I think this is the key:

> To be fair neither is quite as complex as a whole 3D modeller.

Once you cross a certain complexity in your project, it becomes quite work intensive even using AI to do the coding. All the back and forth and cleaning up, exploring ideas and starting from scratch again takes time and effort and maybe most importantly, extensive human thinking. Just to clarify, I am not against AI and use it extensively myself. But vieb-coding all your tools is just not really a feasable idea for most (time/token-cost constraint) if you tools are of a certain complexity.

Actually I think "complexity" is probably not quite the right measure. You can vibe code very complex things, as long as they are in the "easy for AI" zone - clear goals, ideally non-graphically, ideally there's a specification or even better a reference implementation, best an automated way of checking correctness. CAD is about the worst case (and very complicated).

But you could easily vibe code, e.g. an H.265 decoder, even though it is super complex.