It depends, first I ask myself if this didn't exist would I vibe code it myself, if I would, then is this good enough, might as well save my time and tokens on checking than building from scratch. Personal projects wise

I ask it just to make a plan file

It's a pain in the ass if you're doing parallel planning on the same repo.

It's much easier when the harness itself "knows" about planning and does it properly without me holding its hand.

That won't do any of the things plan mode enforces

I believe it depends on which ones, the older gen or certain classes of antihistamines