Technology

OpenAI Function Calling

OpenAI Function Calling connects models (e.g., GPT-4) to external tools; it translates natural language requests into structured JSON objects for execution.

Function Calling (now Tool Calling) enables models to interface with external systems: you define available functions using a JSON schema. When a user prompt requires external data or action (e.g., 'what's the weather in Paris?'), the model returns a structured JSON object, not a final answer. This object specifies the function name and precise arguments (e.g., `get_current_weather("Paris")`). Your application executes this call, then sends the result back to the model. This two-step conversation allows the LLM to access real-time data, run code, or trigger API actions, significantly extending its capabilities beyond its training data.