All terms
Patterns
Tool Calling
Letting a model emit structured calls to external functions or APIs.
Definition
Tool calling (also function calling) is the capability where a model, given a list of available tools such as a calculator or a web search, outputs a structured request to use one — naming the tool and its inputs — instead of answering directly. The surrounding program runs the tool, returns the result, and the model continues. It is the foundation of agents and lets language models reach beyond their training data.