agy-acp-bridge

Agent Client Protocol (ACP) adapter bridge for the Google Antigravity CLI (agy) built on native JSON-stream output.

Unlike older adapters that rely on polling and parsing local SQLite database states (StreamPoller), this adapter uses agy's native --output-format stream-json print mode. It is entirely event-driven, streaming message chunks and tool states in real-time.

Installation

Install globally via npm:

npm install -g agy-acp-bridge

If the official Antigravity CLI (agy) is not already installed, the npm package downloads and runs Google's installer for the current platform. The official installer selects the latest release and verifies its SHA-512 checksum before installing it. Existing agy installations are left in place because the CLI keeps itself up to date.

The bridge does not redistribute Google's platform binaries inside the npm tarball. To install only the ACP bridge (for example in an offline build or when provisioning agy separately), disable the automatic installer:

AGY_ACP_SKIP_CLI_INSTALL=1 npm install -g agy-acp-bridge

On Windows PowerShell:

$env:AGY_ACP_SKIP_CLI_INSTALL = "1"
npm install -g agy-acp-bridge

If agy is installed in a non-standard location, point the bridge at it with AGY_ACP_COMMAND=/absolute/path/to/agy.

To customize the CLI prompt execution timeout (default: 30m to prevent premature stream cutoffs on long tasks), pass --print-timeout <duration> or set AGY_ACP_PRINT_TIMEOUT=<duration>:

AGY_ACP_PRINT_TIMEOUT=1h agy-acp

Or run directly via npx:

npx agy-acp-bridge

Features

• No DB Polling: Listens to the structured JSON events streamed directly on agy's stdout.
• MCP Server Support: Full Agent Client Protocol MCP integration (stdio, sse, http), dynamically synced into <cwd>/.agents/mcp_config.json.
• Session History Preservation: Maps ACP session IDs to agy's --conversation <id> context and persists them under ~/.agy-acp-state.json. Supports session/new, session/load, session/resume, session/list, and session/delete.
• Robust UTF-8 Streaming: Accurately buffers streaming chunks across multi-byte character boundaries without corrupting non-ASCII (e.g., Chinese) outputs.
• Cancellation: Gracefully handles session/cancel by terminating active sub-processes using SIGINT.
• Clean Output Channel: Routes all internal logging and CLI stderr to stderr to avoid polluting the JSON-RPC pipe.
• Pass-through Configuration: Forwards command-line flags (like --dangerously-skip-permissions or --sandbox) to child processes.

Development

1. Install dependencies:

   npm install

2. Build the project:

   npm run build

Editor Integration

Zed Configuration

Add the adapter as a custom agent in your Zed settings.json:

{
  "agent_servers": {
    "Google Antigravity": {
      "command": "agy-acp",
      "args": [
        "--dangerously-skip-permissions"
      ]
    }
  }
}

Or using npx:

{
  "agent_servers": {
    "Google Antigravity": {
      "command": "npx",
      "args": [
        "agy-acp-bridge",
        "--dangerously-skip-permissions"
      ]
    }
  }
}

[!NOTE] Since the adapter runs the CLI in headless print mode (--print), any tool execution that requires user confirmation will automatically fail unless --dangerously-skip-permissions is supplied. Alternatively, you can whitelist actions in your Antigravity settings.json file.