d599333b72
Found while planning the permission requests of opt-in ACP v2 support (step 5 of the v2 plan). It affects ACP v1 clients that show native subagent sessions (`subagents` capability, or AIR's native subagent sessions). ## Problem For such a client, a native subagent's permission request or AskUserQuestion goes to the subagent's child session. The agent counted the open request on that session id, but child sessions aren't in `sessions`, so `withPendingUserInput` counted nothing: - **Steering:** a message steered while the subagent's request was open didn't see it, so it went out with interrupting priority instead of `later`, the priority used while the user has a prompt open. - **Turn state:** the turn didn't report that it awaits the user. That's `requires_action` in ACP v2, though the v2 surface doesn't show child sessions today, so v2 isn't affected yet. ## Change The request is still sent to the child session, but it now counts against the owner session, whose turn and steering it blocks. Both paths take the owner id: `requestPermissionFromClient` already had it (`ownerSessionId`), and `handleAskUserQuestion` gets it next to the session it sends the elicitation to. ## Verification The existing "uses priority:'later' while … is pending" test gains two cases: a subagent's permission request and a subagent's AskUserQuestion, both sent to an announced child session. Each fails when its half of the fix is reverted. Build, lint and all 2390 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).