This is the meta-skill for building skills themselves. It teaches you how to structure modular extensions for Codex, balancing specificity with context efficiency. The core insight is treating the context window as shared resource: keep metadata lean (name and description trigger the skill), put workflows in SKILL.md (under 500 lines), and split heavy documentation into reference files that load on demand. It pushes you toward scripts for repetitive tasks and high specificity for fragile operations, but looser instructions when multiple approaches work. If you're creating skills or wondering why yours aren't triggering correctly, this explains the three-tier loading system and what belongs where.
npx skills add https://github.com/aiskillstore/marketplace --skill skill-creator