Chrome DevTools Skill

Control Chrome browser programmatically using the Chrome DevTools Protocol. This skill provides 26 tools for browser automation, web scraping, testing, and performance analysis.

Prerequisites

• Node.js 18+ installed
• mcp2rest running on http://localhost:28888
• chrome-devtools server loaded in mcp2rest
• Package: chrome-devtools-mcp@latest
• Dependencies installed (already done during generation)

Quick Start

Launch a browser, navigate to a page, and interact with elements:

# 1. Open a new page
node scripts/new_page.js --url https://example.com

# 2. Take a text snapshot to identify elements
node scripts/take_snapshot.js

# 3. Click a button (use UID from snapshot output)
node scripts/click.js --uid button_submit_abc123

Expected Output:

• Page opens in Chrome browser
• Snapshot shows page structure with element UIDs
• Button is clicked and any action triggers

Tool Groups

This skill provides 26 tools organized into 4 groups:

1. Page Management

Browser window and tab operations: creating pages, navigation, switching contexts.

Tools: newpage, listpages, closepage, navigatepage, selectpage, resizepage

See: @workflows/page-management.md for detailed workflows

2. Element Interaction

User input simulation: clicking, typing, form filling, drag & drop.

Tools: click, fill, fillform, hover, drag, uploadfile, press_key

See: @workflows/element-interaction.md for detailed workflows

3. Inspection & Debugging

Monitoring and debugging: snapshots, screenshots, console logs, network requests.

Tools: takesnapshot, takescreenshot, listconsolemessages, getconsolemessage, listnetworkrequests, getnetworkrequest

See: @workflows/inspection-debugging.md for detailed workflows

4. Performance Analysis

Scripting and performance tools: JavaScript execution, performance tracing, device emulation.

Tools: evaluatescript, waitfor, handledialog, emulate, performancestarttrace, performancestoptrace, performanceanalyze_insight

See: @workflows/performance-analysis.md for detailed workflows

Common Workflows

Workflow: Automated Form Submission

Complete end-to-end form filling and submission:

• Open page: node scripts/new_page.js --url https://example.com/login
• Get structure: node scripts/take_snapshot.js (identify UIDs)
• Fill email: node scripts/fill.js --uid emailinputxyz --value [email protected]
• Fill password: node scripts/fill.js --uid passinputabc --value mypassword
• Submit form: node scripts/click.js --uid submitbtndef
• Verify: node scripts/wait_for.js --text "Welcome" --timeout 5000
• Capture result: node scripts/take_screenshot.js --format png --filePath result.png

Input Example:

Email field UID: input_email_1a2b3c
Password field UID: input_password_4d5e6f
Submit button UID: button_submit_7g8h9i

Expected Output: Form submitted successfully, redirected to dashboard, screenshot saved.

Workflow: Web Scraping with Network Monitoring

Capture page data and network activity:

• Start monitoring: node scripts/new_page.js --url https://example.com/data
• Wait for load: node scripts/wait_for.js --text "Data loaded" --timeout 10000
• Get page snapshot: node scripts/take_snapshot.js --verbose true --filePath snapshot.txt
• List network calls: node scripts/listnetworkrequests.js --resourceTypes fetch,xhr
• Get specific request: node scripts/getnetworkrequest.js --reqid request_123
• Extract via script: node scripts/evaluate_script.js --function "() => document.querySelector('.data').textContent"

Expected Output: Page data extracted, network requests logged, specific API responses captured.

Workflow: Performance Testing

Analyze page performance and Core Web Vitals:

• Open page: node scripts/new_page.js --url https://example.com
• Start tracing: node scripts/performancestarttrace.js --reload true --autoStop false
• Wait for page: node scripts/wait_for.js --text "Content loaded" --timeout 15000
• Stop tracing: node scripts/performancestoptrace.js
• Review insights: Check trace output for performance metrics and CWV scores
• Analyze specific insight: node scripts/performanceanalyzeinsight.js --insightSetId set_123 --insightName LargestContentfulPaint

Expected Output: Performance trace with metrics, CWV scores (LCP, FID, CLS), actionable insights.

Workflow: Multi-Page Session Management

Work with multiple browser tabs:

• List current pages: node scripts/list_pages.js
• Open new tab: node scripts/new_page.js --url https://example.com/page1
• Open another tab: node scripts/new_page.js --url https://example.com/page2
• List all pages: node scripts/list_pages.js (note page indices)
• Switch to page 0: node scripts/select_page.js --pageIdx 0
• Interact with page 0: node scripts/take_snapshot.js
• Switch to page 1: node scripts/select_page.js --pageIdx 1
• Close page 1: node scripts/close_page.js --pageIdx 1

Expected Output: Multiple tabs managed, context switching works, specific pages closed.

State Persistence

This server maintains state between script calls:

• Browser instance stays open across multiple commands
• Page context persists until explicitly changed with select_page.js
• Console messages and network requests accumulate since last navigation
• State resets when mcp2rest server restarts

Reference

• Complete tool listing: @reference/all-tools.md
• Troubleshooting guide: @reference/troubleshooting.md
• Advanced examples: @reference/advanced-examples.md

Quick Tips

1. Always take snapshots first: Use take_snapshot.js to get element UIDs before interaction
2. Use wait_for for dynamic content: Don't assume instant loading
3. Handle dialogs proactively: Use handle_dialog.js if alerts/confirms appear
4. Check console for errors: Use listconsolemessages.js to debug issues
5. Monitor network for API calls: Use listnetworkrequests.js to track backend communication