Pretty cool, I made something similar (lambdaprompt[1]), with the same ideal of functions being the best interface for LLMs.

Also, here's some discussion about this style of prompting and ways of working with LLMs from a while ago [2].

[1] https://github.com/approximatelabs/lambdaprompt/ [2] https://news.ycombinator.com/context?id=34422917