Skills

The last chapter taught the agent to isolate work — push a noisy investigation into a subagent so it never crowds your main thread. This chapter teaches it something closer to a habit: a procedure you do over and over, written down once so the agent runs it itself the moment the situation calls for it. It’s the natural next step after rules. Rules are the standing facts about your project; a skill is a routine — a named, multi-step thing the agent does, not just knows.

A skill is a folder with a SKILL.md file in it. The frontmatter says when to use it; the body says what to do. Claude Code keeps every skill’s description in view, and when your request matches one, it pulls in the full instructions and follows them — no /command typed, no procedure re-pasted. You can still invoke one by hand when you want to; the new thing is that it can fire on recognition. Skills are documented on the skills page; this chapter walks the whole arc on one concrete procedure.

The ritual we’ll package

Same payments service. Every pull request on it ends the same way — a small, boring, non-negotiable ritual you’ve done a hundred times:

• run the test suite
• regenerate the API snapshot so consumers see the contract change
• add a line to the changelog
• check formatting before you push

It never changes. And every single time you either run the four steps by hand, or you re-type them at the agent — “okay now regenerate the snapshot, then update the changelog…” — as if it were the first time. That re-explaining is pure waste. The procedure is stable; only the PR is new. So we’ll write the ritual down once, as a skill, and let the agent recognize “this PR is ready to wrap up” and run the whole thing itself.

Across the next four lessons:

• Write the skill — the folder, the SKILL.md, the frontmatter and body — and walk the PR ritual end to end.
• Make it fire at the right time — the description is the trigger surface; you’ll tune it so the skill activates when you want it and stays quiet when you don’t, then prove it fires.
• Know when a skill is the wrong tool — skill vs slash command vs subagent, and which one a given job actually wants.

By the end, the four-step ritual is something the agent owns. You stop narrating it, and it stops being a thing you can forget a step of.

Start by writing the skill.