antigravity-mcp-fork

A fork of Kio-pon/antigravity-mcp that adds GPT-planned native multi-parent orchestration, local job supervision, and signed job-event webhooks on top of the upstream Antigravity IDE bridge.

Upstream exposes 6 tools. This fork exposes 8 — the same 6 plus get_agent_job_status and supervise_agent_job.

Provenance

This is a downstream fork, not an independent project.

Five of the nine upstream modules are byte-identical to the base commit: __init__.py, __main__.py, discovery.py, paths.py, protocol.py.

Four were modified to wire in the added features:

The local version string was bumped to 1.1.0.post1 specifically so this fork can never be confused with upstream 1.1.0 — both previously reported 1.1.0 while behaving differently, which made them indistinguishable from a client's point of view.

Related MCP server: Antigravity MCP Bridge

Added modules

These eight modules do not exist upstream:

Tools

Execution model

The intended loop: GPT plans and reviews; Gemini executes.

workflow_settings.json (shipped alongside the package) pins the policy:

{
  "default_model": "Gemini 3.8 Flash (High)",
  "planner": "gpt",
  "mode": "native_multi_parent",
  "min_workers_per_parent": 2,
  "min_agents_per_worker": 2,
  "single_parent_conversation": false,
  "same_ide": true,
  "subagent_model": "inherit",
  "independent_tasks_required": true,
  "require_all_terminal_results": true
}

Backends are tried in order: the local Antigravity language server, then the Gemini REST API. If neither is reachable the job fails with an explicit error — there is deliberately no fallback tier that returns an invented result.

Install

Requires Python 3.9+. Zero runtime dependencies (standard library only).

pip install -e .

Run over stdio:

python -m antigravity_mcp

MCP client configuration:

{
  "mcpServers": {
    "antigravity-mcp": {
      "command": "python",
      "args": ["-m", "antigravity_mcp"],
      "env": { "PYTHONPATH": "D:\\path\\to\\antigravity-mcp-fork\\src" }
    }
  }
}

Environment variables

Shared state warning

paths.py resolves the state directory to %LOCALAPPDATA%\antigravity-mcp on Windows (and the equivalent per-platform location elsewhere). Upstream antigravity-mcp resolves to the same directory.

If you install both, they share one jobs.json. This fork writes extra native_forest* metadata keys that upstream ignores, and upstream writes records lacking those keys. Neither crashes today, but it is shared mutable state between two different codebases. If you run both, pin a separate directory for each:

set ANTIGRAVITY_STATE_DIR=%LOCALAPPDATA%\antigravity-mcp-fork

Status

• Verified on Windows x64 with Python 3.12: the server starts from the fork's own src/ tree, completes the MCP handshake, and lists all 8 tools.

• Upstream notes that only Linux has been verified on real hardware against Antigravity IDE v1.107.0.

• No automated test suite is included in this repository yet; upstream's tests/ directory was not carried over because the fork's modified modules diverge from it.

License

MIT. Original work Copyright (c) 2026 Kio-pon, see LICENSE.

Fork modifications are distributed under the same MIT terms.