I have used AI agents extensively for coding and my experience is that it's fine for prototypes, but in large projects like this there is risk that the codebase becomes unmaintainable.

This is a very popular opinion that is sort of obsolete now in my opinion.

It was a valid concern last year. We have seen tremendous progress on this in the last 4-6 months.

Even if your initial prototypes are unmaintainable slop, the state of the art models are fairly good at refactoring and fixing things.