Weather Agent MCP Server

A sample MCP server that provides weather information for a specified city using the OpenWeatherMap API.

Description

This project implements a simple Model Context Protocol (MCP) server called "Weather Bot". It exposes a single tool that fetches current weather data for a given city, including temperature in Celsius, humidity, and weather description. The server communicates via standard I/O (stdio) and can be integrated with MCP-compatible clients.

Tested on Apple M1 Air.

Features

Get current weather information for any city
Returns formatted weather data including description, temperature (°C), and humidity
Integrates with OpenWeatherMap API for up-to-the-minute weather data

Installation

Clone or download this repository to your local machine.
Install the required dependencies:
```
pip install -r requirements.txt
```

Configuration

Get an API key from OpenWeatherMap
Create a .env file in the project root and add your API key:
```
WEATHER_API_KEY=your_api_key_here
```
Security Note: Never commit your .env file to version control. Ensure it's included in your .gitignore.

Usage

Run the MCP server using:

python weather_agent.py

The server starts and listens for MCP protocol messages via stdio. It can be integrated with MCP-compatible applications or clients.

Integration with Claude Desktop

To test this MCP server with Claude Desktop, follow these steps:

Ensure Claude Desktop is installed on your machine.
Locate your claude_desktop_config.json file. On macOS, it's typically located at ~/Library/Application Support/Claude/claude_desktop_config.json. You can also open the path by openging via UI, Claude > Settings > Developer > Edit Config.
Open the claude_desktop_config.json file and add the following configuration inside the JSON object (add to the "mcpServers" object if it exists, or create it):

{
  "mcpServers": {
    "weather-agent": {
      "command": "python",
      "args": ["/path/to/your/mcp-server/weather_agent.py"]
    }
  }
}

Replace /path/to/your/mcp-server/weather_agent.py with the absolute path to your weather_agent.py file. For example, the path might be /Users/yourusername/Desktop/mcp-server/weather_agent.py.

Save the claude_desktop_config.json file.
Restart Claude Desktop to load the new configuration.
In Claude Desktop, you can now interact with the weather agent. For example, ask Claude: "What's the weather in Tokyo?" and it should use the MCP server to fetch and return the weather information.

Note: Ensure that your API key is configured in the .env file as described in the Configuration section, and that the Python environment is set up to run the script (e.g., the required packages are installed).

API

get_weather(city: str) -> str

Fetches current weather information for the specified city.

Parameters:

city: String - The name of the city to get weather for

Returns: A formatted string containing:

City name
Weather description
Current temperature in Celsius
Humidity percentage

Example Response:

The current weather in London is overcast clouds with a temperature of 15°C and humidity of 72%.

Dependencies

requests: For making HTTP requests to the weather API
python-dotenv: For loading environment variables from .env file
fastmcp: MCP server framework

Error Handling

If the weather API returns an error or the city is not found, the tool will return an error message indicating the failure to fetch data.

License

This is a sample project. Feel free to modify and use as needed.