OpenAI tool calling example

from json import loads
from signal import signal, SIGINT

from requests import get  # pip install requests
from openai import OpenAI  # pip install openai

# suppressing "KeyboardInterrupt" message
signal(SIGINT, lambda _, __: exit())


def get_weather(latitude, longitude):
    response = get(f"https://api.open-meteo.com/v1/forecast?latitude={latitude}&longitude={longitude}&current=temperature_2m")

    data = response.json()
    temperature = data['current']['temperature_2m']

    return str(temperature)


tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Get current temperature for provided coordinates in celsius.",
        "parameters": {
            "type": "object",
            "properties": {
                "latitude": {"type": "number"},
                "longitude": {"type": "number"}
            },
            "required": ["latitude", "longitude"],
            "additionalProperties": False
        },
        "strict": True
    }
}]

# OpenAI client and chat history with the first (system) message
client = OpenAI()
messages = [{"role": "system", "content": "You are a weather assistant."}]

while True:

    # sending message and getting a response back (chat completion)
    completion = client.chat.completions.create(model="gpt-4o-mini", messages=messages, tools=tools)

    # getting the first choice (is it possible to get more than one at a time?)
    choice = completion.choices[0]

    # appending the message to the conversation history
    messages.append(choice.message)

    # switch based on the finish reason
    match choice.finish_reason:

        # stop (weirdly) means we got a message response
        case "stop":

            # asking for the user for a prompt
            print("\nChatGPT:", choice.message.content)
            prompt = input("\nUser: ").strip()

            # appending the user message to the conversation history
            messages.append({"role": "user", "content": prompt})

        # in case we got a tool call
        case "tool_calls":

            # getting the first tool call (is it possible to get more than one at a time?)
            tool_call = choice.message.tool_calls[0]

            # function name and arguments
            function_name = tool_call.function.name
            arguments = loads(tool_call.function.arguments)

            match function_name:

                # calling the function and appending the result to conversation history
                case "get_weather":
                    result = get_weather(**arguments)
                    messages.append({"role": "tool", "tool_call_id": tool_call.id, "content": result})

                case unexpected_function:
                    raise Exception(f"Unexpected function call: {unexpected_function}")

        case unexpected_reason:
            raise Exception(f"Unexpected \"finish_reason\": {unexpected_reason}")

Running it:

ChatGPT: How can I assist you with the weather today?

User: whats the weather in ny right now

ChatGPT: The current temperature in New York is -2.9°C. If you need more information about the weather or forecast, just let me know!