;\n", "app.ts": "line 1\nconst value = 1;\n" },
+    transcript: ({ cwd, sessionId }) => [
+      {
+        type: "user",
+        uuid: "00000000-0000-4000-8000-00000000f001",
+        session_id: sessionId,
+        parent_tool_use_id: null,
+        message: { role: "user", content: "Change both files" },
+      },
+      {
+        type: "assistant",
+        uuid: "00000000-0000-4000-8000-00000000f002",
+        session_id: sessionId,
+        parent_tool_use_id: null,
+        message: {
+          id: "msg_r_edits",
+          role: "assistant",
+          model: "claude-sonnet-4-6",
+          content: [
+            {
+              type: "tool_use",
+              id: "toolu_r_write",
+              name: "Write",
+              input: { file_path: path.join(cwd, "old.ts"), content: "export const x = 1;\n" },
+            },
+            {
+              type: "tool_use",
+              id: "toolu_r_edit",
+              name: "Edit",
+              input: {
+                file_path: path.join(cwd, "app.ts"),
+                old_string: "const value = 1;",
+                new_string: "const value = 2;",
+              },
+            },
+          ],
+        },
+      },
+    ],
+    turns: [],
+  };
+}

src/tests/acp-scenarios/__snapshots__/air/ask-user-question.jsonl

@@ -0,0 +1,9 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"AskUserQuestion"}},"content":[],"kind":"other","name":"AskUserQuestion","sessionUpdate":"tool_call","status":"pending","title":"Asking for your input","toolCallId":"toolu_ask"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"questions":[{"header":"Database","multiSelect":false,"options":[{"description":"Relational","label":"Postgres","preview":"CREATE TABLE t ();"},{"description":"Key-value","label":"Redis"}],"question":"Which database?"}]},"sessionUpdate":"tool_call_update","toolCallId":"toolu_ask"}}}
+{"kind":"createElicitation","payload":{"message":"Which database?","mode":"form","requestedSchema":{"properties":{"question_0":{"oneOf":[{"_meta":{"_claude/askUserQuestionOption":{"preview":"CREATE TABLE t ();"}},"const":"Postgres","description":"Relational","title":"Postgres"},{"const":"Redis","description":"Key-value","title":"Redis"}],"title":"Database","type":"string"},"question_0_custom":{"_meta":{"jetbrains":{"air":{"customAnswer":{"isCustomAnswer":true,"questionId":"question_0"},"version":1}}},"description":"Type your own answer, or add a note to the option you chose above (optional).","title":"Other","type":"string"}},"type":"object"},"sessionId":"<session>","toolCallId":"toolu_ask"}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"User has answered your questions: \"Which database?\"=\"Postgres\".","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_ask"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/async-task-ends-before-tool-id.jsonl

@@ -0,0 +1,4 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"workflow_1","canStop":true,"description":"Build assets","name":"Build assets","outputFilePath":"/tmp/tasks/workflow_1.output","sessionUpdate":"async_task_spawned","showInTranscript":true,"taskType":"workflow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"workflow_1","sessionUpdate":"async_task_state_update","state":"completed","summary":"done"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/async-task-held-until-tool-id.jsonl

@@ -0,0 +1,5 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"monitor_1","canStop":true,"description":"Watch the logs","name":"Watch the logs","sessionUpdate":"async_task_spawned","showInTranscript":true,"taskType":"monitor","toolCallId":"toolu_monitor"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"monitor_1","sessionUpdate":"async_task_progress","summary":"first line","usage":{"durationMs":5,"toolUses":0,"totalTokens":0}}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"monitor_1","sessionUpdate":"async_task_progress","summary":"second line","usage":{"durationMs":6,"toolUses":0,"totalTokens":0}}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/async-task-released-at-turn-end.jsonl

@@ -0,0 +1,3 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"workflow_2","canStop":true,"description":"Build assets","name":"Build assets","sessionUpdate":"async_task_spawned","showInTranscript":true,"taskType":"workflow"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/bash-background.jsonl

@@ -0,0 +1,14 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_bg"}},"content":[{"terminalId":"toolu_bg","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"sleep 100","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"commandTitle":"Wait","version":1}}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"command":"sleep 100","description":"Wait","run_in_background":true},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"bash_1","canStop":true,"description":"sleep 100","name":"sleep 100","outputFilePath":"/tmp/tasks/bash_1.output","sessionUpdate":"async_task_spawned","showInTranscript":true,"taskType":"shell","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"asyncTasks":{"backgrounded":true}}},"terminal_output_delta":{"data":"Command running in background with ID: bash_1. Output is being written to: /tmp/tasks/bash_1.output. You will be notified when it completes.","terminal_id":"toolu_bg"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":0,"signal":null,"terminal_id":"toolu_bg"}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_bg"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"bash_1","sessionUpdate":"async_task_progress","summary":"still running","usage":{"durationMs":5,"toolUses":0,"totalTokens":0}}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"asyncTaskId":"bash_1","sessionUpdate":"async_task_state_update","state":"completed","summary":"done"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/bash-error.jsonl

@@ -0,0 +1,10 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_bash"}},"content":[{"terminalId":"toolu_bash","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"false","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"commandTitle":"Fail","version":1}}},"rawInput":{"command":"false","description":"Fail"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_output_delta":{"data":"Exit code 1\nboom","terminal_id":"toolu_bash"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":1,"signal":null,"terminal_id":"toolu_bash"}},"sessionUpdate":"tool_call_update","status":"failed","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/bash-foreground.jsonl

@@ -0,0 +1,14 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_bash"}},"content":[{"terminalId":"toolu_bash","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"ls -la","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"commandTitle":"List files","version":1}}},"rawInput":{"command":"ls -la","description":"List files"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bash"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"ls -la","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"rawInput":{"command":"ls -la","description":"List files"},"title":"ls -la","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_output_delta":{"data":"a.ts\nb.ts","terminal_id":"toolu_bash"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":0,"signal":null,"terminal_id":"toolu_bash"}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Do","type":"text"},"messageId":"msg_done","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"ne.","type":"text"},"messageId":"msg_done","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/compaction-failed-legacy.jsonl

@@ -0,0 +1,4 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"version":1},"version":1}}},"kind":"think","sessionUpdate":"tool_call","status":"in_progress","title":"Compact conversation","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"error":"Context too small","version":1}}}},"content":[{"content":{"text":"Compaction failed: Context too small","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"failed","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/compaction-legacy.jsonl

@@ -0,0 +1,7 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"version":1},"version":1}}},"kind":"think","sessionUpdate":"tool_call","status":"in_progress","title":"Compact conversation","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","status":"in_progress","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"durationMs":7,"postTokens":100,"preTokens":1000,"trigger":"automatic","version":1}}}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"usage_update","size":200000,"used":100}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":100}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/compaction-update.jsonl

@@ -0,0 +1,7 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"version":1},"version":1}}},"compactionId":"00000000-0000-4000-8000-000000000001","sessionUpdate":"compaction_update","status":"in_progress"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"compactionId":"00000000-0000-4000-8000-000000000001","content":{"text":"The summary.","type":"text"},"sessionUpdate":"compaction_summary_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"contextCompaction":{"durationMs":7,"postTokens":100,"preTokens":1000,"trigger":"automatic","version":1},"version":1}}},"compactionId":"00000000-0000-4000-8000-000000000001","sessionUpdate":"compaction_update","status":"completed"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"usage_update","size":200000,"used":100}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":100}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/edit-rejected.jsonl

@@ -0,0 +1,10 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Edit"}},"content":[],"kind":"edit","locations":[],"name":"Edit","sessionUpdate":"tool_call","status":"pending","title":"Edit","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"locations":[{"path":"<cwd>/src/app.ts"}],"sessionUpdate":"tool_call_update","title":"Edit src/app.ts","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"newText":"value = 2","oldText":"value = 1","path":"<cwd>/src/app.ts","type":"diff"}],"rawInput":{"file_path":"<cwd>/src/app.ts"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_edit"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Edit src/app.ts","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"content":[{"_meta":{"jetbrains":{"air":{"diffPatch":{"format":"git_patch","text":"diff --git a<cwd>/src/app.ts b<cwd>/src/app.ts\n--- a<cwd>/src/app.ts\n+++ b<cwd>/src/app.ts\n@@ -1 +1 @@\n-const value = 1;\n+const value = 2;\n","version":1},"version":1}}},"newText":"","oldText":null,"path":"<cwd>/src/app.ts","type":"diff"}],"rawInput":{"file_path":"<cwd>/src/app.ts"},"title":"Edit src/app.ts","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"```\nThe user doesn't want to proceed with this tool use. The tool use was rejected.\n```","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"failed","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/edit-with-permission.jsonl

@@ -0,0 +1,11 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Edit"}},"content":[],"kind":"edit","locations":[],"name":"Edit","sessionUpdate":"tool_call","status":"pending","title":"Edit","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"locations":[{"path":"<cwd>/src/app.ts"}],"sessionUpdate":"tool_call_update","title":"Edit src/app.ts","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"newText":"const value = 2;","oldText":"const value = 1;","path":"<cwd>/src/app.ts","type":"diff"}],"rawInput":{"file_path":"<cwd>/src/app.ts"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_edit"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Edit src/app.ts","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"content":[{"_meta":{"jetbrains":{"air":{"diffPatch":{"format":"git_patch","text":"diff --git a<cwd>/src/app.ts b<cwd>/src/app.ts\n--- a<cwd>/src/app.ts\n+++ b<cwd>/src/app.ts\n@@ -1,3 +1,3 @@\n line 1\n-const value = 1;\n+const value = 2;\n line 3\n","version":1},"version":1}}},"newText":"","oldText":null,"path":"<cwd>/src/app.ts","type":"diff"}],"rawInput":{"file_path":"<cwd>/src/app.ts"},"title":"Edit src/app.ts","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawOutput":"The file <cwd>/src/app.ts has been updated successfully.","sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"newText":"line 1\nconst value = 2;\nline 3","oldText":"line 1\nconst value = 1;\nline 3","path":"<cwd>/src/app.ts","type":"diff"}],"locations":[{"line":1,"path":"<cwd>/src/app.ts"}],"sessionUpdate":"tool_call_update","toolCallId":"toolu_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/exit-plan-approve.jsonl

@@ -0,0 +1,11 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"ExitPlanMode"}},"content":[],"kind":"switch_mode","name":"ExitPlanMode","sessionUpdate":"tool_call","status":"pending","title":"Approve Plan","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"plan":"# Plan\n1. Do it"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_plan"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Ready to code?","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes, manually approve edits","optionId":"exit-plan-default"},{"kind":"allow_always","name":"Yes, clear context (0% used) and use auto mode","optionId":"exit-plan-clear-auto"},{"kind":"allow_always","name":"Yes, and use auto mode","optionId":"exit-plan-auto"},{"kind":"allow_always","name":"Yes, and bypass permissions","optionId":"exit-plan-bypass"},{"kind":"reject_once","name":"No, keep planning","optionId":"reject"}],"sessionId":"<session>","toolCall":{"rawInput":{"plan":"# Plan\n1. Do it"},"title":"Approve Plan","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"currentModeId":"default","sessionUpdate":"current_mode_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"configOptions":[{"category":"mode","currentValue":"default","description":"Session permission mode","id":"mode","name":"Mode","options":[{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Always ask before making changes","name":"Manual","value":"default"},{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Automatically accept all file edits","name":"Accept edits","value":"acceptEdits"},{"_meta":{"jetbrains":{"air":{"kind":"plan","version":1}}},"description":"Create a plan before making changes","name":"Plan","value":"plan"},{"_meta":{"jetbrains":{"air":{"kind":"auto_review","version":1}}},"description":"Claude handles permission decisions","name":"Auto","value":"auto"},{"_meta":{"jetbrains":{"air":{"kind":"full_access","version":1}}},"description":"Accepts all permissions","name":"Bypass permissions","value":"bypassPermissions"}],"type":"select"},{"category":"model","currentValue":"claude-sonnet-4-6","description":"AI model to use","id":"model","name":"Model","options":[{"description":"Fast","name":"Claude Sonnet 4.6","value":"claude-sonnet-4-6"}],"type":"select"}],"sessionUpdate":"config_option_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","status":"completed","title":"Exited Plan Mode","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/exit-plan-reject.jsonl

@@ -0,0 +1,9 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"ExitPlanMode"}},"content":[],"kind":"switch_mode","name":"ExitPlanMode","sessionUpdate":"tool_call","status":"pending","title":"Approve Plan","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"plan":"# Plan\n1. Do it"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_plan"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Ready to code?","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes, manually approve edits","optionId":"exit-plan-default"},{"kind":"allow_always","name":"Yes, clear context (0% used) and use auto mode","optionId":"exit-plan-clear-auto"},{"kind":"allow_always","name":"Yes, and use auto mode","optionId":"exit-plan-auto"},{"kind":"allow_always","name":"Yes, and bypass permissions","optionId":"exit-plan-bypass"},{"kind":"reject_once","name":"No, keep planning","optionId":"reject"}],"sessionId":"<session>","toolCall":{"rawInput":{"plan":"# Plan\n1. Do it"},"title":"Approve Plan","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawOutput":"The user doesn't want to proceed with this tool use.","sessionUpdate":"tool_call_update","status":"failed","toolCallId":"toolu_plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/goal.jsonl

@@ -0,0 +1,3 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"goal":{"controlMethod":"_session/goal","objective":"Ship the feature","status":"active"},"version":1}}},"sessionUpdate":"session_info_update"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/grep-and-glob.jsonl

@@ -0,0 +1,14 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Grep"}},"content":[],"kind":"search","name":"Grep","sessionUpdate":"tool_call","status":"pending","title":"grep","toolCallId":"toolu_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"grep \"value\"","toolCallId":"toolu_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"grep \"value\" src","toolCallId":"toolu_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"-n":true,"output_mode":"content","path":"src","pattern":"value"},"sessionUpdate":"tool_call_update","title":"grep -n \"value\" src","toolCallId":"toolu_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Glob"}},"content":[],"kind":"search","locations":[],"name":"Glob","sessionUpdate":"tool_call","status":"pending","title":"Find","toolCallId":"toolu_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"pattern":"**/*.ts"},"sessionUpdate":"tool_call_update","title":"Find `**/*.ts`","toolCallId":"toolu_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"src/app.ts\nsrc/b.ts","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/mcp-tool.jsonl

@@ -0,0 +1,9 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"mcp__docs__search"},"is_mcp_tool_call":true},"content":[],"kind":"other","name":"mcp__docs__search","sessionUpdate":"tool_call","status":"pending","title":"mcp__docs__search","toolCallId":"toolu_mcp"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"q":"acp"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_mcp"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"mcp__docs__search","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"_meta":{"claudeCode":{"mcpServer":{"name":"docs","source":"project"}}},"rawInput":{"q":"acp"},"title":"mcp__docs__search","toolCallId":"toolu_mcp"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"Found 2 documents.","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_mcp"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/memory-recall.jsonl

@@ -0,0 +1,4 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"memory_recall","toolResponse":{"mode":"select"}}},"kind":"read","locations":[{"path":"/memory/a.md"},{"path":"/memory/b.md"}],"sessionUpdate":"tool_call","status":"completed","title":"Recalled 2 memories","toolCallId":"00000000-0000-4000-8000-000000000001"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"memory_recall","toolResponse":{"mode":"synthesize"}}},"content":[{"content":{"text":"The user prefers tabs.","type":"text"},"type":"content"}],"kind":"read","sessionUpdate":"tool_call","status":"completed","title":"Recalled synthesized memory","toolCallId":"00000000-0000-4000-8000-000000000002"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/network-permission.jsonl

@@ -0,0 +1,4 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"SandboxNetworkAccess"}},"content":[],"kind":"other","name":"SandboxNetworkAccess","rawInput":{"host":"example.com"},"sessionUpdate":"tool_call","status":"pending","title":"SandboxNetworkAccess","toolCallId":"toolu_net"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"description":"Reason: Sandbox blocks network","title":"example.com","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"rawInput":{"host":"example.com"},"title":"example.com","toolCallId":"toolu_net"}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/notebook-edit.jsonl

@@ -0,0 +1,11 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"NotebookEdit"}},"content":[],"kind":"edit","locations":[],"name":"NotebookEdit","sessionUpdate":"tool_call","status":"pending","title":"Edit notebook","toolCallId":"toolu_nb"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"locations":[{"path":"<cwd>/n.ipynb"}],"sessionUpdate":"tool_call_update","title":"Edit cell in n.ipynb","toolCallId":"toolu_nb"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","title":"Edit cell cell-1 in n.ipynb","toolCallId":"toolu_nb"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"cell_id":"cell-1","edit_mode":"replace","new_source":"print('hi')","notebook_path":"<cwd>/n.ipynb"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_nb"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Edit cell cell-1 in n.ipynb","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"<session>","toolCall":{"rawInput":{"cell_id":"cell-1","edit_mode":"replace","new_source":"print('hi')","notebook_path":"<cwd>/n.ipynb"},"title":"Edit cell cell-1 in n.ipynb","toolCallId":"toolu_nb"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_nb"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/permission-denied.jsonl

@@ -0,0 +1,10 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_denied"}},"content":[{"terminalId":"toolu_denied","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_denied"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"command":"rm -rf /"},"sessionUpdate":"tool_call_update","title":"rm -rf /","toolCallId":"toolu_denied"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolResponse":{"decisionReasonType":"rule","message":"Permission to use Bash has been denied."}}},"content":[{"content":{"text":"Permission denied: Denied by rule Bash(rm:*)","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"failed","toolCallId":"toolu_denied"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_output_delta":{"data":"Permission to use Bash has been denied.","terminal_id":"toolu_denied"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_denied"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":1,"signal":null,"terminal_id":"toolu_denied"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_denied"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/rate-limit-and-origin.jsonl

@@ -0,0 +1,8 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Work","type":"text"},"messageId":"msg_rate","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"ing.","type":"text"},"messageId":"msg_rate","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6","_claude/rateLimit":{"resetsAt":1700000000,"status":"allowed_warning","utilization":0.9}},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6","_claude/origin":{"kind":"human"}},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/read.jsonl

@@ -0,0 +1,8 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Read"}},"content":[],"kind":"read","locations":[],"name":"Read","sessionUpdate":"tool_call","status":"pending","title":"Read File","toolCallId":"toolu_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"locations":[{"line":1,"path":"<cwd>/a.ts"}],"rawInput":{"file_path":"<cwd>/a.ts"},"sessionUpdate":"tool_call_update","title":"Read a.ts","toolCallId":"toolu_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/session-load-replay.jsonl

@@ -0,0 +1,15 @@
+{"kind":"initialize","payload":{"_meta":{"jetbrains":{"air":{"capabilities":["sessionFailure","agentFileChangeReport","nativeSubagentSessions","asyncTasks","recommendedValue","diffPatch","planFile"],"goal":{"actions":["set","clear"],"controlMethod":"_session/goal","version":1},"version":1}},"steering":{"supported":true}},"agentCapabilities":{"_meta":{"authStatus":{},"claudeCode":{"promptQueueing":true}},"auth":{"logout":{}},"loadSession":true,"mcpCapabilities":{"http":true,"sse":true},"promptCapabilities":{"embeddedContext":true,"image":true},"providers":{},"sessionCapabilities":{"additionalDirectories":{},"close":{},"delete":{},"fork":{},"list":{},"resume":{},"subagents":{}}},"agentInfo":{"name":"@agentclientprotocol/claude-agent-acp","title":"Claude Agent","version":"<version>"},"authMethods":[],"protocolVersion":1}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Fix the bug","type":"text"},"messageId":"00000000-0000-4000-8000-00000000c001","sessionUpdate":"user_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Check the file.","type":"text"},"messageId":"msg_r1","sessionUpdate":"agent_thought_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"I will edit it.","type":"text"},"messageId":"msg_r1","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"jetbrains":{"air":{"commandTitle":"List","version":1}},"terminal_info":{"terminal_id":"toolu_r_bash"}},"content":[{"terminalId":"toolu_r_bash","type":"terminal"}],"kind":"execute","name":"Bash","rawInput":{"command":"ls","description":"List"},"sessionUpdate":"tool_call","status":"pending","title":"ls","toolCallId":"toolu_r_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Edit"}},"content":[{"newText":"b","oldText":"a","path":"<cwd>/src/app.ts","type":"diff"}],"kind":"edit","locations":[{"path":"<cwd>/src/app.ts"}],"name":"Edit","rawInput":{"file_path":"<cwd>/src/app.ts"},"sessionUpdate":"tool_call","status":"pending","title":"Edit src/app.ts","toolCallId":"toolu_r_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Explore","sessionUpdate":"subagent_spawned","subagentSessionId":"<session>:replay-subagent:toolu_r_task","task":"Look around"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_output_delta":{"data":"app.ts","terminal_id":"toolu_r_bash"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_r_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":0,"signal":null,"terminal_id":"toolu_r_bash"}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_r_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawOutput":"The file <cwd>/src/app.ts has been updated successfully.","sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_r_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>:replay-subagent:toolu_r_task","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_r_task"}},"content":{"text":"Subagent text.","type":"text"},"messageId":"msg_r_sub","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Fixed.","type":"text"},"messageId":"msg_r2","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"<session>:replay-subagent:toolu_r_task"}}}
+{"kind":"loadSession","payload":{"configOptions":[{"category":"mode","currentValue":"default","description":"Session permission mode","id":"mode","name":"Mode","options":[{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Always ask before making changes","name":"Manual","value":"default"},{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Automatically accept all file edits","name":"Accept edits","value":"acceptEdits"},{"_meta":{"jetbrains":{"air":{"kind":"plan","version":1}}},"description":"Create a plan before making changes","name":"Plan","value":"plan"},{"_meta":{"jetbrains":{"air":{"kind":"auto_review","version":1}}},"description":"Claude handles permission decisions","name":"Auto","value":"auto"},{"_meta":{"jetbrains":{"air":{"kind":"full_access","version":1}}},"description":"Accepts all permissions","name":"Bypass permissions","value":"bypassPermissions"}],"type":"select"},{"category":"model","currentValue":"claude-sonnet-4-6","description":"AI model to use","id":"model","name":"Model","options":[{"description":"Fast","name":"Claude Sonnet 4.6","value":"claude-sonnet-4-6"}],"type":"select"}],"modes":{"availableModes":[{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Always ask before making changes","id":"default","name":"Manual"},{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Automatically accept all file edits","id":"acceptEdits","name":"Accept edits"},{"_meta":{"jetbrains":{"air":{"kind":"plan","version":1}}},"description":"Create a plan before making changes","id":"plan","name":"Plan"},{"_meta":{"jetbrains":{"air":{"kind":"auto_review","version":1}}},"description":"Claude handles permission decisions","id":"auto","name":"Auto"},{"_meta":{"jetbrains":{"air":{"kind":"full_access","version":1}}},"description":"Accepts all permissions","id":"bypassPermissions","name":"Bypass permissions"}],"currentModeId":"default"},"sessionId":"<session>"}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}

src/tests/acp-scenarios/__snapshots__/air/session-setup.jsonl

@@ -0,0 +1,3 @@
+{"kind":"initialize","payload":{"_meta":{"jetbrains":{"air":{"capabilities":["sessionFailure","agentFileChangeReport","nativeSubagentSessions","asyncTasks","recommendedValue","diffPatch","planFile"],"goal":{"actions":["set","clear"],"controlMethod":"_session/goal","version":1},"version":1}},"steering":{"supported":true}},"agentCapabilities":{"_meta":{"authStatus":{},"claudeCode":{"promptQueueing":true}},"auth":{"logout":{}},"loadSession":true,"mcpCapabilities":{"http":true,"sse":true},"promptCapabilities":{"embeddedContext":true,"image":true},"providers":{},"sessionCapabilities":{"additionalDirectories":{},"close":{},"delete":{},"fork":{},"list":{},"resume":{},"subagents":{}}},"agentInfo":{"name":"@agentclientprotocol/claude-agent-acp","title":"Claude Agent","version":"<version>"},"authMethods":[],"protocolVersion":1}}
+{"kind":"newSession","payload":{"configOptions":[{"category":"mode","currentValue":"default","description":"Session permission mode","id":"mode","name":"Mode","options":[{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Always ask before making changes","name":"Manual","value":"default"},{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Automatically accept all file edits","name":"Accept edits","value":"acceptEdits"},{"_meta":{"jetbrains":{"air":{"kind":"plan","version":1}}},"description":"Create a plan before making changes","name":"Plan","value":"plan"},{"_meta":{"jetbrains":{"air":{"kind":"auto_review","version":1}}},"description":"Claude handles permission decisions","name":"Auto","value":"auto"},{"_meta":{"jetbrains":{"air":{"kind":"full_access","version":1}}},"description":"Accepts all permissions","name":"Bypass permissions","value":"bypassPermissions"}],"type":"select"},{"category":"model","currentValue":"claude-sonnet-4-6","description":"AI model to use","id":"model","name":"Model","options":[{"description":"Fast","name":"Claude Sonnet 4.6","value":"claude-sonnet-4-6"}],"type":"select"}],"modes":{"availableModes":[{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Always ask before making changes","id":"default","name":"Manual"},{"_meta":{"jetbrains":{"air":{"kind":"standard","version":1}}},"description":"Automatically accept all file edits","id":"acceptEdits","name":"Accept edits"},{"_meta":{"jetbrains":{"air":{"kind":"plan","version":1}}},"description":"Create a plan before making changes","id":"plan","name":"Plan"},{"_meta":{"jetbrains":{"air":{"kind":"auto_review","version":1}}},"description":"Claude handles permission decisions","id":"auto","name":"Auto"},{"_meta":{"jetbrains":{"air":{"kind":"full_access","version":1}}},"description":"Accepts all permissions","id":"bypassPermissions","name":"Bypass permissions"}],"currentModeId":"default"},"sessionId":"<session>"}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}

src/tests/acp-scenarios/__snapshots__/air/skill.jsonl

@@ -0,0 +1,8 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Skill"}},"content":[],"kind":"other","name":"Skill","sessionUpdate":"tool_call","status":"pending","title":"Load skill","toolCallId":"toolu_skill"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"jetbrains":{"air":{"skill":{"name":"commits","path":"<cwd>/.claude/skills/commits/SKILL.md"},"version":1}}},"rawInput":{"skill":"commits"},"sessionUpdate":"tool_call_update","title":"Load skill: commits","toolCallId":"toolu_skill"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawOutput":"Launching skill: commits","sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_skill"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-agent-async.jsonl

@@ -0,0 +1,10 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Agent","toolResponse":{"isAsync":true,"status":"async_launched"}}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_agent"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Background review","prompt":"Review the diff","sessionUpdate":"subagent_spawned","subagentSessionId":"a2","task":"Review the diff"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"a2","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_agent"}},"content":{"text":"Reviewi","type":"text"},"messageId":"msg_async_sub","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"a2","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_agent"}},"content":{"text":"ng now.","type":"text"},"messageId":"msg_async_sub","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"a2"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-late-child-update.jsonl

@@ -0,0 +1,9 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Check the logs","prompt":"Check logs","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_late","task":"Check logs"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_late","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_late","toolName":"Read"}},"content":[],"kind":"read","locations":[],"name":"Read","sessionUpdate":"tool_call","status":"pending","title":"Read File","toolCallId":"toolu_late_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_late","update":{"locations":[{"line":1,"path":"/var/log/app.log"}],"rawInput":{"file_path":"/var/log/app.log"},"sessionUpdate":"tool_call_update","title":"Read /var/log/app.log","toolCallId":"toolu_late_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"agent_late"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-native-sessions.jsonl

@@ -0,0 +1,19 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Fix the build","prompt":"Make the build pass","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_n","task":"Make the build pass"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_native"}},"content":{"text":"Running t","type":"text"},"messageId":"msg_native_sub_1","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_native"}},"content":{"text":"he build.","type":"text"},"messageId":"msg_native_sub_1","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_native","toolName":"Grep"}},"content":[],"kind":"search","name":"Grep","sessionUpdate":"tool_call","status":"pending","title":"grep","toolCallId":"toolu_native_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"sessionUpdate":"tool_call_update","title":"grep \"TODO\"","toolCallId":"toolu_native_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"rawInput":{"path":"/src","pattern":"TODO"},"sessionUpdate":"tool_call_update","title":"grep \"TODO\" /src","toolCallId":"toolu_native_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_native_grep"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_native","toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_native_bash"}},"content":[{"terminalId":"toolu_native_bash","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_native_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"sessionUpdate":"tool_call_update","title":"make","toolCallId":"toolu_native_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"jetbrains":{"air":{"commandTitle":"Build","version":1}}},"rawInput":{"command":"make","description":"Build"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_native_bash"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"make","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"agent_n","toolCall":{"rawInput":{"command":"make","description":"Build"},"title":"make","toolCallId":"toolu_native_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"terminal_output_delta":{"data":"make: *** Error 2","terminal_id":"toolu_native_bash"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_native_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_n","update":{"_meta":{"terminal_exit":{"exit_code":1,"signal":null,"terminal_id":"toolu_native_bash"}},"sessionUpdate":"tool_call_update","status":"failed","toolCallId":"toolu_native_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"failed","subagentSessionId":"agent_n"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-nested.jsonl

@@ -0,0 +1,14 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Plan the work","prompt":"Plan it","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_outer","task":"Plan it"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_outer","update":{"capabilities":{},"name":"Read the spec","prompt":"Read spec.md","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_inner","task":"Read spec.md"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_inner","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_inner","toolName":"Read"}},"content":[],"kind":"read","locations":[],"name":"Read","sessionUpdate":"tool_call","status":"pending","title":"Read File","toolCallId":"toolu_grandchild_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_inner","update":{"locations":[{"line":1,"path":"/spec.md"}],"rawInput":{"file_path":"/spec.md"},"sessionUpdate":"tool_call_update","title":"Read /spec.md","toolCallId":"toolu_grandchild_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_inner","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_grandchild_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_outer","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"agent_inner"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_outer","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_outer"}},"content":{"text":"Plan:","type":"text"},"messageId":"msg_outer_text","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_outer","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_outer"}},"content":{"text":" do X.","type":"text"},"messageId":"msg_outer_text","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"agent_outer"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-task-legacy.jsonl

@@ -0,0 +1,27 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Explore code","prompt":"Find the parser","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_1","task":"Find the parser"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task"}},"content":{"text":"Looking for","type":"text"},"messageId":"msg_sub_1","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task"}},"content":{"text":" the parser.","type":"text"},"messageId":"msg_sub_1","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task","toolName":"Read"}},"content":[],"kind":"read","locations":[],"name":"Read","sessionUpdate":"tool_call","status":"pending","title":"Read File","toolCallId":"toolu_sub_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"locations":[{"line":1,"path":"/x.ts"}],"rawInput":{"file_path":"/x.ts"},"sessionUpdate":"tool_call_update","title":"Read /x.ts","toolCallId":"toolu_sub_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_sub_read"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task","toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_sub_bash"}},"content":[{"terminalId":"toolu_sub_bash","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_sub_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"sessionUpdate":"tool_call_update","title":"rg parser","toolCallId":"toolu_sub_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"jetbrains":{"air":{"commandTitle":"Search","version":1}}},"rawInput":{"command":"rg parser","description":"Search"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_sub_bash"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"rg parser","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"agent_1","toolCall":{"rawInput":{"command":"rg parser","description":"Search"},"title":"rg parser","toolCallId":"toolu_sub_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"terminal_output_delta":{"data":"x.ts","terminal_id":"toolu_sub_bash"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_sub_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"terminal_exit":{"exit_code":0,"signal":null,"terminal_id":"toolu_sub_bash"}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_sub_bash"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task","toolName":"Edit"}},"content":[],"kind":"edit","locations":[],"name":"Edit","sessionUpdate":"tool_call","status":"pending","title":"Edit","toolCallId":"toolu_sub_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"locations":[{"path":"<cwd>/x.ts"}],"sessionUpdate":"tool_call_update","title":"Edit x.ts","toolCallId":"toolu_sub_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"content":[{"newText":"b","oldText":"a","path":"<cwd>/x.ts","type":"diff"}],"rawInput":{"file_path":"<cwd>/x.ts"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_sub_edit"}}}
+{"kind":"requestPermission","payload":{"_meta":{"jetbrains":{"air":{"permission":{"title":"Edit x.ts","version":1},"version":1}}},"options":[{"kind":"allow_once","name":"Yes","optionId":"allow-once"},{"kind":"reject_once","name":"No","optionId":"reject"}],"sessionId":"agent_1","toolCall":{"rawInput":{"file_path":"<cwd>/x.ts"},"title":"Edit x.ts","toolCallId":"toolu_sub_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"rawOutput":"The file has been updated.","sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_sub_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"locations":[{"line":1,"path":"<cwd>/x.ts"}],"sessionUpdate":"tool_call_update","toolCallId":"toolu_sub_edit"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task"}},"content":{"text":"Foun","type":"text"},"messageId":"msg_sub_2","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_1","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_task"}},"content":{"text":"d it.","type":"text"},"messageId":"msg_sub_2","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Task","toolResponse":{"status":"completed"}}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_task"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"agent_1"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/subagent-transcript-extension.jsonl

@@ -0,0 +1,14 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"capabilities":{},"name":"Summarize","prompt":"Summarize the repo","sessionUpdate":"subagent_spawned","subagentSessionId":"agent_t","task":"Summarize the repo"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_transcript"}},"content":{"text":"Look at t","type":"text"},"messageId":"msg_transcript_sub","sessionUpdate":"agent_thought_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_transcript"}},"content":{"text":"he layout.","type":"text"},"messageId":"msg_transcript_sub","sessionUpdate":"agent_thought_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_transcript"}},"content":{"text":"The repo has ","type":"text"},"messageId":"msg_transcript_sub","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_transcript"}},"content":{"text":"two packages.","type":"text"},"messageId":"msg_transcript_sub","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"_meta":{"claudeCode":{"parentToolUseId":"toolu_transcript","toolName":"Glob"}},"content":[],"kind":"search","locations":[],"name":"Glob","sessionUpdate":"tool_call","status":"pending","title":"Find","toolCallId":"toolu_transcript_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"rawInput":{"pattern":"*"},"sessionUpdate":"tool_call_update","title":"Find `*`","toolCallId":"toolu_transcript_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"agent_t","update":{"content":[{"content":{"text":"a\nb","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_transcript_glob"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"sessionUpdate":"subagent_state_update","state":"completed","subagentSessionId":"agent_t"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/task-create-update.jsonl

@@ -0,0 +1,16 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"entries":[{"content":"Write tests","priority":"medium","status":"pending"}],"sessionUpdate":"plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"entries":[{"content":"Write tests","priority":"medium","status":"in_progress"}],"sessionUpdate":"plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"entries":[{"content":"Write tests","priority":"medium","status":"completed"}],"sessionUpdate":"plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"All ","type":"text"},"messageId":"msg_follow","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"done.","type":"text"},"messageId":"msg_follow","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/task-output-and-stop.jsonl

@@ -0,0 +1,12 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"TaskOutput"}},"content":[],"kind":"other","name":"TaskOutput","sessionUpdate":"tool_call","status":"pending","title":"TaskOutput","toolCallId":"toolu_out"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"block":true,"task_id":"bash_1"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_out"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"<retrieval_status>success</retrieval_status>\n<output>done</output>","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_out"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"TaskStop"}},"content":[],"kind":"other","name":"TaskStop","sessionUpdate":"tool_call","status":"pending","title":"TaskStop","toolCallId":"toolu_stop"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"task_id":"bash_1"},"sessionUpdate":"tool_call_update","toolCallId":"toolu_stop"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":[{"content":{"text":"Successfully stopped task: bash_1","type":"text"},"type":"content"}],"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_stop"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/text-and-thinking.jsonl

@@ -0,0 +1,9 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Let me thin","type":"text"},"messageId":"msg_text","sessionUpdate":"agent_thought_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"k about it.","type":"text"},"messageId":"msg_text","sessionUpdate":"agent_thought_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"Here is t","type":"text"},"messageId":"msg_text","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"content":{"text":"he answer.","type":"text"},"messageId":"msg_text","sessionUpdate":"agent_message_chunk"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/todo-write.jsonl

@@ -0,0 +1,6 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"entries":[{"content":"Writing tests","priority":"medium","status":"in_progress"},{"content":"Ship","priority":"medium","status":"pending"}],"sessionUpdate":"plan"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}

src/tests/acp-scenarios/__snapshots__/air/tool-progress.jsonl

@@ -0,0 +1,12 @@
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"availableCommands":[],"sessionUpdate":"available_commands_update"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolName":"Bash"},"terminal_info":{"terminal_id":"toolu_slow"}},"content":[{"terminalId":"toolu_slow","type":"terminal"}],"kind":"execute","name":"Bash","sessionUpdate":"tool_call","status":"pending","title":"Terminal","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"sessionUpdate":"usage_update","size":200000,"used":3}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"rawInput":{"command":"make"},"sessionUpdate":"tool_call_update","title":"make","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolResponse":{"elapsedTimeSeconds":1}}},"sessionUpdate":"tool_call_update","status":"in_progress","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolResponse":{"elapsedTimeSeconds":2}}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"claudeCode":{"toolResponse":{"elapsedTimeSeconds":3}}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_output_delta":{"data":"built","terminal_id":"toolu_slow"}},"sessionUpdate":"tool_call_update","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"terminal_exit":{"exit_code":0,"signal":null,"terminal_id":"toolu_slow"}},"sessionUpdate":"tool_call_update","status":"completed","toolCallId":"toolu_slow"}}}
+{"kind":"sessionUpdate","payload":{"sessionId":"<session>","update":{"_meta":{"_claude/model":"claude-sonnet-4-6"},"cost":{"amount":0,"currency":"USD"},"sessionUpdate":"usage_update","size":200000,"used":2}}}
+{"kind":"promptResponse","payload":{"_meta":{"quota":{"model_usage":[],"token_count":{"cachedInputTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"reasoningOutputTokens":0,"totalTokens":0}}},"stopReason":"end_turn","usage":{"cachedReadTokens":0,"cachedWriteTokens":0,"inputTokens":0,"outputTokens":0,"totalTokens":0}}}