Cypress MCP Server

A Model Context Protocol (MCP) server for Cypress that enables AI systems to create, execute, and analyze automated tests for web applications through the Model Context Protocol (MCP).

🎉 Enhanced Implementation

This project implements a robust HTTP transport with Server-Sent Events (SSE) support, following the same architecture as the Playwright MCP server. Our implementation leverages the official @modelcontextprotocol/sdk package to ensure full compliance with the MCP specification.

Features

• Standards-Compliant MCP Implementation: Implements the Model Context Protocol using the official SDK
• HTTP Transport with SSE Support: Reliable server-client communication using Server-Sent Events
• Streamable HTTP Support: Alternative transport method for compatible clients
• Natural Language Test Parsing: Convert plain English test scenarios into structured test plans
• Cypress Test Generation: Generate executable Cypress tests from structured test plans
• Test Execution: Run tests against real websites
• Test Reporting: Generate detailed reports of test execution results
• Containerized Deployment: Easy deployment using Docker

Available Tools

The Cypress MCP server provides the following categories of tools that AI systems can use to interact with web applications:

Core Testing Tools

• Test Generation: Convert natural language descriptions into executable Cypress tests
• Test Execution: Run tests against real websites and gather results
• Test Reporting: Generate detailed reports of test execution

Browser Automation Tools

Navigation Tools

• cypress_navigate - Navigate to a URL
• cypress_go_back - Go back in browser history
• cypress_go_forward - Go forward in browser history
• cypress_reload - Reload the current page

Element Interaction Tools

• cypress_click - Click on an element
• cypress_double_click - Double-click on an element
• cypress_type - Type text into an input element
• cypress_get_text - Get the text content of an element
• cypress_element_exists - Check if an element exists

Assertion Tools

• cypress_assert_text - Assert element contains specific text
• cypress_assert_visible - Assert element visibility
• cypress_assert_attribute - Assert element has attribute with value
• cypress_assert_url - Assert URL matches pattern
• cypress_assert_count - Assert number of elements matching selector

Screenshot Tools

• cypress_screenshot - Take a screenshot of the page
• cypress_element_screenshot - Screenshot a specific element

Wait Tools

• cypress_wait_for_element - Wait for element to meet condition
• cypress_wait_for_page_load - Wait for page to finish loading
• cypress_wait - Wait for fixed time
• cypress_wait_for_request - Wait for network request

Network Tools

• cypress_intercept_request - Intercept network requests
• cypress_mock_response - Mock network responses
• cypress_block_requests - Block network requests

Requirements

• Node.js 18 or newer
• Cypress 13.x or newer
• An MCP client (VS Code, Claude for VSCode, Anthropic Claude, GitHub Copilot, etc.)

Installation

Local Installation

1. Clone this repository
2. Install dependencies:

npm install

3. Build the project:

npm run build

4. Start the server:

node lib/cli-server.js http

To run in headless mode (recommended for production):

node lib/cli-server.js http --headless

Docker Installation

For easier deployment and isolation, you can use Docker:

1. Build the Docker image:

docker build -t cypress-mcp .

2. Run the container:

docker run -d --name cypress-mcp -p 3000:3000 -e NODE_ENV=production -e OPENAI_API_KEY=your-api-key-here -e HEADLESS=true cypress-mcp

Docker Compose Installation

Alternatively, you can use Docker Compose for easier management:

1. Create a .env file with your environment variables:

OPENAI_API_KEY=your-api-key-here
HEADLESS=true

2. Run with Docker Compose:

docker-compose up -d

VSCode Configuration

To use the Cypress MCP Server with VSCode or other AI assistants, add the following to your mcp_config.json file:

{
  "mcpServers": {
    "cypress": {
      "serverUrl": "http://localhost:3000/sse"
    }
  }
}

If your client supports streamable HTTP (check your client's documentation), you can also use:

{
  "mcpServers": {
    "cypress": {
      "serverUrl": "http://localhost:3000/mcp"
    }
  }
}

API Endpoints

The Cypress MCP server exposes the following endpoints:

• /health - Health check endpoint (responds with 200 OK if server is running)
• /sse - Server-Sent Events endpoint for MCP communication
• /mcp - Streamable HTTP endpoint for MCP communication (alternative transport)

Environment Variables

• OPENAI_API_KEY - API key for OpenAI services (used for enhanced test generation)
• HEADLESS - Run Cypress in headless mode (default: false)
• NODE_ENV - Node environment (development, production, etc.)
• PORT - Port to run the server on (default: 3000)

Development

Project Structure

├── src/
│   ├── cli.js              # CLI entrypoint for stdin/stdout transport
│   ├── cli-server.js       # CLI entrypoint for HTTP transport
│   ├── server.ts           # HTTP server implementation
│   ├── connection.ts       # MCP connection management
│   ├── context.ts          # Test context management
│   ├── tools/
│   │   ├── tool.ts         # Base tool definitions
│   │   ├── navigate.ts     # Navigation tools
│   │   ├── element.ts      # Element interaction tools
│   │   ├── assertions.ts   # Assertion tools
│   │   ├── screenshot.ts   # Screenshot tools
│   │   ├── wait.ts         # Wait tools
│   │   ├── network.ts      # Network tools
│   │   └── ...
└── ...

Extending the Server

To add new tools or functionality:

1. Create a new tool implementation in src/tools/
2. Register your tool in src/tools.ts
3. Build the project: npm run build
4. Test your changes

Testing

Run the tests with:

npm test

Troubleshooting

Common Issues

Connection Issues

If your MCP client cannot connect to the server:

1. Ensure the server is running (docker ps or check your terminal)
2. Verify the correct port is exposed and not blocked by a firewall
3. Check your mcp_config.json is correctly configured
4. Make sure you're using the correct endpoint (/sse or /mcp)

Browser Crashes

If Cypress browser crashes:

1. Increase the Docker container's memory limits
2. Check for browser compatibility issues
3. Make sure HEADLESS is set to true in production environments

License

MIT

Additional Resources

• Model Context Protocol (MCP) Documentation
• Cypress Documentation
• Playwright MCP Server

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

---

© 2025 Cypress MCP Server Contributors