14b2233192
A follow-up to #1310, from its review, which found no regressions but two wrong answers. Both come from one choice in #1310: a request from an agent without a `liveBackgroundTasks` record put v2's foreground work in `requires_action`. **When an agent has no record:** - **A teammate:** it never gets one. - **A settled subagent:** settling deletes its record, and settling didn't re-check open requests. - **A foreground subagent nested in a background one:** Claude Code leaves it out of `background_tasks_changed`, so the level reconciliation prunes it after two activations. The main conversation waits on none of them. A background subagent's request that the consumer read before its `task_started` also flickered from `requires_action` to `running`. ## What changes - **An agent without a record no longer blocks the foreground work.** A subagent the main conversation waits on has a record by the time it asks: its `task_started` comes first on the wire, and nothing prunes it while the main turn waits. When the consumer reads the request first, the `task_started` checks again, so `requires_action` comes slightly later instead of a flicker for background subagents. - **Settling a task re-checks** the open requests. - **The comment on `nativeSubagentParentByToolUseId`** no longer claims `parent_task_id` is unread. ## Tests - **Replaced:** "stops waiting for a request once its subagent turns out to run in the background". The new test checks that a request read before its `task_started` doesn't block, then blocks once the `task_started` says foreground. - **New:** a foreground subagent's open request stops blocking once Claude Code stops that subagent. - **Mutations:** restoring "no record blocks" fails both tests; dropping the re-check at settle fails the second. - `npm run check` and the full suite pass, with no golden file changes.
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).