I think this is a very outdated perspective.

I don't plan things. I braindump context to the agent let it implement something, and iterate from there (A LOT).

Planning was for an era where implementation was expensive.

Implementation became cheaper but it’s still not cheap. I’m working on an implementation for a runtime that’s been going on for 4 months of 24/7 constant Sol and now Astra work. When things go wrong it costs my time, which is my most valuable commodity. A week spent going in the wrong direction is still a week. If I can avoid that by planning better I will.