Google Antigravity

Brainwrite connects to Google Antigravity through Google's official Agent Client Protocol server. It does not ask for your Google password or copy a login from another app.

Set up

1. Choose an Antigravity model in the model picker.
2. Select Install official Antigravity. The download comes from dl.google.com and Brainwrite verifies its pinned size and SHA-256 before installing it.
3. Select Sign in with Google and finish in your browser.
4. Return to Brainwrite, open the model picker, and select Refresh. The account's available models appear after discovery completes.

The runtime download is large because Google ships the ACP server and its local computer harness together. Brainwrite stores it in its own data directory; it does not modify a system installation.

After upgrading from the older agy integration

Version 0.1.51 switched from the community agy CLI to Google's official ACP runtime. An existing Antigravity app or agy login does not sign this separate runtime in. Complete Install official Antigravity and Sign in with Google in the model picker, then refresh and choose a model available to that account.

Saved legacy agy paths, including Windows .cmd shims, now resolve to the official runtime. Genuine custom ACP executable paths are still respected. The migration does not copy credentials from another app, remove the old CLI, or change which Google account you authorize.

The Google sign-in belongs to the engine instance, not the runtime version, so ordinary app updates do not require signing in again. Cold starts can be slow, particularly on Windows; setup and model discovery allow up to 90 seconds. If Google expires or revokes the saved session, sign in again when prompted.

Multiple Google accounts

Create another Antigravity engine instance for another account. Each instance has a separate private GEMINI_HOME, token, settings file, and model catalog. Signing one instance in never replaces another instance's account.

Remote servers

When the Brainwrite server and browser are on different computers, Google's final redirect points to the server's loopback address and may show a page that cannot load locally. Expand Signing in from another computer?, copy the complete redirect URL from the browser address bar, and paste it into Brainwrite. The server accepts only the loopback port and OAuth state created by that exact in-progress sign-in.

Permissions and tools

Antigravity uses the same Brainwrite approval cards as other ACP engines. Connected apps, custom MCP servers, the browser, computers, and teammate tools are mounted only for the active session; Brainwrite no longer edits the user's global Gemini MCP configuration.

The normal mode asks before protected actions. Full access maps to Antigravity's native yolo mode, but native questions still wait for a person instead of being guessed automatically.