Function Calling

What it is

Function calling is the technical mechanism that allows AI to use tools. The AI outputs structured data indicating which function to call and with what parameters. An external system executes the function and returns results. This is how AI interacts with the world beyond text generation.

Why it matters

Function calling is the bridge between AI reasoning and real-world action. When an AI "searches the web" or "runs code," it's using function calling. Understanding this helps you see how AI integrations work and what's happening behind the scenes in agent systems.