In function calling, the developer provides the model with a list of available functions along with their parameter schema. The model then decides whether and with which arguments to call a function, and returns this as structured JSON. The application executes the function and passes the result back to the model. Function calling is the technical foundation that lets AI agents use tools such as weather lookups, databases, or booking systems.
Function Calling
Function calling is an AI model's ability to specify, in a structured way, which external function should be called with which parameters. This lets it trigger actions and access real data.