codebuff-agent-acp

Unofficial / community project. This project is not affiliated with, endorsed by, or sponsored by Codebuff, Inc. or the CodebuffAI/codebuff project. "Codebuff" is a trademark of its respective owners; all trademarks are the property of their respective holders. This is an independent, third-party adapter that consumes the publicly available @codebuff/sdk package.

Use the Codebuff agent engine from any ACP-compatible client (such as Zed).

This package implements an ACP agent on top of the official @codebuff/sdk, in the same vein as claude-agent-acp wraps the Claude Agent SDK.

What works

• Streaming assistant output (agent_message_chunk) and reasoning (agent_thought_chunk)
• Tool calls with rich titles, kinds, and file locations, including tool_call_update results
• Permission prompts for mutating/shell tools via session/request_permission
• Sub-agents surfaced as nested tool calls (spawn_agents / Codebuff's file-picker, planner, editor, reviewer, …)
• The model's write_todos plan mirrored as an ACP plan update
• Image inputs
• Persistent sessions: session/load, session/list, session/resume, session/fork, session/close, session/delete — resumable RunState is stored under ~/.codebuff-acp/sessions/
• session/cancel (aborts the in-flight Codebuff run)

Install

npm install -g codebuff-agent-acp
# or run directly without installing:
npx codebuff-agent-acp

Set your Codebuff API key (get one from https://codebuff.com):

export CODEBUFF_API_KEY=cb_...

Use with Zed

Add this to your Zed settings.json:

"agent_servers": {
  "Codebuff": {
    "command": "codebuff-agent-acp",
    "args": []
  }
}

Then open the Agent Panel and start a new Codebuff thread. (Run acp: open acp logs from the command palette to inspect the wire traffic.)

Run from source

npm install
npm run build       # outputs to dist/
./dist/index.js     # or: npm start
npm run dev         # run via tsx without building

You can sanity-check the stdio server by piping a raw JSON-RPC initialize:

echo '{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"protocolVersion":1,"clientCapabilities":{}}}' | npm start

Development

Tooling uses oxlint for linting and oxfmt (Prettier-compatible) for formatting. Both are pre-configured (.oxlintrc.json, .oxfmtrc.json).

npm run lint          # oxlint src tests
npm run lint:fix      # apply safe autofixes
npm run format        # oxfmt src tests (write)
npm run format:check  # oxfmt --check (CI uses this)
npm run typecheck     # tsc --noEmit over src + tests
npm run test          # vitest run (70 tests)
npm run check         # typecheck + lint + format:check + test

CI (.github/workflows/ci.yml) runs npm run check && npm run build on every push and pull request.

Releasing

Releases are published to npm by the Release workflow (.github/workflows/release.yml) when a GitHub Release is published. It mirrors the canonical guide and publishes with provenance.

1. Set the NPM_TOKEN repository secret (an automation/automation-class token, 2FA-exempt) and create a release environment (optional but recommended).

2. Bump version in package.json and commit.

3. Create a GitHub Release on the matching tag:

   git tag vX.Y.Z
   git push origin vX.Y.Z
   gh release create vX.Y.Z --verify-tag --generate-notes

The workflow verifies the release tag matches package.json, runs npm run check, builds, and runs npm publish --provenance --access public (requires the workflow's id-token: write permission, which is already set).

Configuration

The Codebuff API key is resolved in this order:

1. CODEBUFF_API_KEY environment variable.
2. The key saved by --setup (below), stored at ~/.codebuff-acp/config.json.

Interactive setup (Terminal Auth)

npx codebuff-agent-acp --setup

Prompts for your Codebuff API key (get one from https://codebuff.com → Profile → API Keys) and saves it locally. ACP clients that drive the agent can also trigger this via the terminal auth method advertised in initialize (args: ["--setup"]).

Environment variables

| Env var | Default | Description | | ------------------- | ----------------- | --------------------------------------------------- | | CODEBUFF_API_KEY | none | Codebuff API key (overrides the saved key) | | CODEBUFF_AGENT | base | Codebuff agent id to run (e.g. base, base_free) | | CODEBUFF_ACP_HOME | ~/.codebuff-acp | Where config + session files are stored |

A client may also pass an API key at runtime via the authenticate request's _meta.codebuff.apiKey (it's persisted for future sessions).

Limitations

• Permission prompts are advisory, not hard-gating. Codebuff executes its built-in tools itself and only reports them via events, so a rejected permission marks the tool call as failed in the UI but cannot always un-execute it. (True pre-execution gating would require re-implementing Codebuff's write_file / str_replace / apply_patch / run_terminal_command via the SDK's overrideTools — a follow-up.)
• Client-provided MCP servers are not wired into Codebuff (the SDK exposes MCP config on agent definitions, not the client). mcp_capabilities is advertised as unsupported.
• Session history replay on session/load is text-only (tool history is not reconstructed).

License

Apache-2.0