Browser command (/browser)

Hand a web task to the built-in browser subagent, which drives Google Chrome to navigate pages, interact with your running app, inspect the console and network, and capture screenshots and recordings.

Overview

Many development tasks end in a browser: confirming that a layout fix rendered, reproducing a console error, filling in a form end to end, or reading a page of documentation. The /browser command tells the main agent to delegate your request to the specialized browser subagent through its invoke_subagent tool.

The browser subagent is purpose-built for this work:

• Real Chrome, real DevTools: the subagent controls Google Chrome through the Chrome DevTools MCP server, which Antigravity starts automatically when the subagent is invoked. No manual setup is required.
• Isolated context: like other subagents, it runs in its own conversation with a clean context window, so long page snapshots and console logs don’t crowd out your main conversation.
• Recorded sessions: every browser session is recorded and saved to the conversation’s artifacts as a WebM video. The recording is generated asynchronously, and the agent lets you know when it’s available.
• On demand only: the browser subagent is hidden from the agent’s normal subagent list. The main agent uses it only when you invoke /browser.

Note

The browser subagent isn’t available in the Antigravity IDE, and your organization’s administrator can disable browser access, in which case /browser doesn’t appear in the command menu. For browser features in the Antigravity IDE, refer to the IDE browser overview.

Run a browser task

Type /browser followed by the task. Describe a clear end condition so the subagent knows when to return, such as “report whether X renders” or “capture a screenshot of Y.”

Antigravity app

Antigravity app

Type the command in the composer:

/browser Open http://localhost:3000, resize to a 390px-wide mobile viewport, verify the navigation drawer opens and closes, and capture a screenshot of each state

The subagent’s progress appears in the subagent panel. Screenshots and the session recording are added to the conversation’s artifacts when the task completes.

Antigravity CLI

Antigravity CLI

Type the command in the interactive prompt:

/browser Open http://localhost:3000/dashboard, verify that the analytics charts render, and report any console errors

Press Alt+J or run /agents to switch into the subagent’s conversation and watch it work.

The first time the subagent connects, Chrome asks you to allow remote debugging. Accept the prompt so the subagent can attach to the browser.

What the browser subagent can do

The subagent has access to a focused set of Chrome DevTools tools:

Capability	Examples
Navigate and manage tabs	Open a URL, create or close pages, switch between tabs, wait for an element or text to appear.
Interact with the page	Click, hover, drag, press keys, type text, fill individual fields or whole forms, upload files, handle dialogs.
Inspect state	Take an accessibility snapshot of the page, capture a screenshot, list or fetch console messages and network requests.
Debug and profile	Evaluate JavaScript in the page, start and stop a performance trace, analyze performance insights, run a Lighthouse audit, take a heap snapshot.
Emulate conditions	Resize the viewport and emulate device and network conditions, such as throttled connections and CPU slowdown.

Running JavaScript in the page (evaluate_script) prompts for your approval by default. All other browser tools are allowed automatically for the subagent. You can adjust this in your tool permissions.

Example tasks

The following prompts show typical /browser workflows:

• Verify a UI fix:

  /browser Reload http://localhost:5173/settings and confirm the save button is no longer disabled after editing the display name

• Reproduce a console error:

  /browser Go to http://localhost:3000/checkout, add any item to the cart, and report the full text and stack of any console errors

• Check responsive and slow-network behavior:

  /browser Load http://localhost:3000 with a Slow 3G network profile and a 375px viewport, then screenshot the hero section once it finishes loading

• Research documentation:

  /browser Open the Astro docs for content collections and summarize how to define a schema with zod

Next steps

Explore related documentation:

• Subagents: Learn how built-in and custom subagents run in isolated contexts.
• Permissions: Control which browser tools run automatically and which ask first.
• Artifacts: Find screenshots and session recordings the subagent produces.
• Slash commands overview: Browse every available slash command.