I've been building https://engine.build to introduce a proper structured external agent orchestrator that's used to build with clear constraints and make sure the end result is what you wrote in your spec or requirements. Without having to babysit and micromanage the models.

Implementation phases very often go through 5-10 review and fix rounds to actually get the implementation to match the spec. It takes longer but that's what's necessary to get actually good results on long horizon tasks with detailed requirements. I'll be open sourcing it fully soon.