You've seen test-rot, specification rot, and documentation rot; we now introduce; prompt rot!
Cluttering the repo with out-dated, very wordy and quickly outdated prompts will just confuse any agent tasked with looking at the repo in the future. Keeping context windows down is a real limitation to good LLM output, and this workflow may work completely against it.
- A plan.md describing the project, main abstraction idea, end costumer, and so on is great; but it should be kept minimal and up-to-date with the repo.
- Block comments on top of source-files and functions are great, and already very useful to coding agents. I don't see a value to anything more than what is already typical best practice.
I wonder if instead of checking the prompts into the repo as files, a better idea would be to store them inside the commit messages.
If prompts are specifications for a change of the system's behavior, then it seems natural to manage them as changes and not as resources.
This would also keep them in the right "historical context" of the repo and avoid the "prompt rot" you were talking about.