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AI Glossary

Function calling

What is Function calling?

A feature of some LLMs that allows the model to output structured arguments for predefined functions, enabling it to trigger real-world actions — such as querying a database, making an API call, or sending an email — within an AI application.

Example in practice

A sales engineer building an AI assistant that can check live inventory would use function calling — the model decides when to call the inventory API and formats the request correctly without hardcoded logic.