@heyhuynhgiabuu/pi-oauth-antigravity

Google Antigravity OAuth provider extension for Pi. Connects Pi directly to Google Cloud Code Assist / Antigravity with zero-friction OAuth login, day-one support for Gemini 3.8 Flash, prompt-cache session affinity, and image generation.

Features

• Google OAuth Login: Browser-based PKCE flow with local loopback callback (localhost:51121) and headless paste-URL fallback. Automatically handles token refresh with AbortSignal forwarding.
• Day-One Gemini 3.8 Flash: First-class support for gemini-3.8-flash with dynamic effort-tier routing (-low, -medium, -high), 65,536 max output token clamping, and fallback resilience.
• Prompt Cache Affinity & Trajectory Chaining:
  • Deterministic 63-bit session IDs derived from initial turn content.
  • Monotonic trajectory tracking (agentId, trajectoryId, stepIndex).
  • Response ID chaining via labels.last_execution_id.
  • Endpoint stickiness to prevent cluster hopping across Google's daily and fallback endpoints.
  • Cross-restart session state persistence (.pi/agent/cache/antigravity-sessions.json) to maintain cluster affinity across quick Pi restarts.
• Image Generation: Built-in generate_image tool and /antigravity.image command powered by Google's image models with aspect-ratio selection and safe directory containment.
• Diagnostic & Usage Tools:
  • /antigravity.usage — token counts, cache read efficiency, and session metrics.
  • /antigravity.models — backend discovery of available Cloud Code Assist models.
  • /antigravity.doctor — connection check, token expiry inspection, and diagnostic dump.

Supported Models

| Public Model ID | Backend Wire ID | Max Output | Context Window | | :--- | :--- | :--- | :--- | | antigravity/gemini-3.8-flash | gemini-3.8-flash-{low,medium,high} | 65,536 | 1,048,576 | | antigravity/gemini-3.7-flash | gemini-3.7-flash-{low,medium,high} | 65,536 | 1,048,576 | | antigravity/gemini-3.7-flash-thinking | gemini-3.7-flash-thinking | 65,536 | 1,048,576 | | antigravity/gemini-3.6-flash | gemini-3.6-flash-{low,medium,high} | 65,536 | 1,048,576 | | antigravity/gemini-3.1-pro | gemini-3.1-pro | 65,536 | 1,048,576 | | antigravity/claude-sonnet-4-6 | claude-sonnet-4-6 | 64,000 | 200,000 | | antigravity/claude-opus-4-6 | claude-opus-4-6 | 64,000 | 200,000 | | antigravity/gpt-oss-120b | gpt-oss-120b | 8,192 | 131,072 |

Installation

Install directly into Pi via npm:

pi install npm:@heyhuynhgiabuu/pi-oauth-antigravity

Or run directly from source:

pi -e /path/to/pi-oauth-antigravity/dist/index.js

Setup & Login

1. Run Pi and start the OAuth login:

   pi auth login --provider antigravity

2. Your browser will open the Google Sign-In page. Sign in with your Google account.
3. Once authenticated, the extension saves credentials and discovers your available Cloud Code Assist project.
4. Select or switch to any Antigravity model:

   pi --model antigravity/gemini-3.8-flash

Slash Commands

• /antigravity.usage — View current session usage, cached token statistics, and cost estimates.
• /antigravity.models — List dynamically fetched and statically registered models.
• /antigravity.doctor — Diagnose OAuth state, refresh token health, and endpoint connectivity.
• /antigravity.image <prompt> [--aspect 1:1|16:9|...] — Generate images directly to your project.

Development

# Install dependencies
npm install

# Run unit tests (50 tests)
npm test

# Typecheck
npm run typecheck

# Build TypeScript to dist/
npm run build

Credits & Upstream

Vendored and adapted from Rahularya01/pi-antigravity (MIT License) with prompt-cache session affinity, day-one Gemini 3.8 Flash catalog, response chaining, and cross-process persistence.

License

MIT © 2026 huynhgiabuu