Browser REPL WebSocket

A WebSocket-based browser automation tool with seamless MCP (Model Context Protocol) integration for Claude. Execute JavaScript in browsers remotely with zero configuration.

✨ Features

• 🚀 Zero Configuration: No environment variables or setup required
• 🔗 Automatic Session Management: Sessions saved automatically in ~/.replmirror-session
• 🔄 Session Switching: Paste code in multiple browsers to switch connections
• 🌐 WebSocket Secure: Uses WSS for secure browser connections
• 🤖 MCP Integration: Works seamlessly with Claude via browser-repl MCP tool
• 📱 Multi-Browser Support: Multiple browsers can connect to the same session

🚀 Quick Start

1. Generate Browser Connection Code

npx browser-repl-websocket@latest code

This will:

• Generate a unique session ID
• Save the session automatically to ~/.replmirror-session
• Display browser connection code

2. Connect Browser

Copy the generated JavaScript code and paste it into your browser's developer console.

3. Use with Claude

The MCP server automatically detects your session and connects to the browser. Simply ask Claude to use the browser-repl tool to execute JavaScript!

📋 Available Commands

Generate Browser Code

npx browser-repl-websocket@latest code
npx browser-repl-websocket@latest code --host https://replmirror.247420.xyz

• Creates a new browser session (defaults to localhost:8080)
• --host option sets remote host (e.g., https://replmirror.247420.xyz)
• --port option sets custom port (auto-detected from host protocol)
• Saves session to hidden file for persistence
• Outputs connection code for browser

Start MCP Server

npx browser-repl-websocket@latest mcp

• Automatically loads saved session
• Starts MCP server for Claude integration
• No arguments required - everything is automatic!

CLI Connection (Advanced)

npx browser-repl-websocket@latest connect --session <session-id>

🔧 Claude MCP Configuration

Add this to your .mcp.json file:

{
  "mcpServers": {
    "browser-repl": {
      "command": "npx",
      "args": ["-y", "browser-repl-websocket@latest", "mcp"]
    }
  }
}

Or add via CLI:

claude mcp add --scope project browser-repl -- npx -y browser-repl-websocket@latest mcp

🎯 Usage Examples

Basic JavaScript Execution

// Ask Claude to execute this:
document.title = "Hello from Claude!";
window.location.href

Get Page Information

return {
  title: document.title,
  url: window.location.href,
  userAgent: navigator.userAgent
};

DOM Manipulation

document.body.style.backgroundColor = 'lightblue';
document.querySelectorAll('a').forEach(link => console.log(link.href));

🔄 Session Management

• Automatic Persistence: Sessions saved to ~/.replmirror-session
• Remote Host Support: Use --host https://example.com to connect to remote WebSocket servers
• Session Switching: Latest browser connection gets priority
• Multi-MCP Support: Multiple MCP servers can connect to same session
• Isolation: Different sessions don't interfere with each other

🌐 Remote Host Configuration

Set Remote Host for New Session

npx browser-repl-websocket@latest code --host https://your-server.com

Update Existing Session to Remote Host

npx browser-repl-websocket@latest code --host https://replmirror.247420.xyz

Custom Port Configuration

npx browser-repl-websocket@latest code --host https://your-server.com --port 8080

The remote host configuration is automatically saved and will be used by both the browser connection code and the MCP server.

🏗️ Architecture

• src/core/websocket.js - WebSocket server with session management
• src/core/client.js - WebSocket client with role-based connections
• src/mcp/server.js - MCP browser automation server
• src/mcp/mcp-server.js - MCP protocol implementation
• src/utils/session.js - Session persistence and management

🛠️ Development

# Install dependencies
npm install

# Run locally
npm start

# Run tests
npm test

# Publish new version
npm version patch
npm publish

📄 License

MIT