How to add a status line to Antigravity CLI

Antigravity CLI (agy) can run a command of your choice to draw its status bar. You set it under statusLine in ~/.gemini/antigravity-cli/settings.json; agy runs it on every refresh, pipes the session as JSON on its standard input, and shows what it prints. The quickest way to set one up is npx agy-powerline init, then one restart of agy.

• The one-command setup
• The statusLine setting
• What the command receives
• Write your own status line
• Check that it works

The one-command setup

You need Node.js 20 or newer and agy.

npx agy-powerline init

init copies the status line script to ~/.agy-powerline, adds the statusLine entry to agy's settings.json, and asks for a preset, a layout and a theme with a preview of each. It asks before replacing anything and keeps a backup of settings.json. Restart agy once so it reads the new setting. What init does covers every step.

From inside agy you can also install agy-powerline as a plugin and let its setup skill run init for you (Install from inside agy).

The statusLine setting

statusLine takes a type of command and the command to run. Use absolute paths: agy does not expand ~.

{
  "statusLine": {
    "type": "command",
    "command": "'/usr/bin/node' '/home/you/.agy-powerline/statusline.js'"
  }
}

• macOS and Linux: the command runs through sh -c, so quote paths that may contain spaces.
• Windows: agy runs the command through cmd /c. Point it at a .cmd file and don't put quotes around the path: "command": "C:/Users/you/.agy-powerline/statusline.cmd".
• Inside agy: /statusline <command> sets it, and /statusline reset goes back to the built-in bar.

init can also keep agy's own bar and draw below it (--stack), or leave blank lines above (--padding <n>). The exact commands for each system are in Setting it up by hand.

What the command receives

On every refresh the command gets one JSON object on stdin: the model, the context window, quotas, the folder, the agent's state, the terminal width and more. For example:

{
  "model": { "id": "Gemini 3.8 Flash (High)", "display_name": "Gemini 3.8 Flash (High)" },
  "context_window": { "context_window_size": 1048576, "used_percentage": 10.42 },
  "quota": {
    "gemini-5h": { "remaining_fraction": 0.979, "reset_in_seconds": 17042 }
  },
  "terminal_width": 198
}

Every field seen so far, with types and examples, is in the payload reference.

Write your own status line

Any program that reads stdin and prints text works. A minimal one in Node.js:

let input = "";
process.stdin.on("data", (chunk) => (input += chunk));
process.stdin.on("end", () => {
  const data = JSON.parse(input || "{}");
  const left = data.quota?.["gemini-5h"]?.remaining_fraction;
  const quota = typeof left === "number" ? ` · 5h ${Math.round(left * 100)}% left` : "";
  console.log(`${data.model?.display_name ?? "agy"}${quota}`);
});

Things to plan for, since agy runs it on every refresh:

• Treat every field as optional. A field for something that isn't happening is often missing rather than empty.
• Exit quickly and never crash. Print something short (or nothing) on bad input instead of a stack trace.
• Don't print raw text from the payload. Branch names and titles can contain terminal control characters; strip them first.
• Keep it fast. A status line that starts other programs on every refresh slows agy down; cache what you can.

agy-powerline does all of this, with themes, layouts and an editor, if you'd rather not write your own.

Check that it works

npx agy-powerline doctor

doctor checks the install, runs the configured command with sample JSON and shows its output and timing. To see a bar without agy, run npx agy-powerline render --demo. If the bar doesn't show up, see Troubleshooting.