Guide the user through authoring a new agent skill — when a skill is worth creating, the SKILL.md format, progressive disclosure, and common pitfalls. Also covers discovering skill opportunities from the user's work patterns and generating a SKILL.md from a description. Trigger phrases include "create a skill", "write a skill", "make a skill", "new skill", "SKILL.md format", "how do skills work", "skill best practices", "convert this workflow into a skill", "what should I automate", and "find skill opportunities". Don't use it for invoking existing skills — only when authoring a new one or understanding the skill format.