> soon to be outdated assumptions

Wild assumption. Having docs and code in step has never been easier.

> soon-to-be-outdated living and constantly modified AGENT file

Quite contradictory.

> I have absolutely seen far better initial project setups that are more complete, more focused, more holistically captured, and more utilitarian for the forthcoming evolution of design and system.

From a single dev, in a day's work? I call massive bs on this.