Thanks for the writeup!
I talked about a similar, but slightly simpler workflow in my post on "Vibe Specs".
https://lukebechtel.com/blog/vibe-speccing
I use these rules in all my codebases now. They essentially cause the AI to do two things differently:
(1) ask me questions first (2) Create a `spec.md` doc, before writing any code.
Seems not too dissimilar from yours, but I limit it to a single LLM
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