agy-mcp

An MCP server that lets Claude Code drive agy (Google's Antigravity CLI) as a tool — for a second opinion, or to actually execute a plan.

Why

Claude Code writes the plan; agy (a separate model/agent) either reviews it (agy_ask) or executes it (agy_execute) in its own isolated git worktree. Session state (which agy conversation maps to which of our sessions) is kept in a small SQLite database, so both tools support multi-turn conversations.

Related MCP server: agy MCP Server

Tools

• agy_ask(prompt, session_id?, conversation_id?, workspace?) — Read-only. Runs agy in --mode plan (it cannot edit files). Pass session_id to continue a conversation this server started, or conversation_id to adopt an existing agy CLI conversation (e.g. one you started in your own terminal — this does not work for Antigravity IDE conversations, which use a separate store).

• agy_execute(plan, session_id?, conversation_id?, workspace?) — Hands agy full write access (--dangerously-skip-permissions) inside a fresh git worktree, never the real working tree. Changes are auto-committed to a branch (agy/<short-id>) so they survive even if the worktree is later removed — unless the pre-commit secret scan blocks it (see below). Disabled unless AGY_MCP_ALLOW_EXECUTE=1 is set in the server's environment.

• agy_list_sessions() — Lists all known sessions with status, workspace, and worktree path.

• agy_close_session(session_id, remove_worktree?) — Closes a session. By default the worktree/branch are left on disk for manual review; remove_worktree: true deletes the worktree (irreversible for anything not committed).

Setup

npm install
npm run build

Register it with Claude Code (e.g. in ~/.claude.json, alongside your other mcpServers):

"agy-mcp": {
  "type": "stdio",
  "command": "node",
  "args": ["/absolute/path/to/agy_mcp/dist/index.js"],
  "env": { "AGY_MCP_ALLOW_EXECUTE": "1" }
}

Omit AGY_MCP_ALLOW_EXECUTE to keep agy_execute disabled and only allow agy_ask (read-only).

Safety notes

agy_execute isolates the git working tree (via a worktree) but does not sandbox the filesystem or network — see PILOT_TEST_REPORT.md for the audit that drove the current mitigations:

• child process env is allowlisted (PATH, HOME, TMPDIR, LANG, LC_ALL only — no inherited secrets)

• a pre-commit scan blocks commits containing likely secrets (AWS/GitHub/Slack key shapes, private key headers, .env-style filenames) and leaves the worktree untouched for manual review

• new-conversation creation is serialized server-wide to avoid a conversation-id race

• ask and execute sessions can't be resumed across each other

• a timed-out agy process (and its subprocess tree) is killed, not left orphaned

None of this replaces running agy_execute in a disposable, credential-free, egress-restricted environment for anything beyond low-stakes local use — see the report's "Conditional pilot controls" for the full checklist.

Requirements

• Node.js ≥ 22.5 (uses the built-in node:sqlite)

• The agy CLI on PATH (override with AGY_BIN), already authenticated

• Git (for agy_execute's worktree isolation)