OpenAI function calling (2023)
OpenAI added function calling to GPT-3.5 and GPT-4. Developers could describe tools in a request and get JSON arguments back, so a model could trigger code instead of only writing text.
Apps began using models to choose tools and fill parameters.
Tool calling became a standard part of LLM APIs.
The Decisions API pushes the same idea further: it scores bounded choices directly, without generating a text answer to parse.
