Use Gemini through a Google Antigravity sign-in, as a native Godwit plugin. The design and its risks are in Godwit's ADR 0033.
Read this first. Antigravity's terms forbid reaching the service through third-party software, and Google can suspend your Antigravity and Gemini CLI access for it. Google stores what you send, and its reviewers may read it: here, that is your mail. A Gemini API key under Godwit's model settings is the supported way. Godwit's plugin directory lists it with this warning; it needs Godwit 1.30.0 or later.
macOS only: elsewhere Google's server keeps its token in a plain file.
- Godwit's SDK talks OpenAI chat to a loopback server in the plugin. Each request becomes one session on Google's ACP server, with the whole history.
- The agent's own tools are off (
enabledTools: []). If it tries one anyway, the turn stops and the request fails. - A tool the model calls is not run here: the agent's permission request becomes
tool_calls, the turn is cancelled, and Godwit handles the call with its usual approvals. - The server's copies of each session are deleted after the turn, since they hold mail.
- The token stays in the macOS keychain, where Google's server keeps it. The plugin never reads it.
python3 scripts/package.pyThen in Godwit: Settings → Extensions → install from a folder, and pick dist/antigravity.
Bump version in plugin.json, merge, and push the tag v<version>. CI tests, builds both macOS libraries and publishes them as a GitHub release. Then add the release, with each file's URL, size and SHA-256, to godwit-plugin.json (keep the older releases), and open a pull request in godwit-email/plugins that points the entry's source.sha at that commit.
Run the probe from ADR 0033 again against the new version. If enabledTools: [] no longer turns the built-in tools off, do not ship it.
The plugin is Apache-2.0. Google's server is proprietary, and is downloaded from Google at sign-in, not redistributed.