Writing a Skill an Agent Will Actually Read
· 8 min read
CatalEx Engineering · Published July 7, 2026 · 09:00 UTC
A skill is a self-contained Markdown directive with a little YAML frontmatter on top, sitting in its own directory. That description makes it sound like documentation, which is exactly the trap. The interesting part is not what a skill contains. It's when the agent pays for it.
Here is the sentence we keep in our own skill registry, and it is the whole
design: a skill is a directive the agent reads on demand via a read_skill
tool, rather than something injected into every prompt — so the agent pays the
token cost only when the skill is actually relevant to the turn.