Basic MCP Weather Tool

Instructions

Implementation Reference

• main.ts:19-47 (handler)

  Handler function that performs geocoding for the city using Open-Meteo API, then fetches current and hourly weather data, returning it as JSON text.

    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 || data.results.length === 0) {
        return {
          content: [
            {
              type: 'text',
              text: `No se encontró información para la ciudad: ${city}.`,
            }
          ]
        };
      }
  
      const { latitude, longitude } = data.results[0];
  
      const weatherResponse = await fetch(`https://api.open-meteo.com/v1/forecast?latitude=${latitude}&longitude=${longitude}&hourly=temperature_2m¤t=temperature_2m,precipitation,is_day,rain&forecast_days=1`);
      const weatherData = await weatherResponse.json();
  
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify(weatherData, null, 2),
          }
        ]
      };
    }
  );

• main.ts:16-18 (schema)

  Input schema defining 'city' as a required string parameter.

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

• main.ts:13-15 (registration)

  Registration of the 'fetch-weather' tool with MCP server, including name, description, schema, and handler.

  server.tool(
    'fetch-weather',
    'Tool to fetch weather information',