Configure Antigravity

Install

Use the agent image to make agy available in a local container. In a cloud sandbox, Outpost installs it when it is missing, unless you set bootstrap: false.

The installer supports Linux amd64 and arm64 (glibc and musl) and macOS Intel and Apple Silicon. Other platforms fail.

Check the installed version against the pinned one:

npx outpost doctor --agent antigravity --image outpost:dev
npx outpost doctor --agent antigravity --sandbox-provider local

• Pinned versionagentVersions.antigravity, downloaded from Google’s versioned archives.
• SHA-512 checkEach archive is verified before extraction; a mismatch aborts the installation.
• No auto-updateImages, runs and doctor set AGY_CLI_DISABLE_AUTO_UPDATE=true.

doctor warns when the versions differ. It does not verify the binary’s checksum or test sign-in.

Sign in with your account

Run agy on the host and sign in with your Google account.

import { createAgent, createAntigravityHarness } from "@elie-laloum/outpost";

export const coder = createAgent({
  harness: createAntigravityHarness({ authentication: "account" }),
});

Outpost copies ~/.gemini/antigravity-cli/antigravity-oauth-token into the sandbox’s private home. For a token stored elsewhere, pass { account: { file: "/path/to/token" } }. See Authentication.

Use an API key

Declare GEMINI_API_KEY. Gemini API usage is billed separately from Google AI plans.

import { createAgent, createAntigravityHarness } from "@elie-laloum/outpost";

export const coder = createAgent({
  harness: createAntigravityHarness({
    authentication: "usage",
    variables: { GEMINI_API_KEY: process.env.GEMINI_API_KEY ?? "" },
  }),
});

Outpost also writes ~/.gemini/antigravity-cli/settings.json in the sandbox home to select the Gemini provider. { usage: { variable: "NAME" } } reads the key from another declared variable.

Available features

• ConversationsResume in the same sandbox session with sandbox.resume(id, options) or a warm result’s resume().
• Response repairsAn invalid typed answer is repaired in that same conversation.
• SteeringDelivered as resumed: Outpost stops agy, then resumes the conversation with your text.
• MCP serversMerged into ~/.gemini/config/mcp_config.json in the agent home.
• UsageInput, cached and output tokens per turn; thinking tokens count as output.
• Model and modeThe agent’s model becomes --model; mode sets --mode accept-edits or plan.

Without mode, headless runs pass --dangerously-skip-permissions: the sandbox bounds what the agent can do. Interactive terminals keep the CLI’s approval prompts. Choose an agent compares every agent.

Limits

• Conversations are not captured: they end with the sandbox. Cold resume and fork() are rejected, and createAntigravityHarness() refuses a conversations store.
• A model with reasoning or maxOutputTokens is rejected when the agent is composed.
• MCP tools.include, startupTimeoutMs and oauth: "login" are refused.
• Bootstrap reuses an agy already on the path without checking its version or checksum.

API: createAntigravityHarness · AntigravitySettings · agentVersions.