Weather MCP Server

Instructions

Implementation Reference

• index.js:355-401 (handler)

  MCP CallToolRequest handler block for 'get_weather' tool. Geocodes city, fetches weather forecast, formats and returns as JSON text content.

  if (request.params.name === "get_weather") {
    const cityName = request.params.arguments.city;
    const days = request.params.arguments.days || 7;
  
    try {
      // 1. 获取城市坐标
      const location = await geocodeCity(cityName);
  
      // 2. 获取天气数据
      const weather = await getWeatherForecast(
        location.latitude,
        location.longitude,
        location.timezone,
        days
      );
  
      // 3. 构建返回结果
      const result = {
        城市信息: {
          名称: location.name,
          国家: location.country,
          坐标: `${location.latitude}, ${location.longitude}`,
          时区: location.timezone
        },
        ...weather
      };
  
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(result, null, 2)
          }
        ]
      };
    } catch (error) {
      return {
        content: [
          {
            type: "text",
            text: `错误: ${error.message}`
          }
        ],
        isError: true
      };
    }
  }

• index.js:329-345 (schema)

  Input schema definition for the 'get_weather' tool in ListTools response.

  inputSchema: {
    type: "object",
    properties: {
      city: {
        type: "string",
        description: "城市名称，可以是中文或英文，例如：北京、Shanghai、New York等"
      },
      days: {
        type: "number",
        description: "预报天数，范围1-16天，默认7天",
        default: 7,
        minimum: 1,
        maximum: 16
      }
    },
    required: ["city"]
  }

• index.js:327-346 (registration)

  Tool registration in the ListToolsRequestSchema handler, defining name, description, and input schema for 'get_weather'.

    name: "get_weather",
    description: "获取指定城市的天气预报信息。支持1-16天的天气预报，包括温度、风力、舒适度、降雨降雪、紫外线指数、PM2.5等详细信息。",
    inputSchema: {
      type: "object",
      properties: {
        city: {
          type: "string",
          description: "城市名称，可以是中文或英文，例如：北京、Shanghai、New York等"
        },
        days: {
          type: "number",
          description: "预报天数，范围1-16天，默认7天",
          default: 7,
          minimum: 1,
          maximum: 16
        }
      },
      required: ["city"]
    }
  }

• index.js:43-114 (helper)

  Primary helper function that fetches current and forecast weather data from Open-Meteo API using coordinates, including air quality, and formats it.

  async function getWeatherForecast(latitude, longitude, timezone = 'auto', days = 7) {
    try {
      // 限制天数范围在 1-16 之间
      const forecastDays = Math.max(1, Math.min(16, days));
  
      // 构建天气 API URL
      const weatherParams = new URLSearchParams({
        latitude: latitude.toString(),
        longitude: longitude.toString(),
        timezone: timezone,
        // 每日天气数据
        daily: [
          'temperature_2m_max',           // 最高温度
          'temperature_2m_min',           // 最低温度
          'weathercode',                  // 天气代码
          'precipitation_sum',            // 降水量
          'rain_sum',                     // 降雨量
          'snowfall_sum',                 // 降雪量
          'windspeed_10m_max',           // 最大风速
          'windgusts_10m_max',           // 最大阵风
          'winddirection_10m_dominant',  // 主导风向
          'sunrise',                      // 日出时间
          'sunset',                       // 日落时间
          'uv_index_max'                  // 紫外线指数
        ].join(','),
        // 当前天气数据
        current: [
          'temperature_2m',
          'relative_humidity_2m',
          'apparent_temperature',         // 体感温度
          'weathercode',
          'windspeed_10m',
          'winddirection_10m',
          'uv_index'                      // 当前紫外线指数
        ].join(','),
        forecast_days: forecastDays.toString()
      });
  
      const weatherUrl = `https://api.open-meteo.com/v1/forecast?${weatherParams}`;
      const weatherResponse = await fetch(weatherUrl);
      const weatherData = await weatherResponse.json();
  
      if (weatherData.error) {
        throw new Error(`天气API错误: ${weatherData.reason || '未知错误'}`);
      }
  
      // 构建空气质量 API URL
      const airParams = new URLSearchParams({
        latitude: latitude.toString(),
        longitude: longitude.toString(),
        current: ['pm2_5', 'pm10'].join(',')
      });
  
      const airUrl = `https://air-quality-api.open-meteo.com/v1/air-quality?${airParams}`;
      let airData = null;
  
      try {
        const airResponse = await fetch(airUrl);
        airData = await airResponse.json();
        if (airData.error) {
          console.error('空气质量数据获取失败，将显示为无数据');
          airData = null;
        }
      } catch (error) {
        console.error('空气质量API调用失败:', error.message);
      }
  
      return formatWeatherData(weatherData, airData, forecastDays);
    } catch (error) {
      throw new Error(`获取天气数据失败: ${error.message}`);
    }
  }

• index.js:13-34 (helper)

  Helper function to convert city name to geographic coordinates (lat, lon, timezone) using Open-Meteo geocoding API.

  async function geocodeCity(cityName) {
    try {
      const url = `https://geocoding-api.open-meteo.com/v1/search?name=${encodeURIComponent(cityName)}&count=1&language=zh&format=json`;
      const response = await fetch(url);
      const data = await response.json();
  
      if (!data.results || data.results.length === 0) {
        throw new Error(`无法找到城市: ${cityName}`);
      }
  
      const result = data.results[0];
      return {
        name: result.name,
        country: result.country,
        latitude: result.latitude,
        longitude: result.longitude,
        timezone: result.timezone || 'auto'
      };
    } catch (error) {
      throw new Error(`地理编码失败: ${error.message}`);
    }
  }