How It Works
Function calling
A way for an AI model to ask a program to run a specific action — look up the weather, search a database, send an email — by producing a structured request (the function's name plus its inputs) instead of plain text. The program runs it and hands the result back to the model.
Origin
The name was popularized by OpenAI when it added 'function calling' to its API in June 2023; the underlying idea of models using external tools was explored earlier in research such as Meta's Toolformer (2023).