MCP Server Demo

Instructions

Implementation Reference

• server.py:25-35 (handler)

  The get_exchange_rate tool implementation - decorated with @mcp.tool() and contains the handler logic that makes an API call to exchangerate-api.com to fetch exchange rates between two currencies

  @mcp.tool()
  def get_exchange_rate(from_currency: str, to_currency: str) -> float | None:
      """Obtiene la cotización entre dos monedas. Devuelve None si hay error."""
      try:
          response = requests.get(f"https://api.exchangerate-api.com/v4/latest/{from_currency}", timeout=5)
          response.raise_for_status()
          data = response.json()
          return data.get("rates", {}).get(to_currency)
      except Exception as e:
          print(f"Error al obtener cotización: {e}")
          return None

• server.py:1-9 (registration)

  Server setup and FastMCP initialization - creates the MCP server instance that registers the tool decorator used by get_exchange_rate

  from mcp.server.fastmcp import FastMCP
  import requests
  import os
  from dotenv import load_dotenv
  
  load_dotenv()
  
  # Create an MCP server
  mcp = FastMCP("Demo", host="0.0.0.0", port=int(os.getenv("PORT", 8000)))