What is Function Calling?

Function Calling

Definition A specific implementation of tool use where the AI model generates structured JSON to invoke a developer-defined function, enabling reliable integration between LLMs and application code. Function calling makes LLM outputs machine-parseable and action-ready.

In Depth

Developers define function schemas (name, description, parameter types) and pass them to the model. When the model determines a function is needed, it outputs a structured call rather than free text, ensuring predictable parsing. This pattern underpins customer service automation, coding assistants, database query generation, and any application requiring reliable data extraction from natural language input.

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