9392c69cc6
Fixes #1114. ## Problem A steered turn settles only at an SDK `idle`, and only once the steer's echo has been replayed and an outcome recorded. Two ways that never happens, both from #1114: - **Missing echo.** If the CLI never replays the steered message, every idle is swallowed and `session/prompt` parks until cancel or the next prompt. - **Owed-idle debt eats the settling idle.** If the steer aborts an autonomous followup, that followup's result counts a trailing idle, but the abort folds it into the one idle that spans both cycles. The debt lane absorbs that idle and the steered turn never settles. ## Fix 1. **Exact lane: settle on the result that answers the steer.** A result whose `user_message_uuids` (falling back to `user_message_uuid`) names one of the turn's steers retires that steer's echo, even if the CLI never replayed it. Once no steer is outstanding, the turn leaves the steer lane and settles at that result through the ordinary lanes, including the subagent hold and failure lanes. It owes its trailing idle like any other settling result. No timer. 2. **Idle fallback, for producers that don't stamp results: count only a result recorded after the last echo.** Before this, the outcome of the cycle the steer interrupted (or a held turn's outcome that `steer()` moved over) made the turn look ready as soon as the echo landed. `steeredAwaitingResult` is set when an echo drains and cleared when a result is recorded. 3. **A ready steered turn takes the idle ahead of owed-idle debt.** Its outcome is final, so whichever idle arrives settles it correctly. The debt is left standing: a separate trailing idle still absorbs the idle it belongs to, and one that never comes is cleared by the existing sweep at the next `running` transition. A steered turn that isn't ready still goes through the debt lane first, so an earlier turn's late idle can never settle a steered cycle that's still running. ## Live verification (CLI 2.1.280, SDK 0.3.280) A probe with the adapter's query options (`replay-user-messages`, partial messages) steered a running turn three ways: mid-generation at `now`, mid-tool-call at `now`, and mid-tool-call at `later`. All three had the same frame order: ``` RESULT stamp=ORIG stamps=[ORIG] <- interrupted (or finished) original cycle lifecycle ORIG cancelled|completed lifecycle STEER started ECHO STEER RESULT stamp=STEER stamps=[STEER] <- steered cycle lifecycle STEER completed STATE idle <- the only idle ``` So the interrupted cycle's result never names the steer, and the steered cycle's result always does. `later` doesn't fold the steer into the running turn either; it runs as its own cycle after the original finishes, with no idle in between. ## Tests Three new tests in `turn steering (_session/steering)`: - **Echo missing, stamped result:** the turn settles at the result before any idle, and the idle that follows is absorbed. Hangs on `main`. - **Steer aborts an autonomous followup, only one idle:** the turn settles. Hangs on `main`. - **Owed idle arrives after the echo but before the steered result:** the turn must not settle on it, and it ends with both cycles' usage. Passes on `main`, but fails with the post-echo readiness check removed, so it guards against settling early on a pre-steer outcome. `npm run build`, `npm run test:run` and `npm run check` pass. ## Remaining gap If the echo never replays and the result carries no stamp (older producers), the turn still waits for cancel or the next prompt, as documented before. Supersedes #1115 and #1063. Thanks to @KlausUllrich for the #1114 analysis and the result-acknowledgement idea, which this builds on. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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)
- Following
- Edit review
- TODO lists
- Nested subagent transcripts
- Interactive (and background) terminals
- Custom Slash commands
- Client MCP servers
- Session-scoped long-running goals through the provider-neutral goal extension
- 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
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
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.
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).