What is antigravity-claude-proxy?

Antigravity Claude Proxy is a local server that sits between AI coding tools and a third-party service called Antigravity Cloud Code. The main problem it solves is that tools like Claude Code CLI expect to talk to Anthropic's API, but some users want to route those calls through Antigravity, which provides access to Claude and Gemini models backed by Google Cloud. This proxy translates the request format from Anthropic's API format to Google's format, sends it to Antigravity, and converts the response back before returning it to the calling tool. The project comes with an important warning: Google has been issuing Terms of Service bans on accounts connected to this proxy. The README explicitly states that using it may violate Google's Terms of Service and that accounts have been suspended or shadow-banned as a result. It recommends using a throwaway account rather than your main Google account. Setup involves running the proxy as a background process on your local machine (port 8080 by default), then linking a Google account through either a web dashboard, a command-line flow, or automatically if you have the Antigravity desktop app installed. Once running, you point Claude Code CLI at the local proxy address instead of Anthropic's servers by adjusting a settings file or a few environment variables. The proxy supports multiple Google accounts and includes a web dashboard for account management, quota tracking, and Claude Code configuration. The proxy handles both Claude models and Gemini models. The README provides ready-to-use configuration blocks for both, including which model names to use in each slot (the primary model, the faster sub-agent model, and so on). It supports streaming responses and the extended thinking mode that some Claude models expose. Installation is through npm, either by running it directly with npx or installing it globally. The project is released under the MIT license.