pi-antigravity-acp-provider

A first-class Pi provider for Google Antigravity through its official ACP server.

Important: this package no longer uses @google/gemini-cli. The Gemini CLI individual Code Assist login path was retired and is not a supported authentication route. Antigravity/agy is the target runtime.

• Registers antigravity-acp/* models backed by Google Antigravity.
• Uses ACP protocol v1 and the official TypeScript SDK.
• Collapses Antigravity's effort-qualified IDs into one entry per model; Pi's Shift+Tab reasoning control selects low/medium/high dynamically.
• Supports Pi streaming, cancellation, usage/quota metadata, lifecycle cleanup, and persisted ACP session restoration across Pi restarts.
• Routes compatible Pi tools through an authenticated loopback MCP bridge; doctor/status names omitted tools and their reasons.
• Supports persisted default, auto-edit, and yolo Antigravity permission modes. The requested default is yolo; switching to a prompting mode retains the single-use, fail-closed Pi permission broker.
• Advertises no ACP filesystem or terminal client capabilities.
• Provides setup, auth-health, logout/account-switching, qualification, quota, and runtime-update commands.
• Automatically checks for newer managed ACP runtimes once per day, with automatic, notify, and manual update modes.
• Uses an Ed25519-signed runtime catalog with exact Google artifact URLs, archive hashes and sizes, strict two-file extraction, pre-activation ACP identity/version validation, immutable releases, rollback retention, musl rejection, macOS quarantine cleanup, and Windows process-tree handling.

Install from the official Pi package gallery/npm:

pi install npm:pi-antigravity-acp-provider
pi

To run from source instead:

git clone https://github.com/zacbemis/pi-antigravity-acp-provider.git
cd pi-antigravity-acp-provider
npm install
pi --no-extensions -e ./extensions/index.ts

In Pi:

1. Optionally run /antigravity-acp setup for a runtime/auth preflight.
2. Run /login.
3. Choose Sign in with an account.
4. Choose Google Antigravity (ACP).
5. If needed, wait for the official ACP server download and extraction. Progress is shown; the Linux build observed during development expands to about 1.8 GB.
6. Complete the Google login in the browser.
7. Run /antigravity-acp setup again to perform a network auth probe and model discovery.
8. Run /model and select one of the antigravity-acp models.
9. Press Shift+Tab to choose the reasoning effort. Only tiers advertised by Antigravity are exposed. A model with a single tier (for example Argon Medium during rollout) remains a reasoning model with that tier; the provider does not invent Low/High variants.
10. Send a prompt. The default permission mode is yolo, so Antigravity-native commands and edits can run without confirmation.

The provider first looks at AGY_ACP_BIN, then its verified managed ~/.local/opt/agy-acp/current/ release, ~/.local/bin/agy_acp_server.par, and PATH. Set AGY_ACP_BIN to explicitly prefer an externally managed runtime. If absent, it installs the platform build published in the ACP registry. A global agy or gemini command is not required.

Loopback MCP traffic is exempted from proxies in the ACP child environment. Explicit HTTP_PROXY, HTTPS_PROXY, ALL_PROXY (and lowercase variants) are preserved. On macOS, when none are explicitly set, the provider probes enabled system HTTP proxy settings to avoid automatic SOCKS selection unsupported by the bundled Python runtime. Set PI_ANTIGRAVITY_ACP_PROXY to an absolute HTTP/HTTPS proxy URL to explicitly override child proxy settings; the provider does not log the override or change its parent environment. Existing NO_PROXY lists and TLS certificate overrides are retained.

Standalone Pi builds also need Node.js to run the ACP supervisor. The provider looks for node or nodejs on PATH; set NODE to the executable path if neither is available. On NixOS with Home Manager, programs.pi-coding-agent.extraPackages = [ pkgs.nodejs ]; adds Node to Pi's PATH. An explicit SSL_CERT_FILE is preserved; otherwise the provider uses NIX_SSL_CERT_FILE or a readable system CA bundle when available.

When Pi is running over SSH, or on Linux without DISPLAY/WAYLAND_DISPLAY, /login automatically uses a manual browser relay:

1. Pi prints the Google authorization URL instead of trying to launch a browser on the server.
2. Open that URL in a browser on your local machine and finish Google sign-in.
3. Google redirects to an Antigravity loopback URL. The page may show a connection error because 127.0.0.1 refers to your local machine; copy the complete final URL from the browser address bar.
4. Paste that URL into Pi. The provider validates its host, port, path, and OAuth state, then relays it to Antigravity's loopback listener on the server. An SSH port-forward is not required.

Set PI_ANTIGRAVITY_ACP_OAUTH_MODE=manual to force this flow, or PI_ANTIGRAVITY_ACP_OAUTH_MODE=browser to force normal browser launch. OAuth URLs and callback codes are kept in a private temporary directory only for the duration of login and are never logged or persisted by this package.

For API-key authentication, choose Enter an API key and then Antigravity Gemini API key in /login, or set GEMINI_API_KEY before starting Pi.

Antigravity owns OAuth tokens under ~/.gemini/antigravity-acp/; Pi stores only a non-secret configured marker. Existing agy CLI credentials and Gemini CLI credentials should not be assumed to authenticate this separate ACP server.

The model catalog comes from the official ACP server. A successful model listing or selection is not an inference/access probe: newly listed models can still fail because of plan eligibility, staged rollout, or backend availability. As of October 13, 2026, Google's Argon announcement and model availability table list Gemini 4 Argon for Google AI Ultra and eligible Enterprise subscriptions, not AI Pro. If it returns Requested entity was not found, check access in the official Antigravity app/CLI with the same account; do not guess alternate model IDs or assume the listing proves access. Use another advertised model while investigating.

On macOS the Antigravity server keeps the consumer token in the login keychain (service gemini, account antigravity-acp) and uses the 0600 file ~/.gemini/antigravity-acp/acp_token.json only when that keychain is unusable. A keychain that is empty while a refreshable token file exists therefore leaves the server with no credentials it can see: every new ACP server process reports Credentials missing or invalid, opens interactive Google consent (which forces the consent screen on every process), and can exceed the session-setup deadline. This provider detects exactly that mismatch and pins the child to the secure-file backend it inspects, so the saved login is reused. Set AGY_ACP_FORCE_FILE_STORAGE yourself to take full control of the choice. doctor/status reports the expected backend as Credential storage (preflight):, since the running server's own functional probe can still fall back to the file store. An explicit GEMINI_HOME relocates the whole tree, including the token file, and is honored by setup, health checks, logout, and the credential-storage decision.

/antigravity-acp setup
/antigravity-acp doctor
/antigravity-acp doctor --verbose
/antigravity-acp status
/antigravity-acp quota
/antigravity-acp update
/antigravity-acp updates [automatic|notify|manual]
/antigravity-acp qualify
/antigravity-acp logout
/antigravity-acp account
/antigravity-acp permissions
/antigravity-acp permissions default
/antigravity-acp permissions auto-edit
/antigravity-acp permissions yolo

Permission and runtime-update modes are saved in $PI_CODING_AGENT_DIR/antigravity-acp-provider/config.json (where PI_CODING_AGENT_DIR defaults to ~/.pi/agent). Runtime updates default to automatic; only provider-managed installations are replaced. ACP session bindings are saved beside the config in sessions.json.

On first use of a custom profile without a config, existing permission/update settings are copied from the default agent directory (or the legacy Gemini-provider config). Existing custom configs are never overwritten, and saved sessions are not copied. Custom Pi profiles do not isolate Antigravity accounts or managed runtimes: Antigravity's OAuth credentials and runtime installation remain in their shared locations.

logout/account clears local Antigravity credentials and saved ACP sessions. Run Pi's /logout afterward to remove the Pi credential marker, then /login for the new account. update checks the official registry and installs its newest release only after matching it to the provider's signed runtime catalog. See docs/RUNTIME-UPDATES.md.

npm run check
npm run test:real-acp  # initializes the installed Antigravity ACP server
npm run test:live      # sends a real authenticated prompt
npm run test:qualify   # live cancel, restore, MCP, model, and permission qualification
npm run test:packed
npm audit --audit-level=moderate

# Maintainer-only runtime catalog refresh/signing
npm run refresh:runtime-manifest
ACP_RUNTIME_MANIFEST_PRIVATE_KEY_PATH=/secure/key.pem npm run sign:runtime-manifest

CI checks Node 22.19.0 and 24, including typechecking, unit tests, packed installation and the full dependency audit. Live authenticated tests are opt-in and are not part of PR CI. See docs/MAINTENANCE.md for update and release policy.

Prompts are bounded by inactivity, not total turn duration: streaming progress resets a 10-minute idle window. An outstanding native tool, parked Pi tool, or permission request gets a finite 60-minute no-progress window instead, so long work survives the former two-minute Pi-tool deadline without making stuck tools wait forever. Cancellation still sends session/cancel, answers parked requests, and closes an unresponsive agent after its 1.5-second grace period. The interactive permission broker retains its two-minute response limit. Integrations can override promptIdleTimeoutMs and promptWorkIdleTimeoutMs in connection options with positive finite durations; initialize/auth/session-setup deadlines are unchanged.

System instructions are kept outside truncated conversation history. Instructions larger than 256 KiB UTF-8 fail clearly rather than being silently shortened. ACP has no mid-prompt system-update RPC: an instruction change received with tool/permission results finishes the existing prompt under its original instructions, then forces reconstruction before the next prompt. Such a stale binding is not persisted for restoration.

This launches a full coding agent with the user's OS privileges. The default yolo mode permits Antigravity-native commands and edits without confirmation. Use /antigravity-acp permissions default for confirmation prompts. Disabling ACP filesystem/terminal client callbacks is not a sandbox for Antigravity-native tools. Pi hooks govern tools routed through the pi_ MCP namespace; Antigravity-native tools remain governed by Antigravity policy and ACP permission requests. New/restored sessions must advertise and confirm the requested permission mode. Unsupported or failed mode changes close affected sessions; an executing turn is stopped before changing its policy. Unexpected mode-change notifications also invalidate the session. Doctor/status distinguishes requested policy from each live binding's confirmed mode. This protocol enforcement is not a sandbox.

This release requires Pi 1.1.x and Node.js 22.19.0 or newer; development is pinned to Pi 1.1.0, ACP SDK 1.8.0, and ACP protocol 1. The provider supports stable session configuration options and retains compatibility with older Antigravity model-selection metadata; it does not enable experimental ACP v2. Upgrade Pi before upgrading from provider 0.1.12. Pi supplies the host packages at runtime, so their peer ranges remain * as required by Pi's package contract; this is not a promise of compatibility with every Pi version. Transcript system instructions and tool additions/removals are replayed into ACP checkpoints, replacing stale warm sessions when that state changes. The bundled signed catalog bootstraps Antigravity ACP 1.1.1 and can accept newer signed catalog releases without an npm update. ACP session setup allows up to two minutes for slow first-run initialization, while transport shutdown rejects pending requests immediately. The current official registry and signed catalog provide Linux x64/ARM64, Windows x64/ARM64, and macOS Intel/ARM64 artifacts. Intel macOS artifacts exist, but the proposed local re-signing workaround is not enabled or qualified by this package. Alpine/musl is rejected because Google's Linux build targets glibc.

During browser authentication, Chromium may write Opening in existing browser session. to the ACP process's inherited stdout. The transport ignores only that exact known compatibility line and reports its count in doctor; all other non-JSON stdout remains a fatal protocol error.

Managed installations also repair executable permissions for both the ACP server and its localharness_external helper. This repairs installations created by 0.1.3 and earlier, where OAuth could succeed but session creation failed with an opaque ACP Internal error because the extracted helper was not executable.

Earlier repository documents analyzing @google/gemini-cli@0.58.0 describe the superseded implementation and are retained only as historical research. See docs/ANTIGRAVITY-MIGRATION.md.

MIT