Agy Server

Bridge between Claude and Google Antigravity's agy CLI — let Claude Code (or any MCP client) drive the Antigravity agent through tool calls.

graph LR
    A[Claude Code] --> B[agy MCP Server]
    B --> C[agy CLI]
    C --> D[Antigravity / Gemini]

    style A fill:#FF6B35
    style B fill:#4A90E2
    style C fill:#00D4AA
    style D fill:#FFA500

This project mirrors the architecture of codex-mcp-server but wraps agy instead of codex.

How it works

agy exposes a non-interactive print mode: agy -p "<prompt>" runs a single prompt (the prompt is the value of -p) and prints the response to stdout. This server spawns agy -p "<prompt>" with the prompt as an argument, always closes stdin so agy never blocks waiting for input, and returns stdout as the MCP tool result. (agy only reads the prompt from stdin when -p is empty; a bare -p with no value errors with "flag needs an argument".)

Requirements

• agy CLI v1.0.3+ on your PATH (agy --version). It ships with Google Antigravity.
• You must be logged into Antigravity — agy reuses the desktop app's credentials, so there is no API key to configure here.

Install

Prerequisite (all methods): the agy CLI (v1.0.3+) must be installed and logged into Antigravity on the machine that runs the MCP server.

A) Via GitHub + npx (no manual clone)

claude mcp add agy-cli -- npx -y github:toonPt0473/agy-mcp-server

npx clones the repo and runs the prepare script (tsc) to build dist/ on first install, then launches the server. Requires git and Node on PATH. Updates: bump the repo; npx re-fetches on the next cold install (or clear the npx cache).

B) From a local clone

git clone https://github.com/toonPt0473/agy-mcp-server.git
cd agy-mcp-server
npm install            # runs the build automatically via the `prepare` script
claude mcp add agy-cli -- node "$(pwd)/dist/index.js"

C) Global binary (decoupled from the source folder)

npm install -g .       # in the cloned repo; exposes the `agy-mcp-server` bin
claude mcp add agy-cli -- agy-mcp-server

This repo also ships a project-scoped .mcp.json pointing at dist/index.js, which Claude Code picks up automatically when run from the project directory.

Tools

Tool	Description
agy	Run a prompt through agy -p (print mode) with optional model, session continuation, extra dirs, sandbox, and skip-permissions
models	List the models available to agy (agy models)
listSessions	View active conversation sessions
ping	Test server connection
help	Get agy --help output
changelog	Show agy changelog / release notes

agy tool parameters

Parameter	Type	Default	Description
prompt	string	— (required)	The task/question. Passed as the value of agy -p.
model	string	—	Model for this call (--model). Use a name from the models tool, e.g. Claude Opus 4.6 (Thinking). Omit to use agy's default (or AGY_MCP_DEFAULT_MODEL).
sessionId	string	—	Multi-turn context. First turn = fresh conversation; later turns continue it.
resetSession	boolean	false	Start a fresh conversation for this session.
conversationId	string	—	Resume a specific agy conversation (--conversation <id>).
continueConversation	boolean	false	Force agy --continue (most recent conversation).
addDirs	string[]	—	Extra workspace dirs (--add-dir, repeatable).
sandbox	boolean	false	--sandbox (terminal restrictions).
skipPermissions	boolean	false	⚠️ --dangerously-skip-permissions — auto-approve all tool use. Needed for agy to run tools unattended.
printTimeout	string	5m	--print-timeout (Go duration, e.g. 90s, 1h30m).

Examples

Use agy to explain the auth flow in this repo
Use the models tool to see which agy models are available
Use agy with model "Claude Opus 4.6 (Thinking)" to review this design
Use agy with sessionId "refactor" to analyze this module
Use agy with sessionId "refactor" to now implement the change   # continues the same conversation
Use agy with skipPermissions true and addDirs ["./src"] to refactor and write files

Selecting a model

agy v1.0.5+ supports choosing a model. List what's available with the models tool (runs agy models), then pass the exact name as the model parameter of the agy tool — names contain spaces/parentheses and are passed safely as a single argument, e.g. Claude Opus 4.6 (Thinking) or Gemini 3.5 Flash (High).

Precedence: per-call model arg → AGY_MCP_DEFAULT_MODEL env → omitted (agy uses its own default). An unknown model name is not rejected — agy falls back to its default. Requires agy ≥ v1.0.5 (older versions have no --model flag).

Session model & limitations

• agy print mode does not emit a conversation ID, so multi-turn within a sessionId uses agy --continue (continue the most recent conversation).
• Because "most recent" is global to agy, avoid interleaving multiple sessions or running agy manually in the middle of a session — the continuation could attach to the wrong conversation. For precise resume, pass a conversationId you obtained from the Antigravity app.
• Without skipPermissions: true, a prompt that makes agy want to use a tool may block until printTimeout, since approvals can't be given non-interactively. Use skipPermissions for agentic/file-writing tasks; leave it off for Q&A.

Environment variables

• AGY_BIN — path to the agy binary (default: agy on PATH).
• AGY_MCP_DEFAULT_MODEL — default --model when not set per-call (default: none → agy's own default).
• AGY_MCP_PRINT_TIMEOUT — default --print-timeout when not set per-call (default 5m).
• AGY_MCP_LOG_DIR — enable conversation logging into this directory (see below).
• AGY_MCP_LOG_FILE — enable conversation logging into this single file (overrides AGY_MCP_LOG_DIR).
• STRUCTURED_CONTENT_ENABLED — emit structuredContent in results (1/true/yes/on). Off by default; _meta is always included for Claude Code.

Conversation logging

Every agy tool call (the prompt Claude sent and the response agy returned) can be appended to a Markdown transcript. Logging is off by default; enable it by setting one of:

• AGY_MCP_LOG_DIR=/path/to/dir → one file per day: agy-conversations-YYYY-MM-DD.md
• AGY_MCP_LOG_FILE=/path/to/file.md → a single file (takes precedence)

Set it in the env block of your .mcp.json, e.g.:

{
  "mcpServers": {
    "agy-cli": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "github:toonPt0473/agy-mcp-server"],
      "env": { "AGY_MCP_LOG_DIR": "/abs/path/to/project/.agy-logs" }
    }
  }
}

Each entry records the timestamp, mode (fresh/continue/resume), sessionId, conversationId, duration, flags (sandbox/skipPermissions/addDirs), and the full prompt and response. Logging failures are reported to stderr but never break the tool. Add the log directory to .gitignore if you don't want transcripts committed.

Development

npm install     # install dependencies
npm run dev     # run from source with tsx
npm run build   # compile to dist/
npm test        # run the test suite
npm run lint    # eslint
npm run format  # prettier

License

ISC