Found while mapping commands to ACP v2 display terminals (#1240). It affects Zed and plain ACP v1 terminal clients and the v2 surface. **AIR is unchanged.** ## Problem The agent reported every command's exit with a number, even when it didn't know the code: - **any failure as 1.** A command that exited with 2, or a denied command that never ran, showed "Exited with code 1". - **a backgrounded command as 0 when it launched**, though it's still running. - **an interrupted command as 1**, and a non-zero code that Claude Code accepted as a success (grep with no matches) as 0. ## Change `CommandOutput.exitCode` is now optional. `BashReporter` sets it only when the tool result says it. I checked each source against the Claude Code 2.1.287 binary: - **a failure:** the `Exit code N` line that starts Claude Code's text of a command that exited with a failing code (`rE`/`JPr` for a `ShellError`). A failure that names none, such as a denial or a spawn error, has no code. - **a success:** 0, unless the structured `BashOutput` says otherwise. Claude Code accepts a non-zero code as a success only with a `returnCodeInterpretation`, such as grep's "No matches found" or diff's "Files differ". An interrupted command (an Esc interrupt returns a success with `interrupted: true`) and a backgrounded one have no code either. - **the code-execution block:** its `return_code`, as before. An unknown code goes out as: - **v1, Zed and plain clients:** `_meta.terminal_exit.exit_code: null`. The v1 `TerminalExitStatus` allows null. Zed (`as_u64()` → `None`) and Delta's v1 adapter (`Option<u32>`) read it as an optional code. Zed then shows a failed command as failed, without the "Exited with code N" tooltip, and every other exit as before. `compare.ts` allows the null code against the origin/main baseline, a documented difference like the `mcp` command in #1218. - **v2:** `exitStatus` without `exitCode`, which the v2 schema treats the same as null. - **AIR:** the numbers it always got (1 for a failed or interrupted command, else the code, or 0). Whether AIR accepts a null code is unchecked, so this stays out of AIR's contract. The command fact carries `interrupted` for that. The AIR golden files and `docs/air-extensions.md` don't change. ## For review - **Interrupted commands** no longer show as failed in Zed, since the tool call completes and no code is known. Their output still ends with "[Command was aborted before completion]". ## Not changed - **A backgrounded command's terminal still exits at launch**, now without a code. It could stay running until the task's `task_notification`. That needs the task's end routed to the terminal, also on replay, so it's a separate change. - **Replay has no `tool_use_result`** (the same gap as replayed diffs), so a replayed success still reports 0 when Claude Code interpreted the code or backgrounded the command. ## Verification A table test pins, for each kind of exit, the code Zed gets and the number AIR gets: a success, a failure that names its code, one that names none, an interrupted, a backgrounded, and an interpreted command. A unit test covers the v2 `exitStatus` without a code. Removing any one of the rules, including AIR's, fails tests. Golden files change for 3 v2 scenarios, each on its exit line only. Build, lint and all 2399 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).