linbiaowen/mcp-server-sample

MCP Crypto Price Server

This is a simple MCP server exposing a tool to get the current price of a cryptocurrency in a specified currency using the CoinGecko API.

Setup

1. Clone this repo or copy the files.
2. Install dependencies:

   pip install -r requirements.txt
   

3. Set up your CoinGecko API key:
   • Get your API key from CoinGecko.
   • Preferred: Edit api_key.txt and put your API key in it using the following format (key=value):

     COINGECKO_API_KEY=your_actual_api_key_here
     

   • Alternative: If api_key.txt is missing or empty, you can set the COINGECKO_API_KEY environment variable:

     export COINGECKO_API_KEY=your_actual_api_key_here
     

   • Priority: The server will use the key in api_key.txt if present and non-empty. Only if that file is missing or empty will it use the environment variable.

Running the Server

You can run the server in dev mode (recommended for local testing):

uv run mcp dev server.py

Or run directly:

python server.py

Usage

The server exposes a tool:

• get_crypto_price(crypto_id: str, currency: str = "usd") -> float

Example call:

• get_crypto_price("bitcoin", "usd") # returns BTC price in USD
• get_crypto_price("ethereum", "eur") # returns ETH price in EUR

Notes

• Requires a valid CoinGecko API key. The server will use api_key.txt (in key=value format) if present and non-empty, otherwise it will use the COINGECKO_API_KEY environment variable.
• See CoinGecko API docs for valid crypto IDs and currencies.