TDD has always been flawed. Tests can't give you complete coverage, they are always incomplete. Though every time I say this people think I'm against tests. I'm just saying tests can't prove correctness. You'd have to be a lunatic to think they are proofs. Even crazier is having the LLMs write their own tests and think that that's proof. I'm sure it improves things, but proofs are a different beast all together.
Seems things still haven't changed in half a century
What he describes is like that. Just that the plan step is suggesting docs, not writing actual docs.