Making API Tool Calls Robust

In production, the currency server's convert_currency() tool should not hang if the exchange-rate API is slow or unreachable. To mitigate this, you'll implement a timeout to the request and ensure any failure returns a short, clear error message to the user instead of a raw exception.

An MCP server has already been instantiated and stored as the variable mcp.

This exercise is part of the course

Introduction to Model Context Protocol (MCP)

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Exercise instructions

Implement try-except logic that will attempt the API request, and gracefully fail if an error is returned by capturing the exception.
Add a timeout of 10 seconds to the requests.get() call so the request does not hang indefinitely.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

@mcp.tool()
def convert_currency(amount: float, from_currency: str, to_currency: str) -> str:
    """
    Convert an amount from one currency to another using current exchange rates.

    Args:
        amount: The amount to convert
        from_currency: Source currency code (e.g., 'USD', 'EUR', 'GBP')
        to_currency: Target currency code (e.g., 'USD', 'EUR', 'GBP')

    Returns:
        A string with the conversion result and exchange rate
    """
    url = f"https://api.frankfurter.dev/v1/latest?base={from_currency}&symbols={to_currency}"
    # Implement try-except to gracefully handle errors
    ____:
        # Add a 10-second timeout so the request does not hang
        r = requests.get(url, ____=____)
        r.raise_for_status()
        data = r.json()
        rate = data["rates"].get(to_currency)
        if rate is None:
            return f"Could not find exchange rate for {from_currency} to {to_currency}"
        return f"{amount} {from_currency} = {amount * rate:.2f} {to_currency} (Rate: {rate})"
    ____ requests.exceptions.RequestException as e:
        return f"Error converting currency: {e}"

print(convert_currency(10, "USD", "EUR"))

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