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Antigravity CLI (agy) is Google’s coding agent for the terminal. Connected to Kylon, it runs on your computer with your own Antigravity sign-in, files, and repositories, and joins the workspace as an Agent. In the New agent dialog it reads: “Runs on your computer and uses your model provider’s tokens.” Pick it when you already work with Antigravity CLI, or want an Agent that uses your Google account’s Antigravity quota instead of Kylon credits.
Antigravity CLI is available to all workspaces. If it is missing from How it runs, or shows Coming soon under Invite your agent, it is not open in your workspace yet. Choose it under Invite your agent and send the request so the Kylon team knows you want it.

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Before you start

  • A computer running macOS, Windows, or Linux, on x64 or arm64, that stays on and awake while the Agent should answer.
  • Antigravity CLI installed. If agy --version does not answer, install it with Google’s installer, then open a new terminal:
  • Antigravity CLI signed in on that computer. Run agy once in a terminal and finish the Google sign-in, then quit. Kylon’s turns reuse that sign-in. See Google’s Authenticate guide for the sign-in options.
  • Node.js 22.15 or newer, so the connection prompt can run the Kylon CLI with npx. If Node.js is missing on macOS or Linux, the setup guide installs the Kylon CLI with its own Node runtime instead.

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Connect it

1

Open New agent

In Chat, open the + menu at the top of the sidebar and choose New agent. You can also open Members, choose +, and pick New agent.
2

Name the Agent and choose Antigravity CLI

Enter a Name, keep the generated avatar or choose Try another, and add a Specialty if you like. Under How it runs, choose Antigravity CLI, then choose Next.The runtime cannot be changed after the Agent is created.
3

Copy the prompt

Kylon shows Connect Antigravity CLI with a connection prompt. Choose Copy prompt. Keep this dialog open: leaving it cancels setup.The prompt holds a one-time connection link that expires 30 minutes after you copy it. Paste it only into your own Antigravity CLI session.
4

Paste it into Antigravity CLI

Start agy on the computer where the Agent should run and paste the whole prompt. Unlike most providers, this prompt carries the full connection command. Antigravity CLI checks the Kylon CLI and its background service, upgrades them if they are older than required, runs kylon agent link, and starts the service.Approve the command when it asks. It downloads the Kylon CLI, writes under ~/.kylon, and registers a background service for your user account. The command can print nothing for two to three minutes while it downloads and checks the computer.
5

Let Kylon install the Antigravity ACP server

Kylon starts Antigravity CLI through Google’s Antigravity ACP server, a separate download from agy that Kylon pins and verifies. If the setup reports it missing, run this with the Kylon CLI on that computer (not through npx):
If kylon is not on your PATH yet, use ~/.kylon/bin/kylon (%USERPROFILE%\.kylon\bin\kylon.cmd on Windows).
6

Add the Agent to a Room

When the link succeeds, the dialog updates on its own and Kylon creates the Agent. It starts private, with no access to existing Rooms. Message it directly, or add it to a Room and @mention it there. See Agent access.

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Check the connection

  • The Agent’s profile shows Online while the computer is connected. It shows Checking sign-in until the Agent’s first successful turn confirms the Antigravity sign-in.
  • If the dialog or profile says Sign in to Antigravity CLI (Connected · Sign-in needed), the computer is linked but agy is not signed in. Run the command Kylon shows on that computer, then send the Agent a message.
  • On the computer, kylon gateway status shows the background service running with this Agent listed.
  • To confirm the sign-in by hand, agy -p "/usage" --output-format json must print your quota without asking for anything.

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Usage and billing

Model usage goes to the Antigravity account you signed in with on that computer. Agents that run on your own computer do not need Kylon workspace credits to reply.

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Limits

  • The Agent answers only while the computer is on, awake, and online. The background service keeps running after the terminal session ends.
  • Kylon needs Antigravity ACP server 1.4.3 or newer, the release Kylon pins. kylon provider install antigravity keeps only the release that your installed Kylon CLI pins.
  • Run setup as your normal user account. Do not use sudo or a service account, and on macOS do not connect over SSH.

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Troubleshooting

If Kylon still shows the Agent as not connected two minutes after setup finishes, run kylon diagnose --upload and share the report it prints with the Kylon team.