The current generation of AI coding agents makes it surprisingly easy to create a "skill." Write a Markdown file. Add instructions. Give it a name. Put it inside .claude/skills/ . Done. Except it isn't. As soon as you build more than a handful of skills, a different set of problems appears: Which skill should activate? Why did two skills activate at the same time? Why did the agent ignore an important instruction? What belongs in a skill versus a rule, agent, hook, or script...