Playwright-Lighthouse MCP server

This MCP server analyzes website performance using Playwright and Lighthouse through the Model Context Protocol (MCP), enabling LLMs to perform comprehensive web performance analysis. It offers performance scoring, improvement suggestions, and screenshot capabilities.

Installation

Prerequisites

• Node.js 18 or higher
• npm

Setting Up the Server

# Clone the repository
git clone https://github.com/kbyk004/playwright-lighthouse-mcp.git
cd playwright-lighthouse-mcp

# Install dependencies
npm install
npx playwright install

# Build
npm run build

Configuring with MCP Clients

The server works with any client supporting the Model Context Protocol. Here's how to set it up with Claude for Desktop:

Claude for Desktop Configuration

Add the following to your Claude for Desktop configuration file located at ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "playwright-lighthouse": {
      "command": "node",
      "args": [
        "/path-to/playwright-lighthouse-mcp/build/index.js"
      ]
    }
  }
}

Make sure to replace /path-to/ with the actual path to the repository on your system.

Starting the Server

To run the server in debug mode:

npm run inspector

Available Tools

Website Performance Analysis

The run-lighthouse tool performs Lighthouse analysis on websites:

{
  "url": "https://example.com",
  "categories": ["performance", "accessibility", "seo"],
  "maxItems": 3
}

Parameters:

• url: The website URL to analyze
• categories: Array of categories to include (options: "performance", "accessibility", "best-practices", "seo", "pwa")
• maxItems: Maximum improvement items to display per category (default: 3, max: 5)

Website Screenshots

The take-screenshot tool captures screenshots of websites:

{
  "url": "https://example.com",
  "fullPage": true
}

Parameters:

• url: The website URL to capture
• fullPage: Whether to capture the entire page (default: false)

Understanding Results

The analysis output includes:

• Overall scores for each requested category with color-coded indicators
• Prioritized improvement suggestions grouped by category
• Location of the saved report file for additional reference

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "playwright-lighthouse" '{"command":"node","args":["/path-to/playwright-lighthouse-mcp/build/index.js"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "playwright-lighthouse": {
            "command": "node",
            "args": [
                "/path-to/playwright-lighthouse-mcp/build/index.js"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "playwright-lighthouse": {
            "command": "node",
            "args": [
                "/path-to/playwright-lighthouse-mcp/build/index.js"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect