Weather MCP Server

Instructions

Implementation Reference

• main.ts:18-46 (handler)

  Handler function that fetches geocoding data for the city, then retrieves current weather data from Open-Meteo API and returns it as JSON string.

  async ({ city }) => {
    const response = await fetch(`https://geocoding-api.open-meteo.com/v1/search?name=${city}&count=10&language=en&format=json`);
    const data = await response.json();
  
    if (data.results.length === 0) {
      return {
        content: [
          {
            type: "text",
            text: `No weather data found for ${city}`,
          }
        ]
      };
    }
  
    const {latitude, longitude} = data.results[0];
  
    const weatherResponse = await fetch(`https://api.open-meteo.com/v1/forecast?latitude=${latitude}&longitude=${longitude}¤t_weather=true&precipitation=true&hourly=temperature_2m¤t=precipitation,temperature_2m,rain,is_day`);
    const weatherData = await weatherResponse.json();
  
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(weatherData, null, 2)
        }
      ]
    };
  }

• main.ts:15-17 (schema)

  Zod schema defining the input parameter 'city' as a string.

  {
    city: z.string().describe("City name"),
  },

• main.ts:12-47 (registration)

  Registration of the 'get-weather' tool using server.tool(), including name, description, input schema, and handler function.

  server.tool(
    "get-weather",
    "Tool to fetch the weather for a given city",
    {
      city: z.string().describe("City name"),
    },
    async ({ city }) => {
      const response = await fetch(`https://geocoding-api.open-meteo.com/v1/search?name=${city}&count=10&language=en&format=json`);
      const data = await response.json();
  
      if (data.results.length === 0) {
        return {
          content: [
            {
              type: "text",
              text: `No weather data found for ${city}`,
            }
          ]
        };
      }
  
      const {latitude, longitude} = data.results[0];
  
      const weatherResponse = await fetch(`https://api.open-meteo.com/v1/forecast?latitude=${latitude}&longitude=${longitude}¤t_weather=true&precipitation=true&hourly=temperature_2m¤t=precipitation,temperature_2m,rain,is_day`);
      const weatherData = await weatherResponse.json();
  
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(weatherData, null, 2)
          }
        ]
      };
    }
  );