OpenAI Function Calling API

Models generate structured JSON to call external functions (tools), enabling real-time data retrieval and action execution within a conversational flow.

The OpenAI Function Calling API, now formally 'Tool Calling,' empowers models like GPT-4 to interface with external systems. Developers define available functions using a `tools` parameter, including the function's `name`, `description`, and a JSON Schema for its arguments. When a user prompt requires external data (e.g., 'What is the stock price for AAPL?'), the model returns a structured `tool_call` object: `{"name": "get_stock_price", "arguments": {"ticker": "AAPL"}}`. Your application intercepts this call, executes the function, and returns the result to the model, which then synthesizes a final, grounded response for the user. This multi-step process ensures accurate, real-time information access.

https://platform.openai.com/docs/guides/tool-calling