AGO Adapter (Antigravity OpenAI Adapter)

An adapter that exposes an OpenAI-compatible API to communicate with antigravity-claude-proxy. This allows using applications that expect the OpenAI API with Claude and Gemini models available through Antigravity.

How it Works

┌──────────────────┐     ┌─────────────────────┐     ┌────────────────────────────┐
│  OpenAI-enabled  │────▶│  This Adapter       │────▶│  antigravity-claude-proxy  │
│  Application     │     │  (OpenAI → Anthropic│     │  (Anthropic → Google       │
│  (Chat API)      │     │   format)           │     │   Generative AI)           │
└──────────────────┘     └─────────────────────┘     └────────────────────────────┘

1. Receives requests in OpenAI Chat Completions API format.
2. Converts to Anthropic Messages API format.
3. Forwards to antigravity-claude-proxy.
4. Converts responses back to OpenAI format.
5. Supports full streaming (SSE).
6. Automatic Proxy Management: Can automatically start the upstream proxy if it's running on localhost.
7. Transparent Routing: Unknown routes (like WebUI) are automatically proxied to the upstream.

Prerequisites

• Node.js 18 or higher
• antigravity-claude-proxy (automatically handled if on localhost, otherwise needs to be running)

Installation

Option 1: npm / npx

# Run directly with npx (automatic proxy start)
npx @pedrofariasx/antigravity-openai-adapter start

# Or install globally
npm install -g @pedrofariasx/antigravity-openai-adapter
antigravity-openai-adapter start

Option 2: Docker

# Using Docker Compose
docker-compose up -d

# Using Docker Stack (Swarm)
docker stack deploy -c docker-stack.yml antigravity

Option 3: Clone Repository

git clone https://github.com/pedrofariasx/antigravity-openai-adapter
cd antigravity-openai-adapter
npm install
npm start

Quick Start

1. Start the Adapter

npx @pedrofariasx/antigravity-openai-adapter start

By default, the adapter will:

1. Start on http://localhost:8081.
2. Check if antigravity-claude-proxy is needed.
3. Automatically run npx antigravity-claude-proxy@latest start if the upstream is configured to localhost.
4. Proxy all non-API requests (like the WebUI) to the upstream proxy.

2. Use with OpenAI Applications

Configure your application to use:

Base URL: http://localhost:8081/v1
API Key: any-value (or your configured API_KEY)

API Endpoints

| Endpoint | Method | Description | |----------|--------|-----------| | /v1/chat/completions | POST | Chat Completions (main) | | /v1/models | GET | List available models | | /health | GET | Health Check | | /* | * | Proxied to antigravity-claude-proxy (WebUI, etc) |

Configuration

The adapter supports configuration via config.json, environment variables, or CLI arguments. It also supports .env files.

Environment Variables

| Variable | Description | Default | |----------|-----------|--------| | PORT | Server port | 8081 | | UPSTREAM_URL | antigravity-claude-proxy URL | http://localhost:8080 | | API_KEY | API Key for this adapter | - | | UPSTREAM_API_KEY | API Key for upstream proxy | test | | AUTO_START_PROXY | Auto-start proxy via npx | true | | DEBUG | Enable debug logging | false |

CLI Arguments

antigravity-openai-adapter start --port=3000 --upstream=http://localhost:9000 --no-proxy --debug

• --no-proxy: Disables automatic starting of the upstream proxy.

Features Supported

✅ Supported

• Chat Completions API
• Streaming (SSE)
• System messages
• Multi-turn conversations
• Tool/Function calling
• Vision (Images)
• Temperature, top_p, max_tokens, stop sequences
• Unified routing for API and WebUI

❌ Not Supported

• Embeddings (/v1/embeddings)
• Legacy Completions (/v1/completions)
• Assistants API, Files API, Fine-tuning

Development

# Clone and install
git clone https://github.com/pedrofariasx/antigravity-openai-adapter
cd antigravity-openai-adapter
npm install

# Run in development mode (with watch)
npm run dev

# Run tests
npm test

License

MIT