Weather MCP Server

Instructions

Implementation Reference

• index.js:85-113 (handler)

  The main handler function that fetches current weather data for a given city using the OpenWeatherMap API via axios, formats the response as MCP content, and handles errors.

      async getWeather(city) {
          if (!API_KEY) {
              throw new Error("OpenWeatherMap API key not found. Set OPENWEATHER_API_KEY environment variable.");
          }
  
          try {
              const response = await axios.get(
                  `https://api.openweathermap.org/data/2.5/weather?q=${city}&appid=${API_KEY}&units=metric`
              );
  
              const weather = response.data;
  
              return {
                  content: [
                      {
                          type: "text",
                          text: `Weather in ${weather.name}, ${weather.sys.country}:
  Temperature: ${weather.main.temp}°C (feels like ${weather.main.feels_like}°C)
  Condition: ${weather.weather[0].description}
  Humidity: ${weather.main.humidity}%
  Wind: ${weather.wind.speed} m/s
  Pressure: ${weather.main.pressure} hPa`,
                      },
                  ],
              };
          } catch (error) {
              throw new Error(`Failed to get weather for ${city}: ${error.message}`);
          }
      }

• index.js:37-46 (schema)

  Input schema definition for the get_weather tool, specifying a required 'city' string parameter.

  inputSchema: {
      type: "object",
      properties: {
          city: {
              type: "string",
              description: "Name of the city to get weather for",
          },
      },
      required: ["city"],
  },

• index.js:34-47 (registration)

  Registration of the get_weather tool in the ListToolsRequestSchema handler, including name, description, and input schema.

  {
      name: "get_weather",
      description: "Get current weather for a city",
      inputSchema: {
          type: "object",
          properties: {
              city: {
                  type: "string",
                  description: "Name of the city to get weather for",
              },
          },
          required: ["city"],
      },
  },

• index.js:73-75 (registration)

  Dispatch/registration logic in the CallToolRequestSchema handler that checks the tool name and invokes the getWeather handler.

  if (name === "get_weather") {
      return await this.getWeather(args.city);
  }