Comment by dishantsethi

We still write one, but it got a lot shorter as the models improved. The big up-front PRD stopped paying off.

Frontier models are great at filling gaps, and that's the problem, they decide on your behalf.

The plan mostly exists to close those decision gaps. It also helps review: teammates can push back on a 30-line plan in five minutes, but a 2k-line diff takes an afternoon.