b1d6cfc6c9
Found while reviewing the ACP v2 prompt lifecycle (#1226). It affects ACP v1 and v2. ## Problem `session/close` tears the session down: `teardownSession` cancels its turns, wakes the consumer, and closes the query. It returned without waiting for the cancelled turns to end, so the close could answer first: - **v1:** the `session/prompt` response arrived after the `session/close` response. - **v2:** the turn's `idle cancelled` arrived after the close response. v2's `session/close` cancels "as if `session/cancel` had been called", then frees the session. It happens when the consumer settles the turn late: for example, while it's still sending an update to a slow client, or when it settles the turn only at the end of the stream that the close ends. ## Change `teardownSession` now returns once the turns it cancels have ended (each turn's `completion`), for at most `TEARDOWN_TURN_END_TIMEOUT_MS` (5 s), which it logs if a wedged consumer hits it. Its other callers get the same order too: `session/delete`, the recreation of a session whose parameters changed on resume or load, and `dispose()`. ## Found along the way, not changed here The consumer's abort race adds an `abort` listener to the cancel signal on each iteration. A listener added to an already-aborted signal never fires, so an abort that lands while the consumer is busy, such as sending an update, is missed. In production the close still ends the turn, through the end of the stream, which is the path this PR waits for. But the same gap can defeat the force-cancel backstop for a wedged Claude Code (issue #680). That gets its own PR next. ## Verification A new turn-events test has the client accept an answer chunk slowly, closes the session while the consumer is still sending it, and checks that the turn's end comes before the close returns. It fails without the change: the close returns first. Build, lint and all 2389 tests pass.
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
/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
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.
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).