I'm enough of a type-safety bigot that I would have started with schema-first, as I want schemas for all the things. :-) FWIW, I would suggest avoiding the (IM

I'm enough of a type-safety bigot that I would have started with schema-first, as I want schemas for all the things. :-) FWIW, I would suggest avoiding the (IMO) mistake of using your markup language for the schema. E.g. like json-schemas where we need a "properties" map, "type": "string" (how many times do I have to type "type"), all sorts of syntactical overhead. Personally, I think IDLs are much cleaner, as you can design a purpose-specific grammar. More work up front, and you don't get a parser for free, but again personally I think it's more pleasant in the long-run for developers to read and write. Granted, not sure how that jives with your lisp/etc. way of thinking, but my two cents. Good luck!