Important

Disclaimer: For Educational and Research Purposes Only. This project is a proof-of-concept designed to demonstrate protocol translation and proxy logic. It is not intended for commercial use. The authors and contributors are not responsible for any misuse, account suspensions, or legal consequences resulting from the use of this software. Use at your own risk and in accordance with your service providers' Terms of Service.

Antigravity Proxy for Cursor

A high-fidelity bridge that brings Google's latest Gemini 3 and Claude 4.5 models directly into your Cursor IDE with full Agentic and Composer support.

Why Antigravity Proxy?

Google's advanced agentic models (internal versions of Gemini/Claude) use a specific protocol that standard OpenAI-compatible clients (like Cursor) cannot understand natively. This proxy:

1. Translates Protocols: Converts OpenAI requests into Google's Agentic format.
2. Injects Thought Signatures: Automatically handles the complex reasoning traces required for tool calling.
3. Bridges Authentication: Securely extracts your local Cloud Code session tokens so you don't need manual API keys.

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🛠️ How it Works: The Cloudflare Tunnel

When you run npm start, the engine launches two processes:

1. Local Proxy Server: Runs on localhost:3000.
2. Cloudflare Quick Tunnel: Creates a secure, temporary HTTPS bridge from the internet's edge directly to your local proxy.

Why is the Tunnel necessary?

• HTTPS Requirement: High-security IDEs like Cursor often require a valid, trusted HTTPS endpoint to talk to custom models.
• Zero-Config Networking: It allows the proxy to work through firewalls and VPNs without you having to open any ports or touch router settings.
• Security: The tunnel provides a random, difficult-to-guess URL that is only active while your process is running.

Caution

Dynamic URLs: Because we are using Cloudflare's Quick Tunnel mode (free version), a fresh URL is generated every time you restart the script. You will need to update the URL in Cursor whenever the terminal shows a new one.

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Prerequisites: The "Session Bridge"

For this proxy to work, it MUST be able to see your local Google authorization.

• Keep Antigravity/VS Code Logged In: You must have the Google Cloud Code (Antigravity) extension installed and be logged in with your account.
• Active Session: The proxy extracts tokens dynamically. If you sign out of the extension, the proxy will stop working until you sign back in.

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Setup Instructions

1. Installation

First, install dependencies. This will automatically download the correct cloudflared binary for your OS:

npm install

2. Start the Proxy

In your terminal, run:

npm start

Watch for the big green rocket icon. Copy the Base URL (e.g., https://random-words.trycloudflare.com/v1).

3. Configure Cursor

1. Open Cursor Settings (Cmd + Shift + J or Click the gear icon).
2. Go to Models > OpenAI.
3. CRITICAL: Enable the "Override OpenAI Base URL" toggle.
4. Paste your New Base URL into the field.
5. (Optional but Recommended) Restart Cursor to ensure the new networking configuration is fully picked up by the internal AI engine.

4. Model Selection

In the Cursor sidebar or Composer, select one of these IDs:

• ag-pro: Gemini 3 Pro (High intelligence, architecture).
• ag-flash: Gemini 3 Flash (Sub-second latency, quick edits).
• ag-sonnet: Claude 4.5 Sonnet (Thinking model, deep reasoning).
• ag-opus: Claude 4.5 Opus (Maximum logic, complex debugging).
• ag-haiku: Gemini 2.5 Lite (Fast and efficient).

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⚠️ Troubleshooting

• 400 Error (Missing Thought Signature): This is fixed! Ensure you are running the latest version of this proxy.
• Invalid URL Error: This means your tunnel URL has changed or expired. Restart the proxy and copy the new URL from the terminal.
• EADDRINUSE: If you see "Address already in use", run lsof -t -i:3000 | xargs kill -9 to clear the previous process.

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Created for the Antigravity Team. Powered by Google Deepmind.