Playwright React Debug MCP

Debug React applications with AI assistance using Claude and Playwright.

A Model Context Protocol (MCP) server that gives Claude the ability to interact with live web applications through a browser. Navigate pages, inspect the DOM, monitor network requests, debug React components, and analyze errors—all through natural conversation.

Why Use This?

| Traditional Debugging | With Playwright React Debug MCP | |-----------------------|---------------------------| | Manually reproduce issues | "Navigate to /dashboard and check for errors" | | Screenshot and paste into chat | Claude sees the live page and interacts directly | | Copy-paste console errors | Console logs captured automatically | | Open React DevTools manually | Claude queries component tree with state/props | | Check Network tab for failures | All HTTP traffic monitored and analyzed |

Features

• 40 debugging tools across 10 categories
• Browser Control - Navigate, click, fill forms, automate user flows
• DOM Inspection - Element details, computed styles, text extraction
• Network Monitoring - Request/response bodies, headers, timing
• Console Capture - Errors, warnings, logs with filtering
• React DevTools - Component tree, props, state, hooks inspection
• State Management - Redux, Zustand, React Query, Context inspection
• Performance - Render tracking, slow components, Web Vitals
• Error Detection - Hydration errors, error boundaries, memory leaks
• Accessibility - WCAG-style audits, ARIA tree inspection
• Error Analysis - AI-powered analysis with suggested fixes

Quick Start

Install

npm install -g playwright-react-debug-mcp
npx playwright install chromium

Configure Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "playwright-debug": {
      "command": "npx",
      "args": ["playwright-react-debug-mcp"]
    }
  }
}

Configure Claude Code

Add to your project's .mcp.json:

{
  "mcpServers": {
    "playwright-debug": {
      "command": "npx",
      "args": ["playwright-react-debug-mcp"],
      "transport": "stdio"
    }
  }
}

Try It

You: Navigate to https://example.com and take a screenshot

Claude: I'll navigate to the page and capture a screenshot.
[Browser opens, navigates, returns screenshot]

Done! The page shows...

Example Session

You: Navigate to my app at localhost:3000/login and try logging in
     with [email protected]

Claude: I'll navigate to the login page and fill in the credentials.

[Navigates, fills email/password, clicks submit]

The login failed. Let me check what happened:

- Console: "TypeError: Cannot read property 'token' of undefined"
- Network: POST /api/auth returned 200 but body is empty
- React: AuthProvider shows { isAuthenticated: false, error: null }

The API returns 200 without a token. The frontend expects response.data.token
but data is undefined. The error state isn't being set because the HTTP
status was 200.

Suggestions:
1. Backend should return { data: { token: "..." } } or proper error status
2. Frontend should validate response structure, not just HTTP status

Available Tools

Navigation & Interaction (11 tools)

| Tool | Description | |------|-------------| | navigate | Navigate to URL with wait conditions | | click | Click elements (left/right/double) | | fill | Fill form fields | | select | Select dropdown options | | type | Type text character-by-character | | hover | Hover over elements | | scroll | Scroll page or element into view | | wait_for | Wait for element/navigation | | go_back | Browser back | | go_forward | Browser forward | | reload | Reload page |

Inspection (3 tools)

| Tool | Description | |------|-------------| | get_dom | Summarized DOM tree | | get_element | Element details with styles | | get_text_content | Extract visible text |

Network (3 tools)

| Tool | Description | |------|-------------| | get_network | View requests with filtering | | get_request_detail | Full request/response details | | clear_network | Clear captured requests |

Console (2 tools)

| Tool | Description | |------|-------------| | get_console | View logs with filtering | | clear_console | Clear captured logs |

React (4 tools)

| Tool | Description | |------|-------------| | get_react_tree | Component tree with hooks | | find_component | Search components by name | | get_component_state | Detailed state/props | | collect_component_instances | All instances of a component |

State Management (4 tools)

| Tool | Description | |------|-------------| | get_redux_state | Redux store state + actions | | get_zustand_stores | Zustand store inspection | | get_react_query_cache | React Query cache | | get_context_values | React Context values |

Performance (3 tools)

| Tool | Description | |------|-------------| | get_render_count | Component render tracking | | get_slow_components | Slow component detection | | get_web_vitals | Core Web Vitals (LCP, CLS, etc.) |

Error Detection (3 tools)

| Tool | Description | |------|-------------| | find_hydration_errors | SSR hydration mismatches | | get_error_boundaries | React error boundaries | | detect_memory_leaks | Memory leak indicators |

Accessibility (2 tools)

| Tool | Description | |------|-------------| | run_accessibility_audit | WCAG-style audit | | get_aria_tree | Accessibility tree |

Advanced (5 tools)

| Tool | Description | |------|-------------| | screenshot | Capture page or element | | evaluate_js | Execute JavaScript | | explain_error | AI error analysis | | get_debug_summary | Page state overview |

Use Cases

Interactive Debugging

What errors are on this page?
Why did the form submission fail?

Automated Testing

Fill the registration form and verify it submits successfully
Click through the checkout flow and check for errors

React Development

Find the UserProfile component and show its state
What props are being passed to the Modal?
Collect all Button instances and compare their usage

API Integration

What requests were made when I clicked submit?
Show me the response from the failed API call

Configuration

Environment Variables

| Variable | Default | Description | |----------|---------|-------------| | MAX_CONSOLE_ENTRIES | 100 | Console log buffer size | | MAX_NETWORK_ENTRIES | 100 | Network request buffer size | | PLAYWRIGHT_HEADLESS | false | Run browser headless |

{
  "mcpServers": {
    "playwright-debug": {
      "command": "npx",
      "args": ["playwright-react-debug-mcp"],
      "env": {
        "PLAYWRIGHT_HEADLESS": "true"
      }
    }
  }
}

Development

# Clone
git clone https://github.com/Lars-Albinsson/playwright-react-debug-mcp
cd playwright-react-debug-mcp

# Install
npm install
npx playwright install chromium

# Build
npm run build

# Run
npm start

# Watch mode
npm run dev

Documentation

• Getting Started
• Tools Reference
• Examples

Requirements

• Node.js 18+
• Playwright (Chromium)
• Claude Desktop or Claude Code

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

License

MIT License - see LICENSE for details.

Related

• Model Context Protocol
• Playwright
• Claude