MCP Weather Server Tutorial

This project demonstrates how to build a simple Model Context Protocol (MCP) server that provides weather information for any city using the Open-Meteo API.

Features

• MCP server using @modelcontextprotocol/sdk

• One tool: get-weather (returns weather for a given city)

• Uses geocoding and weather APIs from Open-Meteo

• Returns weather data in JSON format

How It Works

1. The MCP server exposes a tool called get-weather.

2. When a city name is provided, the server:

   • Uses Open-Meteo's geocoding API to get latitude and longitude for the city.

   • Fetches current weather data for those coordinates.

   • Returns the weather data as a JSON response.

3. If the city is not found, a helpful error message is returned.

Prerequisites

• Node.js (v18+ recommended)

• MCP Inspector (or any MCP client)

Setup

1. Clone this repository or copy the files to your workspace.

2. Install dependencies:

   npm install
   npm install node-fetch

3. Update your main.ts to import fetch from node-fetch if running in Node.js:

   import fetch from "node-fetch";

4. Start the MCP server using MCP Inspector:

   npx -y @modelcontextprotocol/inspector npx tsx main.ts

Usage

• Open MCP Inspector and connect to your server.

• Use the get-weather tool, enter a city name (e.g., "Paris", "Bangalore", "Chennai").

• The server will respond with the current weather data for that city.

Example Tool Response

{
  "latitude": 13,
  "longitude": 80.125,
  "current": {
    "temperature_2m": 30,
    "relative_humidity_2m": 66,
    "wind_speed_10m": 14.9,
    "cloud_cover": 94,
    "apparent_temperature": 33.2
  }
}

Troubleshooting

• If you see fetch is not defined, make sure you have installed and imported node-fetch.

• If the city is not found, check for typos or try a nearby major city.

License

MIT