Antigravity Claude Proxy: use Antigravity's Claude and Gemini models in Claude Code, at your account's risk

Read the warning first

This project is unusual in leading with a caution, and that caution is the most important thing to convey. The README warns that Google has been issuing Terms of Service violation bans on accounts connected to this proxy, and says to use it at your own risk. Its expandable warning goes further: a small number of users have reported Google accounts being banned or shadow-banned, this is an unofficial tool not endorsed by Google, and by using it you accept that your account may be suspended or permanently banned.

The README's own recommendation is to not use your main account and to use a burner account instead, optionally added to your main account's family plan. Any honest description of this tool has to put that up front: it is technically capable, but it works by using Antigravity's Cloud Code in a way Google may treat as a violation, and the consequence falls on your Google account, not on the software.

What it is and how it works

With that understood, the mechanism is clean. The proxy exposes an Anthropic-compatible API backed by Antigravity's Cloud Code, letting you use Claude and Gemini models with the Claude Code CLI and OpenClaw, also known as ClawdBot. It is a Node.js server, MIT licensed, published on npm.

The README's diagram shows the flow: Claude Code sends requests in Anthropic Messages API format; the proxy uses OAuth tokens from added Google accounts, or Antigravity's local database; it transforms the request into Google Generative AI format with Cloud Code wrapping; it calls Antigravity's Cloud Code API; and it converts the response back into Anthropic format with full thinking and streaming support. The value is that any tool that already speaks the Anthropic API, chiefly Claude Code and OpenClaw, can be pointed at models served through Antigravity without code changes.

Installing and starting the proxy

It needs Node.js 18 or later, and either Antigravity installed for single-account mode or Google accounts for multi-account mode. The recommended install is npm, and you can run it without installing:

npx antigravity-claude-proxy@latest start

Or install globally and use the short acc command:

npm install -g antigravity-claude-proxy@latest
acc start

The server launches as a background process on http://localhost:8080 by default and survives closing the terminal. A small set of commands manages its lifecycle: acc stop, acc restart, acc status to check health and PID, acc ui to open the dashboard, and acc start --log to run in the foreground with visible logs. A custom port is set with the PORT environment variable.

Linking accounts

Authorising the proxy has three routes. The recommended one is the web dashboard: with the proxy running, open http://localhost:8080, go to the Accounts tab, click Add Account and complete the Google OAuth flow in the popup. For a server with no browser, the WebUI has a manual authorisation mode where you copy the OAuth URL, authorise on your local machine, and paste the code back.

The CLI route works on desktop or headless machines:

antigravity-claude-proxy accounts add
antigravity-claude-proxy accounts add --no-browser

The third route is automatic: if you have the Antigravity app installed and logged in, the proxy detects your local session with no extra setup. Once linked, two checks confirm it is working, a health call and an account-limits query:

curl http://localhost:8080/health
curl "http://localhost:8080/account-limits?format=table"

Pointing Claude Code at the proxy

The README offers two ways to configure Claude Code. The web console is recommended: open the WebUI, go to Settings then Claude CLI, use the Connection Mode toggle to switch between Proxy Mode (the local Antigravity-backed proxy) and Paid Mode (the official Anthropic credits, which hides proxy settings to prevent accidental misconfiguration), and click Apply to Claude CLI. The README notes a precedence trap worth remembering: shell environment variables set in something like .zshrc override settings.json, so a variable you exported earlier can quietly win over the console.

Manual configuration edits ~/.claude/settings.json. To use Claude models:

{
  "env": {
    "ANTHROPIC_AUTH_TOKEN": "test",
    "ANTHROPIC_BASE_URL": "http://localhost:8080",
    "ANTHROPIC_MODEL": "claude-opus-4-6-thinking",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-4-6",
    "CLAUDE_CODE_SUBAGENT_MODEL": "claude-sonnet-4-6",
    "ENABLE_EXPERIMENTAL_MCP_CLI": "true"
  }
}

Swapping the model values for names like gemini-3.1-pro-low and gemini-3.5-flash-low points the same setup at Gemini models instead. The auth token is a placeholder because the real authentication is the Google OAuth the proxy holds, not an Anthropic key.

Maturity, testing and the honest bottom line

For an unofficial tool, the project is surprisingly well tested. package.json lists a large suite covering thinking signatures, multi-turn thinking with tools, streaming, interleaved thinking, images, caching, cross-model thinking, no-browser OAuth, empty-response retry and a schema sanitiser. Recent releases are v2.8.6 on 2026-09-06, v2.8.5 on 2026-05-23 and v2.8.4 on 2026-05-14; there is a small mismatch between the tagged version and the version in package.json, so trust the release tag and the installed npm version over the source field.

The honest bottom line returns to the warning. The engineering is solid and the setup is easy, but the model access depends on treating Antigravity's Cloud Code in a way Google may penalise, and the penalty is your account. If you proceed, do it on a burner account, watch account-limits, and treat access as something that could stop at any time. For anyone unwilling to risk a Google account, the official Paid Mode or a normal Anthropic subscription is the safer path the README itself points to.

Editorial conclusion

Use Antigravity Claude Proxy only if you accept the account-ban risk its own README states plainly. Run it with npx, link a burner Google account rather than your main one, point Claude Code at http://localhost:8080 with the provided settings, and check account-limits before relying on it. This is an unofficial tool that may violate Google's Terms of Service.

Frequently asked questions

Official sources

1. badrisnarayanan/antigravity-claude-proxy on GitHub
2. Issues
3. License: MIT
4. README
5. Releases