Simple Weather Tool

Minimal MCP weather server for LM Studio. Fetches live weather from Open-Meteo. No API key required. Returns structured JSON with location disambiguation.

Use it as a drop-in tool in LM Studio chat, or run the optional Python CLI demo.

Features

• MCP stdio server compatible with LM Studio 0.3.17+
• Structured JSON weather output (temperature, conditions, humidity, wind, etc.)
• Location disambiguation via country_code and optional region
• Optional travel-advisor system prompt
• Optional CLI agent demo for developers

Requirements

• Python 3.12+
• LM Studio 0.3.17+ (for chat integration)
• Internet access (Open-Meteo API)
• A local model with tool/function calling support

Install

git clone https://github.com/yourname/simple-mcp-weather.git
cd simple-mcp-weather
python -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate
pip install -r requirements.txt

Use with LM Studio

1. Open LM Studio: Program tab, then Install, then Edit mcp.json
2. Add the weather server (use absolute paths):

{
  "mcpServers": {
    "weather": {
      "command": "/absolute/path/to/.venv/bin/python",
      "args": ["/absolute/path/to/mcp_server.py"]
    }
  }
}

See mcp.json.example for a template.

3. Save. LM Studio will spawn the MCP server automatically.
4. In chat, enable tools and select a model that supports function calling.
5. Ask a question, for example:
   • Is a trip to the Polish seaside a good idea right now?
   • Czy wyjazd nad morze w Helu to dobry pomysł?

Recommended system prompt

For travel recommendations instead of raw weather data, paste the contents of prompts/travel_advisor.txt into LM Studio's System Prompt field.

Tool: get_weather

Parameter	Required	Description
city	yes	City name, e.g. Gdansk, Hel, Warsaw
country_code	no	ISO code, e.g. PL, DE, US. Always provide when known
region	no	Admin region to disambiguate similar city names

Example output

{
  "requested_city": "Hel",
  "requested_country_code": "PL",
  "requested_region": null,
  "resolved_city": "Hel",
  "resolved_region": "Pomerania",
  "country": "Poland",
  "country_code": "PL",
  "latitude": 54.60384,
  "longitude": 18.80351,
  "temperature_c": 17.2,
  "apparent_temperature_c": 16.2,
  "condition": "overcast",
  "humidity_percent": 90,
  "precipitation_mm": 0.0,
  "wind_speed_kmh": 20.0,
  "measured_at": "2026-07-13T14:30"
}

Project structure

.
├── mcp_server.py           # MCP tool server (LM Studio entry point)
├── mcp.json.example        # LM Studio config template
├── prompts/
│   └── travel_advisor.txt  # Optional system prompt for chat
├── requirements.txt        # Server dependencies
├── requirements-demo.txt   # CLI demo dependencies
├── example.env             # CLI demo environment template
└── examples/
    └── cli-agent/          # Optional Python agent demo

Optional CLI demo

A Python agent that connects to LM Studio via the OpenAI-compatible API and calls the MCP server programmatically.

pip install -r requirements-demo.txt
cp example.env .env
python examples/cli-agent/main.py "Is a trip to Hel, Poland a good idea?"

See examples/cli-agent/README.md for details.

Troubleshooting

Problem	Fix
Wrong city / weather from another country	Pass country_code (e.g. PL) when calling the tool
Model ignores the tool	Use a model with function calling; set temperature to ~0.1-0.2
MCP server not loading	Check absolute paths in mcp.json; ensure venv has deps installed
Region name mismatch	Translated names (e.g. Pomorskie vs Pomerania) are handled; retry with country_code

License

MIT. See LICENSE.