Simon Willison’s Weblog

How to use a skill (progressive disclosure):

1. After deciding to use a skill, open its SKILL.md. Read only enough to follow the workflow.
2. If SKILL.md points to extra folders such as references/, load only the specific files needed for the request; don't bulk-load everything.
3. If scripts/ exist, prefer running or patching them instead of retyping large code blocks.
4. If assets/ or templates exist, reuse them instead of recreating from scratch.

Description as trigger: The YAML description in SKILL.md is the primary trigger signal; rely on it to decide applicability. If unsure, ask a brief clarification before proceeding.

— OpenAI Codex CLI, core/src/skills/render.rs, full prompt