TL;DR don't have your agent write skills using only its latent knowledge, otherwise you may as well not use a skill in the first place and let it summon that latent knowledge on the fly.
Not sure if this take is correct though. I suspect self-generated skills help the agent avoid having to "decompress" its latent knowledge, which might save tokens? idk, I am not an expert
Autogenerated content is good scaffolding, but then I have a rule where if I mark heading with "(by-human)" the section shouldn't be changed by LLM without permission.