Creates, reviews, improves, tests, and packages Claude skills. Use when someone says "create a skill", "build a skill", "make a skill for", "write a SKILL.md", "design a skill", "update this skill", "improve this skill", "turn this workflow into a skill", or "package this skill". Also triggers when a user asks to run evals to test a skill, benchmark skill performance with variance analysis, or optimize a skill's description for better triggering accuracy. Covers standalone skills, MCP-enhanced workflow skills, and iterative test-measure-refine loops on existing skills.