One thing I'd like to critisize - although I can agree that skill security is a real problem, but the solution is not to restrict yourself from using them, but to rely on the community: reviews, likes/dislikes, maybe having the skills curated. We need some trust signals. Also, since markdown files are auditable by design - your agent might actually verify them before running - provided you're using something like GPT-5.4 on high reasoning.