Simon Willison’s Weblog

Pushing ChatGPT's Structured Data Support To Its Limits. The GPT 3.5, 4 and 4 Turbo APIs all provide “function calling”—a misnamed feature that allows you to feed them a JSON schema and semi-guarantee that the output from the prompt will conform to that shape.

Max explores the potential of that feature in detail here, including some really clever applications of it to chain-of-thought style prompting.

He also mentions that it may have some application to preventing prompt injection attacks. I’ve been thinking about function calls as one of the most concerning potential targets of prompt injection, but Max is right in that there may be some limited applications of them that can help prevent certain subsets of attacks from taking place.