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## Problem A v1 report's `_meta` belongs to that report, and the agent gives each report its own `_meta.claudeCode` keys. A v2 client stores a tool call's `_meta`, and any report that carries `_meta` replaces it (`tool-calls.mdx`; the migration guide since agentclientprotocol/agent-client-protocol#2355). So a v2 client kept only the last report's keys. For example, a result's `{ toolName }` replaced the denial reason that came before it. On top of that, a PostToolUse hook stored the whole `tool_response` in `_meta`, which for a Write is the whole file text. ## Change All of this is v2 only. No v1 or AIR output changes, and no v1 golden changes. - **Stored `_meta` (`src/v2/tool-call-meta.ts`).** The v2 bridge keeps each tool call's `_meta` the way the client stores it. `claudeCode` keys merge one by one, and every other key replaces whole, the same model `ToolCallFieldTracker` uses. - A report that changes the stored `_meta` carries all of it. - A report that changes nothing carries no `_meta`, which leaves the stored value unchanged. - A permission request's subject always carries the stored `_meta`, since a client can show the request on its own. - The tool call's first report starts from nothing. - **`toolName` becomes `name`.** `claudeCode.toolName` repeats the tool's name, which v2 has a field for. It becomes the `name` of a tool call that has none yet, and is left out otherwise. A memory recall gets a `name` this way. Subagent routing still reads `toolName` on the agent's v1 reports, before the bridge. - **The `toolResponse` AIR gets.** A v2 client also keeps `_meta`, so it gets AIR's trimmed `toolResponse`: - a hook carries only the `status` and `isAsync` markers, not output the content already shows; - a denial carries the SDK message only when it differs from the reason. ## Evidence - **v2 goldens:** 28 change. Most only lose `toolName`. Hook reports lose the repeated stdout or file text. Memory recall gains `name`. The denial keeps its reason type and message. Subagent tool calls and their permission subjects keep `parentToolUseId`. - **Live, CLI 2.1.293 on Haiku, v2:** a Write and a Bash command arrived with `name` on their first report and no `_meta` at all. - **Tests:** 7 unit tests for the stored `_meta`. - **Mutation checks:** removing any of these 9 rules fails at least one test: - naming once; - leaving `toolName` out; - merging with earlier `claudeCode` keys, which also fails the `subagent-late-child-update` golden; - keeping other keys; - omitting unchanged `_meta`; - starting fresh; - the subject's stored `_meta`; - the bridge wiring; - the trimmed `toolResponse`. Forgetting a closed session's tool calls is memory cleanup that no test observes, like `V2Terminals.forget`. A limit of 2048 tool calls also bounds the memory. - `npm run check`, build and all 2820 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).