Installation

Requirements

Node.js >= 20.19.0
Firefox 100+ installed

Claude Code CLI (Recommended)

claude mcp add firefox-devtools npx firefox-devtools-mcp@latest

With options:

# Headless + viewport via args
claude mcp add firefox-devtools npx firefox-devtools-mcp@latest -- --headless --viewport 1280x720

# Or via environment variables
claude mcp add firefox-devtools npx firefox-devtools-mcp@latest \
  --env START_URL=https://example.com \
  --env FIREFOX_HEADLESS=true

Claude Code Settings JSON

Add to your Claude Code config file:

macOS: ~/Library/Application Support/Claude/Code/mcp_settings.json
Linux: ~/.config/claude/code/mcp_settings.json
Windows: %APPDATA%\Claude\Code\mcp_settings.json

{
  "mcpServers": {
    "firefox-devtools": {
      "command": "npx",
      "args": ["-y", "firefox-devtools-mcp@latest", "--headless", "--viewport", "1280x720"],
      "env": {
        "START_URL": "about:home"
      }
    }
  }
}

Local Development

git clone https://github.com/freema/firefox-devtools-mcp.git
cd firefox-devtools-mcp
npm install
npm run build

Try with MCP Inspector

npx @modelcontextprotocol/inspector npx firefox-devtools-mcp@latest --start-url https://example.com --headless

Notes

This MCP server requires a local Firefox browser installation
Cannot run on cloud hosting services
Use npx firefox-devtools-mcp@latest to always use the latest version

Installation

Installation

Requirements

Claude Code CLI (Recommended)

Claude Code Settings JSON

Local Development

Try with MCP Inspector

Notes

On this page