miniblog.

I think you could build an interesting IDE with a tiny embedded LLM in addition to the usual tooling. Features like 'extract method' would be much nicer if an LLM could provide a name. Choosing a good name is virtually impossible from just a typed AST.

I've seen markdown projects leverage link syntax for custom extensions, e.g. [click me](button://). Markdown also supports embedded HTML. Perhaps you could add custom tags for extensions?

Coalton is a remarkable ocaml-style language embedded in Common Lisp: https://github.com/stylewarning/coalton/ It includes a static type checker too!