What is OpenAI Function Calling?

Large language models are programs trained on huge amounts of text to produce language, but on their own they can only write text: they cannot look up fresh data or take actions in other software. Tool use fixes this by letting a separate program watch the model's output for a special syntax, run the requested tool and feed the result back to the model. Function calling is OpenAI's version of this: a developer describes functions to the model, and the model can answer with a structured data object (in JSON, a standard text format for data) holding the arguments for calling one. OpenAI's documentation says it lets models interface with external systems and access data outside their training data. OpenAI announced it on June 13, 2023.

Written from primary sources and reference pages, and checked against them by an independent AI fact-checker. Drafted with AI assistance.