agent-backend

Agent: Backend - Weather App

Purpose

Implement the weather service and API route with Open-Meteo integration (geocoding + weather).

Context Files to Load

• @context/intent/feature-weather-display.md
• @context/decisions/002-api-integration.md
• @context/knowledge/patterns/api-design.md

Scope

• Allowed directories: backend/src/
• Prohibited: Don't modify frontend

Execution Steps

1. Create Weather Service

   • Create backend/src/services/weather.service.ts
   • Implement Open-Meteo Geocoding API call (city name → coordinates)
   • Implement Open-Meteo Weather API call (coordinates → weather)
   • Map WMO weather codes to descriptions and icons
   • Handle API errors gracefully
   • Transform response to simplified format

2. Create Weather Route

   • Create backend/src/routes/weather.routes.ts
   • Implement GET /api/weather?city={city}
   • Add Swagger schema documentation
   • Register route in app.ts

3. Create Types

   • Create backend/src/types/weather.ts
   • Define request/response interfaces
   • Define geocoding and weather API response types

Expected Output

backend/src/
├── services/
│   └── weather.service.ts
├── routes/
│   └── weather.routes.ts
├── types/
│   └── weather.ts
├── plugins/
│   ├── swagger.ts
│   └── cors.ts
└── app.ts (updated with routes)

API Response Format

// GET /api/weather?city=London
{
  "success": true,
  "data": {
    "city": "London",
    "country": "United Kingdom",
    "temperature": 15.2,
    "description": "Overcast",
    "icon": "☁️",
    "windSpeed": 8.5,
    "windDirection": 180
  }
}

Implementation Notes

1. Geocoding First: Call https://geocoding-api.open-meteo.com/v1/search?name={city}&count=1
2. Weather Second: Use coordinates from geocoding to call https://api.open-meteo.com/v1/forecast?latitude={lat}&longitude={lon}&current_weather=true
3. Weather Code Mapping: Map WMO weather codes (0-99) to descriptions and icons (see 002-api-integration.md)
4. Error Handling: Handle cases where city is not found or API fails