Weather MCP Server

Instructions

Implementation Reference

• src/index.js:192-238 (handler)

  The main handler function that fetches current weather data for a specified city (default Sydney) using Open-Meteo APIs, formats and returns the response.

    async getCurrentWeather(city, country) {
      let location;
      
      if (city.toLowerCase() === 'sydney' && !country) {
        location = DEFAULT_LOCATION;
      } else {
        location = await this.getCoordinates(city, country);
      }
  
      const url = `${WEATHER_API}?latitude=${location.latitude}&longitude=${location.longitude}¤t=temperature_2m,relative_humidity_2m,apparent_temperature,is_day,precipitation,rain,showers,snowfall,weather_code,cloud_cover,pressure_msl,surface_pressure,wind_speed_10m,wind_direction_10m,wind_gusts_10m&timezone=auto`;
      
      const response = await fetch(url);
      const data = await response.json();
  
      if (!response.ok) {
        throw new Error('Erreur lors de la récupération de la météo');
      }
  
      const current = data.current;
      const weatherDesc = this.getWeatherDescription(current.weather_code);
      const windDir = this.getWindDirection(current.wind_direction_10m);
      
      return {
        content: [
          {
            type: 'text',
            text: `🌤️ Météo actuelle à ${location.name || location.admin1 || 'Localisation'}${location.country ? `, ${location.country}` : ''}
  
  📍 **Localisation:** ${location.latitude}°, ${location.longitude}°
  🌡️ **Température:** ${Math.round(current.temperature_2m)}°C
  🤔 **Ressenti:** ${Math.round(current.apparent_temperature)}°C
  ☁️ **Conditions:** ${weatherDesc} ${current.is_day ? '☀️' : '🌙'}
  💧 **Humidité:** ${current.relative_humidity_2m}%
  🌬️ **Vent:** ${Math.round(current.wind_speed_10m)} km/h ${windDir}
  💨 **Rafales:** ${Math.round(current.wind_gusts_10m)} km/h
  🔽 **Pression:** ${Math.round(current.pressure_msl)} hPa
  ☁️ **Couverture nuageuse:** ${current.cloud_cover}%
  
  ${current.precipitation > 0 ? `🌧️ **Précipitations:** ${current.precipitation} mm` : ''}
  ${current.rain > 0 ? `🌧️ **Pluie:** ${current.rain} mm` : ''}
  ${current.snowfall > 0 ? `❄️ **Neige:** ${current.snowfall} cm` : ''}
  
  ⏰ **Dernière mise à jour:** ${new Date(current.time).toLocaleString('fr-FR')}`,
          },
        ],
      };
    }

• src/index.js:51-69 (registration)

  Registration of the 'get_current_weather' tool in the ListTools response, including name, description, and input schema.

  {
    name: 'get_current_weather',
    description: 'Récupère la météo actuelle pour une ville (Sydney par défaut)',
    inputSchema: {
      type: 'object',
      properties: {
        city: {
          type: 'string',
          description: 'Nom de la ville (optionnel, Sydney par défaut)',
          default: 'Sydney'
        },
        country: {
          type: 'string',
          description: 'Code pays optionnel (ex: AU, FR, US)',
        }
      },
      required: [],
    },
  },

• src/index.js:146-147 (registration)

  Dispatcher case in CallToolRequestSchema handler that routes calls to the getCurrentWeather method.

  case 'get_current_weather':
    return await this.getCurrentWeather(args.city || 'Sydney', args.country);

• src/index.js:178-190 (helper)

  Helper function to resolve city name to coordinates using geocoding API, used by getCurrentWeather.

  async getCoordinates(city, country) {
    const query = country ? `${city}, ${country}` : city;
    const url = `${GEOCODING_API}?name=${encodeURIComponent(query)}&count=1&language=fr&format=json`;
    
    const response = await fetch(url);
    const data = await response.json();
  
    if (!response.ok || !data.results || data.results.length === 0) {
      throw new Error(`Ville "${query}" non trouvée`);
    }
  
    return data.results[0];
  }

• src/index.js:395-428 (helper)

  Helper to translate weather codes to human-readable descriptions.

  getWeatherDescription(code) {
    const descriptions = {
      0: 'Ciel dégagé',
      1: 'Principalement dégagé',
      2: 'Partiellement nuageux',
      3: 'Couvert',
      45: 'Brouillard',
      48: 'Brouillard givrant',
      51: 'Bruine légère',
      53: 'Bruine modérée',
      55: 'Bruine dense',
      56: 'Bruine verglaçante légère',
      57: 'Bruine verglaçante dense',
      61: 'Pluie légère',
      63: 'Pluie modérée',
      65: 'Pluie forte',
      66: 'Pluie verglaçante légère',
      67: 'Pluie verglaçante forte',
      71: 'Neige légère',
      73: 'Neige modérée',
      75: 'Neige forte',
      77: 'Grains de neige',
      80: 'Averses légères',
      81: 'Averses modérées',
      82: 'Averses violentes',
      85: 'Averses de neige légères',
      86: 'Averses de neige fortes',
      95: 'Orage',
      96: 'Orage avec grêle légère',
      99: 'Orage avec grêle forte'
    };
    
    return descriptions[code] || 'Conditions inconnues';
  }