Function calling

LLMs invoking tools/APIs.

Definition

Function calling (or tool use) lets LLMs invoke external functions or APIs — fetching live data, running calculations, calling databases. Powers AI agents and AI search.

Related terms

GEO

Generative engine optimization.

LLM

Large language model.

RAG

Retrieval-augmented generation.

llms.txt

File telling AI crawlers what your site is about.

Put Function calling to work

Build, publish, and rank your content with RankFlo. Free to start.

Start for free