Browser-in-the-Loop Agents

Antigravity agents can control a Chrome browser directly. They navigate pages, click elements, fill forms, take screenshots, and inspect the DOM and console output. For frontend development, this means an agent can build a UI, test it in a real browser, see what's broken, and fix it — all without you opening a browser yourself.

What you'll learn

• Browser-in-the-loop agents use Chrome DevTools Protocol to interact with web pages
• They can navigate, click, type, take screenshots, and read console output
• This enables agents to do frontend development, visual testing, and debugging autonomously

Build it

Build a login form component with email, password, and submit button.
After writing the code, open it in the browser, fill in the fields,
click submit, and verify the form validates empty fields correctly.
If anything doesn't work, fix it and test again.

The agent:

1. Writes the component code
2. Starts a dev server
3. Opens Chrome to the dev server URL
4. Fills in the form fields
5. Clicks submit
6. Reads the validation error messages from the DOM
7. Checks the console for JavaScript errors
8. Fixes any issues and repeats

What goes wrong

Mistake	How you notice it	The fix
Browser not available	Agent reports "Chrome not found"	Install Chrome or Chromium. On headless servers, use --headless
Dynamic content not loaded	Agent reads page before JavaScript renders	Add explicit wait instructions: "Wait for the page to fully load before checking"

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