Antigravity + Gemini CLI OAuth Plugin for Opencode

Enable Opencode to authenticate against Antigravity (Google's IDE) via OAuth so you can use Antigravity rate limits and access models like gemini-3.1-pro and claude-opus-4-6-thinking with your Google credentials.

Unofficial plugin. Google may restrict accounts using third-party clients.

Setup

Requires OpenCode 2.1.2+ and Node.js 20+.

Add to ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "plugins": ["opencode-antigravity-auth@2.1.2"]
}

Then run:

opencode auth login google

Choose Google OAuth (Antigravity). Existing accounts are reused.

To use a local checkout, run npm ci && npm run build and replace the package name above with the checkout's absolute path.

Use

opencode models
opencode run --model=google/antigravity-gemini-3.8-flash-high "Hello"
opencode run --model=google/antigravity-claude-opus-4-6-thinking#max "Hello"

Models are discovered from your enabled accounts and cached for an hour. Availability depends on your Google plan. Select an antigravity-* model for Google OAuth. Native Google API-key models are hidden while Antigravity OAuth is selected and return when you switch to an API-key connection.

Inside OpenCode, open /antigravity (or /ag) to:

• See logged-in accounts, the current selection, and cached quota percentages and reset times.
• Switch to an enabled account by selecting its row.
• Check Antigravity and Gemini CLI quotas and reset times.
• Add an account, or use Manage account… to verify, enable, disable, re-authenticate, or delete one.
• Refresh the model list.

The account list shows the lowest cached quota across Claude, Gemini Pro, and Gemini Flash. Choose Check quotas / verify enabled accounts to refresh the saved quota data. Refresh quotas if an older cache shows a percentage without a reset time.

Accounts are stored in ~/.config/opencode/antigravity-accounts.json. Back up this file before moving machines; it contains credentials. Disabling an account excludes it from rotation and routine quota checks.

Development

npm ci
npm run typecheck
npm test
npm run build
OPENCODE_BIN=/path/to/opencode npm run test:e2e:v2

The runtime test uses synthetic credentials. Authenticated model and menu checks require a logged-in Google account.

V2 migration and verification · Configuration · Troubleshooting

OpenCode 1.18.29+ remains supported through the legacy entrypoint; its account menu opens from opencode auth login.