What can you do with this server?

The Firefox MCP Server provides comprehensive browser automation for AI assistants with multi-session management, advanced debugging, and web interaction capabilities. Browser & Session Management: Launch Firefox with headless mode and debug logging options, create multiple isolated tabs/sessions with independent state (cookies, storage, debugging contexts), list active tabs, close specific tabs or entire browser, and set active tabs. Navigation & Interaction: Navigate to URLs, control browser history (back/forward/reload), click elements by selector or coordinates, type text into fields, send keyboard events with modifiers and repeats, perform drag-and-drop with smooth animations, and wait for elements with configurable timeouts. Content & Execution: Execute custom JavaScript in browser contexts, extract HTML content from pages or elements, retrieve visible text, and take screenshots with full-page capture and custom paths. Comprehensive Debugging: * Console Monitoring: Capture and filter logs (log, error, warn, info, debug) by type and time * Error Tracking: Capture JavaScript exceptions with stack traces * Network Analysis: Monitor HTTP requests/responses with timing data, filter by type (XHR, WebSocket, fetch) * WebSocket Traffic: Capture real-time bidirectional messages * Performance Metrics: DOM timing, paint events, and memory usage * Unified Debug Feed: Combined view of all debugging events * Control Tools: Start/stop monitoring with selective event types, clear debug buffers, inject debugging helper functions Ideal for: Multi-user application testing, multiplayer game development, Phoenix LiveView debugging, automated UI testing with visual verification, real-time WebSocket analysis, and performance optimization.

Which integrations are available for this server?

Provides Firefox browser automation capabilities through Playwright, allowing control of Firefox for web testing. Features include browser navigation, element interaction, multi-tab session support, and advanced debugging features like console log monitoring, JavaScript error tracking, and WebSocket traffic monitoring. Enables execution of JavaScript code in browser contexts, monitoring of JavaScript errors and console logs, and tracking of unhandled errors and promise rejections with full stack traces. Server runs on Node.js and supports interaction with Node.js applications through browser automation, providing capabilities for testing and debugging Node.js web applications.

How do I use Firefox MCP Server?

1. Click on "Install Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@Firefox MCP Server debug the WebSocket messages on my multiplayer game page" That's it! The server will respond to your query, and you can continue using it as needed. Here is a step-by-step guide with screenshots.

Firefox MCP Server

Advanced Firefox browser automation with comprehensive debugging capabilities

A powerful Model Context Protocol (MCP) server that provides sophisticated Firefox browser automation through 28 specialized tools. Designed for AI assistants and automation workflows requiring multi-session management, real-time debugging, and comprehensive web interaction capabilities.

🌟 Key Features

Multi-Session Architecture

Isolated Browser Sessions: Each session runs in a completely separate context with independent cookies, storage, and debugging
Perfect for Multiplayer Testing: Test multiplayer games and multi-user applications seamlessly
Concurrent Operations: Manage multiple browser sessions simultaneously from a single interface

Comprehensive Debugging Suite

Real-time Console Monitoring: Capture all console output (log, error, warn, info, debug)
JavaScript Error Tracking: Monitor unhandled errors with full stack traces
Network Activity Monitoring: Track HTTP requests, responses, and timing data
WebSocket Traffic Capture: Perfect for Phoenix LiveView and real-time application debugging
Performance Metrics: Monitor DOM timing, paint events, and memory usage

Advanced Interaction Capabilities

Precise Element Interaction: Click, type, and interact with any web element
Keyboard Event Simulation: Send complex key combinations and shortcuts
Drag & Drop Operations: Smooth drag operations with customizable timing and steps
JavaScript Execution: Run custom JavaScript in browser contexts

Related MCP server: Playwright MCP

🚀 Quick Start

Installation

npm install firefox-mcp-server npx playwright install firefox

Basic Usage

Add to your MCP client configuration:

{ "mcpServers": { "firefox": { "command": "npx", "args": ["firefox-mcp-server"], "env": {} } } }

Example: Multi-User Testing

// Launch browser and create isolated sessions await browser_launch({headless: false}) await session_create({sessionId: "user1", url: "https://app.example.com"}) await session_create({sessionId: "user2", url: "https://app.example.com"}) // User 1 creates a game await element_click({sessionId: "user1", selector: "button.create-game"}) // User 2 joins the game await element_click({sessionId: "user2", selector: "button.join-game"}) await input_type({sessionId: "user2", selector: "input.game-code", text: "ABC123"}) // Monitor both sessions for real-time updates await debug_websocket_messages({sessionId: "user1", limit: 10}) await debug_websocket_messages({sessionId: "user2", limit: 10})

🛠️ Complete Tool Reference

Browser Management

browser_launch - Launch Firefox with debugging capabilities
browser_close - Close browser and clean up all resources

Session Management

session_create - Create isolated browser session with independent state
session_list - List all active sessions with URLs and status
session_close - Close specific session and free resources
session_set_active - Set default session for subsequent operations

page_navigate - Navigate to any URL
page_reload - Refresh current page
history_back / history_forward - Browser history navigation
url_get_current - Get current page URL

Element Interaction

element_click - Click elements by selector or coordinates
element_drag - Drag and drop with smooth animations
input_type - Type text into input fields and text areas
keyboard_press - Send keyboard events with modifier support
element_wait - Wait for elements to appear or become visible

Content Extraction

html_extract - Extract HTML content from page or elements
text_extract - Get visible text content
page_screenshot - Capture screenshots with flexible options

Advanced Capabilities

javascript_execute - Run custom JavaScript in browser context

Comprehensive Debugging Tools

debug_console_logs - Monitor browser console output
debug_javascript_errors - Track JavaScript errors and exceptions
debug_network_activity - Monitor HTTP requests and responses
debug_websocket_messages - Capture WebSocket traffic (LiveView-friendly)
debug_performance_metrics - Get timing and memory usage data
debug_activity_all - Combined feed of all debugging information
debug_monitoring_start - Start comprehensive monitoring
debug_buffers_clear - Clear accumulated debug data
debug_helpers_inject - Inject custom debugging utilities

🎯 Use Cases

Web Application Testing

Automated UI testing with visual verification
Form submission and validation testing
Cross-browser compatibility verification
Performance monitoring and optimization

Multiplayer Game Development

Multi-player session simulation
Real-time state synchronization testing
WebSocket message flow debugging
Client-side prediction validation

Phoenix LiveView Development

LiveView event flow monitoring
Real-time update verification
WebSocket connection debugging
Multi-user interaction testing

E-commerce and SaaS Testing

Multi-user checkout flows
Session isolation for different user roles
Real-time inventory updates
Payment flow testing

📊 Debugging Capabilities

Console Monitoring

// Get recent console activity await debug_console_logs({ sessionId: "user1", types: ["error", "warn"], limit: 20, since: Date.now() - 60000 // Last minute })

Network Analysis

// Monitor API calls and responses await debug_network_activity({ sessionId: "user1", filter: "xhr", limit: 10 })

WebSocket Debugging

// Perfect for Phoenix LiveView await debug_websocket_messages({ sessionId: "user1", limit: 5 })

Performance Monitoring

// Get comprehensive performance data await debug_performance_metrics({ sessionId: "user1" })

⚙️ Troubleshooting

Playwright Browser Not Found Error

If you encounter an error like:

browserType.launch: Executable doesn't exist at /home/luke/.cache/ms-playwright/firefox-1482/firefox/firefox

Solution: The Playwright browsers need to be installed. Run:

# From the firefox-mcp-server directory ./node_modules/.bin/playwright install firefox

This downloads the Firefox browser binary that Playwright uses for automation. This issue was resolved on 2025-08-03 when the MCP server failed to launch due to missing browser binaries.

🔧 Claude Code Configuration

Local Configuration

Claude Code uses a project-specific configuration located at:

/home/luke/workbench/drabardi/.claude/settings.local.json

This configuration includes:

Enabled MCP Servers: The firefox-control server is enabled in enabledMcpjsonServers
Permissions: Various tool permissions are whitelisted including all Firefox MCP tools

MCP Server Configuration

The Firefox MCP server is configured in Claude Code using:

# Check configured MCP servers claude mcp list # Output shows: firefox-control: node /home/luke/workbench/firefox-mcp-server/index.js tidewave: http://localhost:4000/tidewave/mcp (SSE)

The server runs from /home/luke/workbench/firefox-mcp-server/ using the main index.js file (which internally uses the index-multi-debug.js implementation).

🔧 Configuration Options

Session Creation

await session_create({ sessionId: "unique-id", url: "https://example.com", contextId: "optional-context", enableMonitoring: true // Enable real-time debugging })

Screenshot Options

await page_screenshot({ sessionId: "user1", path: "screenshot.png", fullPage: true // Capture entire page })

Drag Operations

await element_drag({ sessionId: "user1", selector: ".slider", offsetX: 100, duration: 1000, // Smooth 1-second animation steps: 20 // 20 intermediate positions })

📁 Project Structure

firefox-mcp-server/ ├── index.js # Main MCP server implementation ├── package.json # Project configuration ├── README.md # This file ├── CLAUDE.md # Claude Code integration guide ├── examples/ # Usage examples │ ├── demo-tibia-simple.js │ ├── demo-tibia.js │ └── demo-multiplayer.js ├── tests/ # Test files │ └── test.js └── docs/ # Additional documentation ├── ENHANCEMENT_USAGE.md └── README-multi.md

🤝 Contributing

We welcome contributions! This project is designed to be:

LLM-Friendly: Tool names and descriptions optimized for AI assistant discovery
Extensible: Easy to add new browser automation capabilities
Well-Documented: Comprehensive examples and documentation

📋 Requirements

Node.js: 18.0.0 or higher
Firefox: Automatically installed via Playwright
MCP Client: Claude Code, Cline, or other MCP-compatible tools

🔒 Security

This server provides comprehensive browser automation capabilities. Use with trusted MCP clients only. The server can:

Execute arbitrary JavaScript in browser contexts
Monitor all network traffic and WebSocket messages
Access page content and user interactions
Take screenshots and access media devices

📄 License

MIT License - see LICENSE file for details.

Perfect for AI assistants working with web applications, multiplayer games, and real-time debugging scenarios.

Install Server

security – no known vulnerabilities

license - permissive license

quality - confirmed to work

How are these scores calculated?

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