Chapter 06 · Power tools

Skills & subagents

Two ways to stop repeating yourself: skills package instructions you reuse, subagents are helpers Claude sends off to do side-work without cluttering your conversation.

Skills: your own slash commands

A skill is a folder with one file, SKILL.md, containing instructions. Put it in .claude/skills/ in your project and it becomes a command: /monthly-summary, /weekly-report, whatever you name it. Claude can also invoke a skill on its own when your request matches its description.

.claude/skills/monthly-summary/SKILL.md

---
name: monthly-summary
description: Build my end-of-month portfolio summary
---

1. Read the newest export in data/
2. Work out each position's gain or loss for the month
3. Update summary.html: the table, then a short plain-
   English recap (net of fees) with the top 3 movers
4. Show me a preview before calling it done

Now /monthly-summary runs that whole checklist, every time, the same way. The easiest way to make one:

✳

Skill or CLAUDE.md? CLAUDE.md is read every session, so keep it for always-true rules. Skills load only when needed, so they're the home for step-by-step workflows and occasional knowledge. Added a skill mid-session? /reload-skills picks it up.

Subagents: delegate the side-quests

Some jobs generate a mess: researching across dozens of files, digging through logs, comparing libraries. A subagent does that work in its own separate conversation and reports back just the answer, so your main chat stays clean and focused.

You rarely need to set anything up; Claude delegates on its own when it helps. You can also define specialists in .claude/agents/, one markdown file each:

.claude/agents/proofreader.md

---
name: proofreader
description: Check my writing for typos and awkward phrasing
---

You are a careful proofreader. Point out problems;
never rewrite without being asked. British spelling.

Manage them with /agents. A specialist can use a faster model, see only certain tools, and keep its own memory.

Which one, when?

You want…	Reach for
A rule that applies to everything, always	CLAUDE.md
A repeatable multi-step workflow you trigger	A skill
Messy research done off to the side	A subagent
Something to happen automatically, no exceptions	A hook (next chapter)

✳ Try it yourself

make me a skill called /tidy that finds unused files in this
project and asks me one by one whether to delete them