Skill Runtime in Agent Skills

Lessons in this section

1. Loading and Context Cost

   How agents load skills in three levels (catalog, one SKILL.md body, extra files on demand), and how to keep each level small: short descriptions, a minimum reliable workflow, and pointers to files.

2. Activation and Descriptions

   How agents find installed skills and pick one for a request: matching descriptions, writing what/when/when-not descriptions in users' words, fixing overlapping skills, calling skills by name and manual-only skills.