ythx-101/antigravity-bridge

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[!CAUTION] ⚠️ Risk Warning — Read Before Use

This project turns a desktop client into a headless API via CDP injection. This violates Antigravity’s Terms of Service and carries real risks:

• Account throttling — Rate limits, degraded responses, shadow-banning
• Account ban — Your Google account may be suspended, potentially affecting other Google services (GCP, Workspace, Gmail)
• Detection is trivial — CDP debugger attachment, Security.setIgnoreCertificateErrors, and non-human interaction patterns (zero typing delay, no cursor movement) are all easily detectable

Protect yourself:

1. 🚫 Never use your primary Google account — Register a throwaway account
2. 🐢 Add delays between requests — Mimic human typing speed, avoid high concurrency
3. 🧪 Personal research only — Do not use as a production API or multi-user backend
4. 💀 Expect breakage — This is a cat-and-mouse game; the channel can be killed at any time

Use at your own risk. The authors are not responsible for any account actions taken by Google/Antigravity.

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😡 The Problem

“Opus 4.6 API costs hundreds per month” “Gemini 3.1 Pro is free but has no convenient API” “I want my agent to use multiple models without paying for each”

Antigravity Bridge wraps Antigravity — a free AI desktop app by Google — into a standard REST API via Chrome DevTools Protocol (CDP). One endpoint, six free models.

🚀 Quick Start

1. Install & Start

# Install Antigravity from https://antigravity.com (macOS only)

# Clone this repo
git clone https://github.com/ythx-101/antigravity-bridge.git
cd antigravity-bridge

# Install dependency
pip install websockets

# Start Antigravity with CDP
bash scripts/start_antigravity.sh

# Start the bridge
python3 scripts/bridge.py

2. Use the API

# Chat with Opus (free!)
curl -X POST http://localhost:19999/chat \
  -H 'Content-Type: application/json' \
  -d '{"prompt":"Explain quantum computing","model":"Claude Opus 4.6 (Thinking)"}'

# Async mode (recommended for long tasks)
curl -X POST http://localhost:19999/async \
  -d '{"prompt":"Deep analysis...","timeout":600}'
# → {"status":"accepted","task_id":"abc123"}
curl http://localhost:19999/task/abc123

# New conversation (clear context)
curl -X POST http://localhost:19999/new

# Health check
curl http://localhost:19999/health

🤖 Available Models

📡 API Reference

📊 Architecture

Your Agent / Script
    │
    ├── curl http://localhost:19999/chat
    │
    └── bridge.py (:19999)
          │ WebSocket (CDP)
          ▼
        Antigravity (CDP :9229)
          │ Security.setIgnoreCertificateErrors ← v1.3.0 fix
          ▼
        language_server_macos_arm
          │ gRPC over TLS
          ▼
        googleapis.com (AI models)

🔧 How It Works

1. Antigravity runs with --remote-debugging-port=9229 (auto-configured via argv.json)
2. bridge.py connects via CDP WebSocket to the Antigravity chat UI
3. Messages are injected into the Lexical editor via document.execCommand('insertText')
4. Responses are polled from the DOM until completion markers appear
5. SSL Fix: Antigravity’s language_server uses a self-signed cert (CN=localhost). The bridge calls Security.setIgnoreCertificateErrors to allow the renderer’s fetch() to communicate with it

⚠️ Known Issues & Solutions

“Messages send but no response” (most common)

Root cause: Electron’s fetch() rejects the self-signed SSL cert used by language_server_macos_arm.

Fix (applied in v1.3.0): The bridge automatically calls Security.setIgnoreCertificateErrors({ignore: true}) before each chat.

“gRPC connection fails”

The language_server connects to daily-cloudcode-pa.googleapis.com via gRPC. If this endpoint is unreachable (e.g., blocked by firewall), models will show as placeholders and won’t respond.

Fix: Ensure your network can reach googleapis.com.

Planning mode gets stuck

Some long prompts trigger Antigravity’s “Planning” mode which can hang.

Fix: The bridge auto-switches to “Fast” mode. Keep prompts concise.

📁 Files

antigravity-bridge/
├── README.md
├── CHANGELOG.md
├── LICENSE
├── SKILL.md
└── scripts/
    ├── bridge.py             # REST API server (v1.3.0)
    └── start_antigravity.sh  # Mac startup helper

📝 Requirements

• macOS with Antigravity installed
• Python 3.8+ with websockets package
• Network access to googleapis.com

License

MIT