google-antigravity-acp

An Agent Client Protocol (ACP) server for Google Antigravity.

This project enables any ACP-compatible client (such as Zed, OpenClaw, Neovim, and other developer tools) to communicate with Google Antigravity using standard JSON-RPC 2.0 over stdio.

The same npm package also ships a native OpenClaw CLI backend. It exposes Antigravity models under the google-antigravity-cli/* model namespace while preserving Antigravity conversation IDs, streamed responses, native tool-call events, cancellation, and usage reporting.

How It Works

Google Antigravity ships with an official command-line executable (agy). Under the hood, agy includes a headless streaming mode that exchanges newline-delimited JSON (NDJSON) over standard input and output:

agy --input-format=stream-json --output-format=stream-json

google-antigravity-acp bridges this interface to the open Agent Client Protocol (ACP) standard:

• Exposes standard ACP JSON-RPC 2.0 lifecycle methods (initialize, session/new, session/prompt, session/cancel, session/close).
• Maps incoming ACP user messages into stream-json input events.
• Translates agy streaming events into real-time ACP session/update notifications (message chunks, tool calls, and usage stats).
• Automatically discovers the system agy binary (or downloads the official release if missing).

Prerequisites

• Node.js (v18 or higher)
• Google Antigravity CLI (agy) installed and authenticated, or internet access on first run so the official binary can be downloaded automatically.

Usage

Run via npx

npx google-antigravity-acp

Install Globally

npm install -g google-antigravity-acp
google-antigravity-acp

Install as an OpenClaw plugin

openclaw plugins install google-antigravity-acp
openclaw config set plugins.entries.google-antigravity-cli.enabled true

Then select an Antigravity model and require the plugin-owned runtime:

{
  agents: {
    entries: {
      fast: {
        model: {
          primary: "google-antigravity-cli/gemini-3.8-flash-low",
          fallbacks: [],
        },
        models: {
          "google-antigravity-cli/gemini-3.8-flash-low": {
            agentRuntime: { id: "google-antigravity-cli" },
          },
        },
      },
    },
  },
}

Authentication remains owned by the official agy installation. Normal agent turns use Antigravity's native tools, and their start/result events are surfaced to OpenClaw.

For OpenClaw runs with an exact tool cap, the backend creates a private per-run Antigravity home, denies all native file, shell, and web permissions, passes through only the minimum authentication and conversation state, and exposes only OpenClaw's host-isolated MCP bridge. Antigravity and the bridge both enforce the requested OpenClaw tool list. Ambient user/workspace plugins, skills, hooks, rules, and agents are excluded. Exact-cap runs require Antigravity CLI 1.1.9 or newer and fail closed when native tools are requested; unrestricted turns keep the normal native tool behavior and additionally receive the OpenClaw MCP bridge.

Client Configuration

Configure your ACP-compatible editor or client to launch google-antigravity-acp over stdio:

{
  "command": "npx",
  "args": ["-y", "google-antigravity-acp"]
}

CLI Options

Usage: google-antigravity-acp [options]

Agent Client Protocol (ACP) server for Google Antigravity

Options:
  -V, --version             output the version number
  -b, --binary-path <path>  Path to custom agy binary
  -m, --model <model>       Default model for agent sessions
  -e, --effort <effort>     Reasoning effort (low, medium, high)
  --no-skip-permissions     Do not auto-approve permissions in agy
  -h, --help                display help for command

License

MIT