Weather MCP Server

A Node.js Model Context Protocol (MCP) server that provides weather information tools using Streamable HTTP Transport.

Features

• get-alerts: Get weather alerts for a US state
• get-forecast: Get weather forecast for a location using latitude/longitude coordinates
• HTTP Transport: Uses streamable HTTP instead of stdio for better scalability
• Session Management: Supports multiple concurrent client sessions
• Health Check: Built-in health monitoring endpoint

Setup

1. Install dependencies:

npm install

2. Build the TypeScript code:

npm run build

3. Start the HTTP server:

npm start

The server will start on port 3000 by default.

Usage

This server implements the Model Context Protocol using HTTP transport. It provides:

• MCP Endpoint: http://localhost:3000/mcp
• Health Check: http://localhost:3000/health

get-alerts

Get weather alerts for a US state.

Parameters:

• state (string): Two-letter state code (e.g., "CA", "NY")

HTTP Example:

curl -X POST http://localhost:3000/mcp \
  -H "Content-Type: application/json" \
  -H "mcp-session-id: your-session-id" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "get-alerts",
      "arguments": {
        "state": "CA"
      }
    }
  }'

get-forecast

Get weather forecast for a location using coordinates.

Parameters:

• latitude (number): Latitude (-90 to 90)
• longitude (number): Longitude (-180 to 180)

HTTP Example:

curl -X POST http://localhost:3000/mcp \
  -H "Content-Type: application/json" \
  -H "mcp-session-id: your-session-id" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "get-forecast",
      "arguments": {
        "latitude": 40.7128,
        "longitude": -74.0060
      }
    }
  }'

MCP Client Configuration

Use this configuration in your MCP client:

{
  "mcpServers": {
    "weather": {
      "transport": {
        "type": "http",
        "url": "http://localhost:3000/mcp"
      }
    }
  }
}

Development

• Run in development mode:

npm run dev

• Test the server:

npm test

• Health check:

curl http://localhost:3000/health

Transport Features

• Session Management: Each client gets a unique session ID
• Concurrent Connections: Multiple clients can connect simultaneously
• Server-Sent Events: Real-time notifications via GET requests
• Session Termination: Clean session cleanup via DELETE requests
• DNS Rebinding Protection: Disabled for local development (enable in production)

Security Note

For production deployments, enable DNS rebinding protection:

// In src/index.ts
enableDnsRebindingProtection: true,
allowedHosts: ['your-domain.com'],
allowedOrigins: ['https://your-domain.com'],

Environment Variables

• PORT: Server port (default: 3000)

API Endpoints

• POST /mcp: Main MCP communication endpoint
• GET /mcp: Server-to-client notifications (SSE)
• DELETE /mcp: Session termination
• GET /health: Health check endpoint

Requirements

• Node.js 18 or higher
• TypeScript 5.5 or higher
• Internet connection for weather API access

Directory Structure

weather-server/
├── src/
│   └── index.ts          # Main HTTP server implementation
├── dist/                 # Compiled JavaScript output
├── package.json          # Node.js dependencies and scripts
├── tsconfig.json         # TypeScript configuration
├── test.js              # HTTP client test script
├── mcp-config.json      # MCP client configuration
└── README.md            # This file

Requirements

• Node.js 18 or higher
• TypeScript 5.5 or higher
• Internet connection for weather API access