Function Calling

Function calling is an LLM capability that allows the model to output a structured request to invoke an external function or API. Instead of generating free text, the model produces a JSON object with the function name and arguments.

This is the technical foundation of tool use. When an agent needs to query a database or send a message, it does so through function calling. The host application receives the structured request, executes the function, and returns the result to the model.

Reliable function calling requires clear schemas and good prompt engineering. The OpsForEnergy agents use strictly typed function definitions with validation layers to catch malformed calls before they reach production systems.