pi-agy

pi-agy is a Pi Coding Agent provider that lets Pi talk directly to Google Antigravity / Cloud Code Assist models — Gemini, plus the Claude and GPT-OSS models Antigravity also advertises. Sign in with Google, pick a model, and go. Under the hood it handles OAuth login, native streaming, model routing, quota diagnostics, and optional multi-account failover itself, so it never shells out to an external Antigravity CLI.

Unofficial integration. This project is not affiliated with or endorsed by Google. Use it only with an account and services you are authorized to access, and review its source before granting OAuth permissions.

Contents

• Requirements
• Install
• Quick start
• Authentication and credential safety
• Commands
• Models and routing
• Configuration
• Troubleshooting
• Development

Requirements

• Pi Coding Agent and Pi AI version 0.80.0 or later
• A Google account that can use the relevant Cloud Code Assist / Antigravity services
• A browser to complete the Google sign-in. Same-machine is best (the browser hits the local callback automatically); on a remote/headless machine, complete sign-in anywhere and paste the resulting callback URL back into Pi (see Troubleshooting).

Install

Install directly from npm:

pi install npm:pi-agy

Restart Pi (or run /reload) after installation. To update the npm package later, use pi update npm:pi-agy.

Quick start

1. Start Pi and run /login antigravity to link your Google account.

2. To link additional accounts for automatic quota failover, run /login antigravity or /antigravity and choose ➕ Add new account.

3. Manage linked accounts, switch active preference, or check quotas across all accounts with /antigravity or /antigravity.accounts.

4. Select a model, for example:

   /model antigravity/gemini-3.7-flash
   

5. Start working. If the active account returns HTTP 429, the provider tries each linked account in order and keeps using the first successful one. If a request fails, run /antigravity.doctor for sanitized diagnostics.

Authentication and credential safety

The provider uses the OAuth 2.0 Authorization Code flow with PKCE, so credentials are only ever exchanged with Google — never typed into Pi.

1. /login antigravity opens Google sign-in (or the account management menu if already logged in) and starts a temporary callback listener at http://localhost:51121/oauth-callback.
2. After you approve access, Pi exchanges the callback code for tokens and stores the provider credentials in Pi's auth store (normally ~/.pi/agent/auth.json).
3. Pi refreshes access tokens automatically when they expire — you shouldn't need to sign in again unless a token is revoked.

Each linked account is stored under a dedicated key in auth.json (antigravity for account 1, antigravity-2 through antigravity-10 for additional slots). Automatic switching occurs seamlessly on pre-stream HTTP 429 quota exhaustion.

The callback listener binds only to a loopback host, so it isn't reachable from outside your machine. The auth file it writes to contains sensitive access and refresh tokens: do not commit it, paste it into issues, or share its contents.

Signing in requests these Google OAuth scopes:

Scope	Why it's needed
aicode	Access to the Cloud Code Assist / Antigravity model catalog and endpoints
cloud-platform	General Cloud Code Assist API access
userinfo.email, userinfo.profile	Identify the signed-in Google account
cclog	Cloud Code Assist logging/telemetry endpoints used by the API
experimentsandconfigs	Server-side experiment and config flags for the API

Review these permissions before approving access. If your credentials expire or are revoked, just re-run /login antigravity to sign in again.

Commands

Command	Description
/login antigravity	Sign in or open interactive account management (add, switch, quotas, remove).
/model antigravity/<model-id>	Choose a registered Antigravity model.
/antigravity	Open interactive Antigravity account manager dashboard.
/antigravity.accounts	Open interactive Antigravity account manager dashboard.
/antigravity.doctor	Show sanitized provider diagnostics, including the endpoint, status, and resolved runtime model.

Model availability, entitlement, quota groups, and resets are returned by the service and can differ by account. The quota percentage shown for a model can represent a shared pool, not a private per-model allowance.

Models and routing

The static model IDs registered by this extension match the Antigravity CLI catalog (agy models). Use /antigravity.models to see live availability and quota for your account — the table below is a reference for what each public model ID maps to.

agy models advertises display entries across Gemini Flash (3.7, 3.6, 3.5), Gemini Pro, Claude Sonnet/Opus Thinking, and GPT-OSS Medium. Pi collapses those into seven public model IDs, each showing only the thinking level(s) that model advertises.

Why Claude and GPT-OSS appear

Antigravity / Cloud Code Assist exposes a multi-provider catalog. Depending on your account, its Google-authenticated API can advertise Google Gemini models alongside Claude models served through Anthropic Vertex and GPT-OSS served through OpenAI Vertex. This extension intentionally exposes those advertised Claude and GPT-OSS models through the single antigravity provider; they are not separate Pi providers and do not use a separate Anthropic or OpenAI login.

The backend's display labels do not always match its runtime IDs. For example, gemini-3.5-flash-extra-low, gemini-3.5-flash-low, and gemini-3-flash-agent can be displayed as Gemini 3.5 Flash Low, Medium, and High. Gemini 3.7 Flash uses the single gemini-3.7-flash-tiered runtime and receives Low, Medium, or High through generationConfig.thinkingConfig; Gemini 3.6 Flash still uses separate effort-specific runtime IDs.

Public model ID	Input	Thinking levels shown	Max output tokens	Request routing
gemini-3.7-flash	Text, image	Low, Medium, High	65,536	gemini-3.7-flash-tiered + thinkingLevel Low/Medium/High
gemini-3.6-flash	Text, image	Low, Medium, High	65,536	low → gemini-3.6-flash-low; medium → gemini-3.6-flash-medium; high → gemini-3.6-flash-high
gemini-3.5-flash	Text, image	Low, Medium, High	65,536	low → gemini-3.5-flash-low; medium → gemini-3.5-flash-low; high → gemini-3-flash-agent
gemini-3.1-pro	Text, image	Low, High	65,535	low → gemini-3.1-pro-low; high → gemini-pro-agent
claude-sonnet-4-6	Text, image	High	64,000	high → claude-sonnet-4-6
claude-opus-4-6	Text, image	High	64,000	high → claude-opus-4-6-thinking
gpt-oss-120b	Text	Medium	32,768	medium → gpt-oss-120b-medium

To limit which models Pi cycles through, enable specific entries in ~/.pi/agent/settings.json:

{
  "models": {
    "antigravity/gemini-3.7-flash": { "enabled": true },
    "antigravity/gemini-3.6-flash": { "enabled": true },
    "antigravity/gemini-3.5-flash": { "enabled": true },
    "antigravity/gemini-3.1-pro": { "enabled": true },
    "antigravity/claude-sonnet-4-6": { "enabled": true }
  }
}

Configuration

All primary environment variables start with ANTIGRAVITY_. The legacy NOAGY_ prefix is also accepted for compatibility.

Variable	Purpose
ANTIGRAVITY_BASE_URL	Override the API base URL. It must be HTTPS, contain no URL credentials, and target an allowed Google APIs host.
ANTIGRAVITY_PROJECT_ID	Use a specific Cloud Code Assist project ID instead of discovery or the stable account fallback.
ANTIGRAVITY_CALLBACK_HOST	Bind OAuth callback to 127.0.0.1, ::1, or localhost only. Defaults to 127.0.0.1.
ANTIGRAVITY_USER_AGENT	Override the request user-agent.
ANTIGRAVITY_RUNTIME_MODEL	Pin requests to a runtime model ID, bypassing normal static routing.
ANTIGRAVITY_CLIENT_ID	Use a custom Google OAuth client ID.
ANTIGRAVITY_CLIENT_SECRET	Use a custom Google OAuth client secret. Keep it out of source control and shell history.
ANTIGRAVITY_NO_KEEPALIVE	Set to 1 to disable the long-lived keep-alive connection pool and use Node's fetch defaults.
ANTIGRAVITY_NO_PREWARM	Set to 1 to skip the TLS pre-warm request made when the extension loads.
ANTIGRAVITY_HTTP2	Set to 1 to negotiate HTTP/2 for API requests. Off by default.

By default, the provider tries https://cloudcode-pa.googleapis.com and then its Google sandbox fallback if necessary. Prefer the built-in OAuth client unless you have a reason to use your own credentials.

Latency

Provider requests reuse a long-lived keep-alive connection pool, so consecutive turns do not repeat the DNS, TCP, and TLS handshake. The pool is scoped to this provider and does not change HTTP behaviour elsewhere in Pi. When HTTP_PROXY, HTTPS_PROXY, or ALL_PROXY is configured, requests instead use Pi's global proxy-aware dispatcher. The connection is also opened when the extension loads so the first message of a session skips the handshake too. For the lowest time-to-first-token, pick a fast runtime: gemini-3.7-flash with reasoning off routes to gemini-3.7-flash-tiered at thinking level LOW. Setting ANTIGRAVITY_PROJECT_ID also removes the project-discovery round-trip when credentials do not already carry a project ID.

Troubleshooting

• No credentials / 401 / 403: Run /login antigravity again, then check /antigravity.doctor.
• Remote/headless machine — browser can't reach localhost:51121: The callback binds to loopback only, so a browser on another machine can't hit it. You have two options:
  • Paste (no extra setup): Run /login antigravity, open the shown URL and complete Google sign-in in any browser. When it redirects to http://localhost:51121/oauth-callback?… and fails to load, copy that full URL from the address bar and paste it into the prompt Pi shows. The code is single-use and expires quickly, so paste promptly.
  • SSH tunnel (reusable): From the machine with the browser, run ssh -N -L 51121:127.0.0.1:51121 <user>@<server> and keep it open, then run /login antigravity on the server. The redirect to localhost:51121 tunnels through to the local callback automatically.
• OAuth callback will not start: Ensure port 51121 is free and ANTIGRAVITY_CALLBACK_HOST is a permitted loopback address.
• Model is unavailable: Run /antigravity.models; availability is account- and service-dependent.
• Claude/GPT tool-call schema error: Upgrade to the latest package release. The provider adapts Pi's JSON Schema tool definitions for the Cloud Code Assist custom-tool bridge.
• Quota or rate limit: Run /antigravity.usage. A pre-stream 429 automatically advances through the linked account pool. If every linked account is limited, the final 429 is returned normally. Changing models may still draw from the same account-level shared pool.
• An account is not used: Run /antigravity.accounts and use the login command shown beside an empty slot. Logging in repeatedly with the same provider ID replaces that slot; use a different numbered ID for each Google account.
• Need a safe diagnostic: /antigravity.doctor redacts recognized secrets from its error output. Still review output before sharing it publicly.

Development

npm install
npm run check

The package declares its Pi extension in package.json under pi.extensions. See the Pi package documentation for package installation, manifest, and gallery conventions.

License

MIT