Chrome Debug Mode Setup

This project provides the necessary scripts and configuration to run Chrome in debug mode for use with the Chrome DevTools MCP (Model Context Protocol).

Important: When using Chrome with the Chrome DevTools MCP, you MUST start Chrome with specific flags. The MCP cannot launch Chrome itself - it connects to an already-running instance.

Prerequisites

Before using this project, ensure you have the following installed:

Requirement	Version	Installation
Google Chrome	Latest	Download
Node.js	18+	Download
opencode	Latest	Download

Project Structure

project/
├── AGENTS.md                  # Agent guidelines
├── opencode.json              # MCP configuration
├── README.md                  # Project overview
├── INSTRUCTIONS.md            # Detailed documentation
├── util/
│   ├── start-chrome-debug.bat # Chrome startup script (Windows)
│   └── start-chrome-debug.sh # Chrome startup script (Mac/Linux)
└── docs/
    └── index.html             # This documentation

Quick Start

Step 1: Run the startup script to start Chrome in debug mode:

# Windows
util\start-chrome-debug.bat

# Mac/Linux (first time: chmod +x util/start-chrome-debug.sh)
./util/start-chrome-debug.sh

Step 2: Verify Chrome is running correctly by visiting:

http://localhost:9222/json

You should see a JSON response listing available pages/tabs.

Step 3: Use the Chrome DevTools MCP to control the browser. The MCP is already configured in opencode.json to connect to localhost:9222.

Startup Flags Explained

Required

--remote-debugging-port=9222

Enables the Chrome DevTools Protocol on port 9222, allowing the MCP to connect and control the browser.

MCP Configuration

The project includes an opencode.json file that configures the Chrome DevTools MCP:

{
  "mcp": {
    "chrome-devtools": {
      "type": "local",
      "command": ["npx", "-y", "chrome-devtools-mcp@latest", "--browser-url=http://localhost:9222"],
      "enabled": true
    }
  }
}

Troubleshooting

If the MCP cannot connect:

Ensure Chrome was started with --remote-debugging-port=9222
Check that no other Chrome instance is using the same port
Verify the debug port is listening: netstat -ano | findstr :9222
Make sure you're not running Chrome normally alongside the debug instance

Manual Chrome Startup

If you prefer to start Chrome manually, run:

"C:\Program Files\Google\Chrome\Application\chrome.exe" --remote-debugging-port=9222 --no-first-run --no-default-browser-check --user-data-dir=%TEMP%\chrome-debug