pip install npiai

import os
import json
import asyncio

from openai import OpenAI
from npiai import FunctionTool, function


class MyTool(FunctionTool):
    name = 'Fibonacci'
    description = 'My first NPi tool'

    @function
    def fibonacci(self, n: int) -> int:
        """
        Get the nth Fibonacci number.

        Args:
            n: The index of the Fibonacci number in the sequence.
        """
        if n == 0:
            return 0
        if n == 1:
            return 1
        return self.fibonacci(n - 1) + self.fibonacci(n - 2)


async def main():
    async with MyTool() as tool:
        print(f'The schema of the tool is\n\n {json.dumps(tool.tools, indent=2)}')
        client = OpenAI(api_key=os.getenv('OPENAI_API_KEY'))
        messages = [
            {
                "role": "user",
                "content": "What's the 10-th fibonacci number?",
            }
        ]
        response = client.chat.completions.create(
            model="gpt-4o",
            messages=messages,
            tools=tool.tools,  # use tool as functions package
            tool_choice="auto",
            max_tokens=4096,
        )
        response_message = response.choices[0].message
        if response_message.tool_calls:
            result = await tool.call(tool_calls=response_message.tool_calls)
            print(f'The result of function\n\n {json.dumps(result, indent=2)}')


if __name__ == "__main__":
    asyncio.run(main())

python main.py