browser-automation

name	browser-automation
description	This skill should be used when the user asks about browser automation, testing web pages, extracting content, filling forms, taking screenshots, or monitoring console/network activity. Activates for E2E testing, form automation, browsing tasks, or debugging web applications.

When the user asks about browser automation, use Firefox DevTools MCP to control a real Firefox browser.

Before Starting

Always call list_pages first. This checks whether Firefox is already running and which pages are open. Do not assume Firefox needs to be restarted or that you need to navigate from scratch — reuse the existing session whenever possible.

When to Use This Skill

Activate this skill when the user:

• Wants to automate browser interactions ("Fill out this form", "Click the login button")
• Needs E2E testing ("Test the checkout flow", "Verify the login works")
• Wants to browse or extract content ("Get all links on this page", "Extract prices")
• Needs screenshots ("Screenshot this page", "Capture the error state")
• Wants to debug ("Check for JS errors", "Show failed network requests")
• Needs to profile performance ("Profile this page load")

Core Workflow

Step 1: Navigate and Snapshot

navigate_page url="https://example.com"
take_snapshot

The snapshot returns a DOM representation with UIDs (e.g., e42) for each interactive element.

Step 2: Interact with Elements

Use UIDs from the snapshot:

fill_by_uid uid="e5" text="[e-mail]"
click_by_uid uid="e8"

Step 3: Re-snapshot After Changes

DOM changes invalidate UIDs. Always re-snapshot after:

• Page navigation
• Form submissions
• Dynamic content loads

take_snapshot  # Get fresh UIDs

Quick Reference

Task	Tools
Navigate	navigate_page, navigate_history
See DOM	take_snapshot
Click	click_by_uid
Hover	hover_by_uid
Type	fill_by_uid, fill_form_by_uid
Drag	drag_by_uid_to_uid
Dialogs	accept_dialog, dismiss_dialog
Screenshot	screenshot_page, screenshot_by_uid
Debug	list_console_messages, list_network_requests
Profile	profiler_start, profiler_stop

Guidelines

• Check existing session first: Call list_pages before navigating — reuse the running Firefox session rather than starting fresh
• Always snapshot first: UIDs only exist after take_snapshot
• Re-snapshot after DOM changes: UIDs become stale after interactions
• Screenshots: in Cowork (system prompt has an outputs folder host path), call screenshot_page saveTo="<host-outputs-path>/screenshot.png" then call present_files with that path. Otherwise call screenshot_page without saveTo and include the returned image directly in your reply — the user cannot see tool call outputs.
• Check for errors: Use list_console_messages level="error" to catch JS issues
• Firefox only: This MCP controls Firefox, not Chrome or Safari
• Reconfiguring Firefox: to use a specific binary, profile, or headless mode, call restart_firefox with the relevant options (firefoxPath, profilePath, headless)