Gen AI — Function Calling

What is function calling?

Letting LLMs call external functions based on user input.

Define functions

tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Get current weather",
            "parameters": {
                "type": "object",
                "properties": {
                    "location": {
                        "type": "string",
                        "description": "City name"
                    }
                },
                "required": ["location"]
            }
        }
    }
]

Make API call

response = client.chat.completions.create(
    model="gpt-4",
    messages=[{"role": "user", "content": "Weather in Paris?"}],
    tools=tools
)

# Check for function calls
if response.choices[0].message.tool_calls:
    tool_call = response.choices[0].message.tool_calls[0]
    function_name = tool_call.function.name
    arguments = json.loads(tool_call.function.arguments)

Multiple functions

tools = [
    {
        "type": "function",
        "function": {
            "name": "search_products",
            "description": "Search for products",
            "parameters": {
                "type": "object",
                "properties": {
                    "query": {"type": "string"},
                    "max_price": {"type": "number"}
                }
            }
        }
    },
    {
        "type": "function",
        "function": {
            "name": "get_order_status",
            "description": "Check order status",
            "parameters": {
                "type": "object",
                "properties": {
                    "order_id": {"type": "string"}
                }
            }
        }
    }
]

Return results to model

messages.append({
    "role": "tool",
    "tool_call_id": tool_call.id,
    "content": json.dumps({"temperature": 72, "condition": "sunny"})
})

# Continue conversation with function results
response = client.chat.completions.create(
    model="gpt-4",
    messages=messages,
    tools=tools
)

Mini Practice

1. Define a function schema
2. Handle function calls
3. Return results to model
4. Build a multi-function assistant

Up Next

Continue with Multi-Modal - Working with images and text.