ddee24ef8f
## Summary
Updates `@anthropic-ai/claude-agent-sdk` from 0.3.322 to 0.3.323, which
bundles Claude Code 2.1.323. The new version needs two adapter fixes,
both included here:
- the session index reads titles by the SDK's new rule;
- the heartbeat of a long-running hook no longer lands on a tool call.
Also bumps these dev dependencies: `@anthropic-ai/sdk` 1.7.0 → 1.8.0,
`@tsconfig/node22` 22.0.6 → 22.0.7 and `prettier` 3.9.10 → 3.10.1.
`npm update` brings the in-range lockfile bumps: `rolldown` 1.2.18 →
1.2.19, `vite` 8.3.7 → 8.3.8, `hono` 4.13.17 → 4.13.18,
`@hono/node-server` 2.1.6 → 2.1.8, and patch releases of
`@babel/runtime`, `brace-expansion`, `encodeurl`,
`@jridgewell/resolve-uri` and `@rolldown/pluginutils`. `rolldown` 1.2.19
lists its wasm32 binding as an optional dependency, so the lockfile
gains `@rolldown/binding-wasm32-wasi`, `@napi-rs/wasm-runtime`,
`@emnapi/core` and `@emnapi/runtime` (2.0.0-beta.2),
`@emnapi/wasi-threads`, `@tybys/wasm-util` and `tslib`. All are dev-only
and optional.
TypeScript stays at 6.0.3: 7.0.2 is out, but `@typescript-eslint/parser`
8.72.2 still requires `typescript <6.1.0`.
## Session titles
`getSessionInfo` and `listSessions` of SDK 0.3.323 read titles
differently, and neither changelog says so. The session index mirrors
the SDK's rule (`sdkTitles` in `src/session-index/transcript-scan.ts`),
so it has to follow.
- Before: the SDK took the last `"customTitle":"…"` text of the tail or
the head, wherever it stood.
- Now: it parses each line that names the field, from the last one back,
and takes the top-level string of the record. For `customTitle` and
`aiTitle` the record must be of type `custom-title` or `ai-title`.
`lastPrompt` and `summary` may be on a record of any type.
What changes for a client:
- A `customTitle` or `lastPrompt` inside a message is no title. A tool
result that shows a transcript no longer renames the session.
- A `custom-title` record that the start of the 64 KB tail window cuts
is not read. The old rule still found its title text.
- A `custom-title` record appended to a line whose write was cut off is
read.
Checked against the real SDK: a differential run of `sdkTitles` against
`getSessionInfo` over 1,800 generated transcripts gave no mismatch. The
old rule mismatched on 371 of 600. The run is not part of this PR; the
tests in `src/tests/v1/session-index.test.ts` compare each case above
with `getSessionInfo`.
## Hook heartbeats
Since Claude Code 2.1.323, a hook that runs long sends a `tool_progress`
beat every 30 seconds. Recorded from the real CLI:
```json
{
"type": "tool_progress",
"tool_use_id": "hook-PreToolUse-toolu_01X…-heartbeat-0",
"tool_name": "PreToolUse",
"parent_tool_use_id": "toolu_01X…",
"elapsed_time_seconds": 30,
"heartbeat": true
}
```
For a PreToolUse or PostToolUse hook, `parent_tool_use_id` is the tool
call. For a UserPromptSubmit or Stop hook it is an id that names no tool
call. The PostToolUse beats come before the tool result.
Both cores send a beat under an unknown id to the call that
`parent_tool_use_id` names. So without a change, a slow PreToolUse or
PostToolUse hook:
- marked the tool call `in_progress` before it ran, on v1 and v2;
- restarted its elapsed time with the hook's (30 → 1 → 2 → 3 → 30 in the
scenario);
- named the call `PreToolUse` in `_meta.claudeCode.toolName` for a plain
or Zed client.
The adapter now drops these beats. This matches how it already ignores
`hook_started`, `hook_progress` and `hook_response`: hooks have no ACP
surface. The rule that picks the tool call of a beat was written twice,
in `src/v1/acp-agent.ts` and `src/v2/stream.ts`. It is now one function,
`progressToolCallId` in `src/tool-calls/renderer.ts`, which holds the
new rule too.
The `tool-progress` scenario carries a PreToolUse and a PostToolUse
beat. Its recordings for the plain, Zed, AIR and v2 clients are
unchanged, and all four fail without the fix.
## Changelog review
Read the SDK changelog for 0.3.323 and the Claude Code changelog for
2.1.323. No other entry needs a code change:
- **Types.** Doc text and new optional members only, plus one new
`SDKStartupFailureReason` (`managed_settings_not_delivered`).
`startupFailureError` treats a reason it does not list as an internal
error with the CLI's message.
- **Context window of an unknown model id**, 200K → 1M. The adapter
reads the window from Claude Code (`getContextUsage`) at session
creation and at every model switch, so it reports the new value. Its own
200K is only the placeholder until that read lands.
- **`canUseTool` suggestions** no longer hold a Bash allow rule for a
write to `.git` or `.claude`. The adapter then offers no "always allow"
option.
- **`init.plugin_errors`** also lists load errors of plugins that
managed settings enable. The adapter only logs them.
- **`forkSession` with `upToMessageId`** and **`getSessionMessages`**
compaction fixes. Picked up as they are: the adapter has no workaround
for the old behavior.
- **A subagent's WebSearch result can carry `tool_use_result`.** The
code reads only fields that this result does not have. One comment in
`src/async-tasks.ts` said that no subagent result carries one; it now
says Bash results.
- **A permission check that fails after a PreToolUse hook allowed the
call** goes to `canUseTool`, which the adapter always provides.
## Not in this PR
Left for follow-ups, because each is its own change:
- The 200K placeholder for the context window. 1M is now the more likely
value, and with it the "1m" text heuristic has nothing left to do.
- `matchDeniedModels()` (alpha). The adapter's own `isDeniedModel`
disagrees with it on 23 of 875 model and entry pairs.
- `supersedes` on the retry of a response whose tool call could not be
parsed. The adapter does not act on `supersedes`.
- `machinePolicy.didNotLoad` (alpha) of `resolveSettings()`.
## Testing
- `npm run build`, `npm run check`, `npm run test:run` (4,121 tests
pass)
- Real CLI: one short session with slow hooks and
`CLAUDE_CODE_HOOK_HEARTBEAT_INTERVAL_MS=1000`, to record the heartbeat
frames and their order
- Real CLI: `getContextUsage` for unknown and known model ids, without a
prompt
ACP adapter for the Claude Agent SDK
Use Claude Agent SDK from ACP-compatible clients!
This tool implements an ACP agent by using the official Claude Agent SDK, supporting:
- Context @-mentions
- Images
- Tool calls (with permission requests)
- Compact file changes through the negotiated AIR diff patch extension
- Following
- Edit review
- TODO lists
- Nested subagent transcripts
- Interactive (and background) terminals
- Custom Slash commands
- Client MCP servers
- An Ultracode session config option, which turns on Claude Code's dynamic workflows for every task. It appears when dynamic workflows are enabled and the model supports ultracode (any model with
xhigheffort) /mcpin the chat: the MCP server status as a list. The adapter runs/mcp reconnect,/mcp enable, and/mcp disablethrough the SDK control API, because Claude Code refuses them in SDK mode. A reconnect of an ACP server that needs authentication starts MCP OAuth through URL elicitation- Session-scoped long-running goals for AIR through the goal extension under
_meta.jetbrains.air.goal - Structured errors, recovery, and warnings through the opt-in session failure extension
- Concrete model and effort defaults through the opt-in recommended config value extension
- Tool permission presentation, editable choices, and durable effects through the permission extension
- One fact per field in every tool call report, as the ACP tool call contract defines
- All AIR extensions, capabilities, and
_metakeys: AIR extensions
Learn more about the Agent Client Protocol.
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.
npm install @agentclientprotocol/claude-agent-acp@preview
Standalone executables
Each release attaches archives for Linux (glibc and musl), macOS and Windows, on
x64 and arm64, to its GitHub release.
They need no Node.js install. Each holds two files: claude-agent-acp, and the
Claude CLI (claude) it runs. Keep them in the same directory; a symlink to
claude-agent-acp elsewhere works. To use a Claude CLI you already have
instead, set CLAUDE_CODE_EXECUTABLE. On Alpine, install libgcc and
libstdc++ first.
To build one for your machine (needs Bun) and check it:
npm run build:binary
npm run smoke:binary # add `-- --full` to drive a real session; needs a Claude login
Experimental ACP v2
The adapter also serves the draft ACP v2:
a client that asks for protocol version 2 or later in initialize gets v2, and every other client
gets v1. The draft can still change, and this surface changes with it.
CLAUDE_AGENT_ACP_PROTOCOL limits the adapter to one version. With v1, a client that asks
for v2 is negotiated down to v1. With v2, the adapter rejects the initialize of a v1 client.
auto, the default, serves both.
On v2 the adapter serves the session baseline (session/new, session/list, session/resume
with replay, session/close, session/prompt, session/cancel), session/delete,
session/fork, session/status, session/options (with initial configOptions on session/new and
session/resume), session/set_title, additional directories, config options (the mode is one), plans, notices,
compaction, display terminals for commands, permission requests, elicitation, providers, auth, and
subagents. Steering is v1 only for now.
v2 is served by the v2 agent in src/v2/, which runs straight on Claude
Code instead of translating to v1. A v2 client that declares JetBrains AIR
(_meta.jetbrains.air) also gets the AIR extensions that ACP v2 does not cover.
Contribution Policy
This project does not require a Contributor License Agreement (CLA). Instead, contributions are accepted under the following terms:
By contributing to this project, you agree that your contributions will be licensed under the Apache License, Version 2.0. You affirm that you have the legal right to submit your work, that you are not including code you do not have rights to, and that you understand contributions are made without requiring a Contributor License Agreement (CLA).