Antigravity Auth

Google Antigravity OAuth for coding agents. Authenticate with your Google account and access Gemini 3 and Claude 4.6 models through Antigravity's endpoints.

This is a monorepo publishing three packages:

Package	Description
@cortexkit/opencode-antigravity-auth	OpenCode plugin — intercepts fetch() and transforms requests to the Antigravity format. Multi-account rotation, quota handling, session recovery.
@cortexkit/pi-antigravity-auth	pi extension — registers a custom provider with OAuth login and a Gemini streaming implementation.
@cortexkit/antigravity-auth-core	Harness-agnostic core: OAuth, raw HTTP/1.1 transport, device fingerprint, request transforms, model registry, managed-project resolution. Shared by both harnesses.

Caution

Using this software (and any proxy for Antigravity) violates Google's Terms of Service. Accounts may be suspended or banned. This is an unofficial tool not endorsed by Google; you assume all risks.

Installation

OpenCode — add to ~/.config/opencode/opencode.json:

{
  "plugin": ["@cortexkit/opencode-antigravity-auth@latest"]
}

See the OpenCode package README for model configuration, login, and troubleshooting.

pi — install the extension package:

pi package add @cortexkit/pi-antigravity-auth

Then /login google-antigravity. See the pi package README.

Development

npm install         # install workspace dependencies
npm run build       # build core, then opencode + pi
npm run typecheck   # typecheck all packages
npm test            # run all package test suites

Releasing

Releases are tag-driven. scripts/release.sh <version> runs checks, syncs all package versions (scripts/version-sync.mjs), commits, tags v<version>, and pushes. The Release workflow then publishes all three packages to npm via trusted publishing.

./scripts/release.sh 1.0.0          # release
./scripts/release.sh 1.0.0 --dry    # preview

License

MIT