Claude Code Skills: What They Are and How I Use Them
Claude Code skills are saved instructions in a SKILL.md file. Claude uses one when your request fits, or you run it with a slash command. Here's how.
A Claude Code skill is a set of instructions you save once, in a file called SKILL.md. Claude uses it when your request matches what the skill is for, or you run it yourself by typing a slash and its name. You stop retyping the same instructions. That’s the whole idea.
Here’s what that looks like on an ordinary working day.
What problem do skills solve?
Picture the third time this week you start the same job. You open Claude Code in your project folder. Then you type the rules again.
Keep the sentences short. Use these two colours. Check every link before you call it done. Don’t touch the contact form.
You typed nearly the same paragraph on Monday. You’ll type it again on Friday. And one day you’ll leave a line out, and the work will come back wrong.
A skill is that paragraph, saved in a file. Next time you type /page-check, or whatever you named it, and Claude follows every line. Or you just ask for the job in plain words, and Claude spots that the skill fits.
What is a skill, exactly?
A folder with one required file inside it, SKILL.md. The file has two parts. A short header between two --- lines, then your instructions in plain English.
Here’s a small one:
---
description: Checks a web page before launch. Use when I ask to review, check or proof a page.
---
1. List any spelling mistakes on the page.
2. Check that every link works.
3. Confirm the page has exactly one main heading.
4. Report what you found. Don't fix anything until I say so.
Save it in a folder called page-check and the folder name becomes the command: /page-check. You can add a name line to the header if you want a different command name.
Where do skills live?
Where you save the folder decides where the skill works.
| Type | Where the file goes | Works in |
|---|---|---|
| Personal | ~/.claude/skills/page-check/SKILL.md | Every project on your computer |
| Project | .claude/skills/page-check/SKILL.md inside the project | That project only. Commit it and your team gets it too |
| Plugin | Inside an installed plugin | Wherever the plugin is turned on |
On Windows, ~ means your user folder, C:\Users\YourName.
Type /skills inside Claude Code to see every skill you have.
How does Claude know when to use one?
It reads the description. In every session, Claude sees each skill’s description, not the whole file. The full instructions load only when the skill is used.
That has two effects. A long skill costs almost nothing until you need it. And the description is the most important line you’ll write.
Say what the skill does and when to use it, in the words you’d actually type. “Checks a web page before launch” plus “use when I ask to review a page” beats “page helper.”
Can you stop Claude running a skill on its own?
Yes. Add disable-model-invocation: true to the header. Now it only runs when you type the command yourself.
Use that for anything with side effects, like publishing or deploying. You don’t want those starting because Claude guessed.
It works the other way too. user-invocable: false hides a skill from the slash menu, so only Claude can use it. That suits background knowledge you never need to call by hand.
How do you make your first skill?
Three steps.
- Make the folder:
~/.claude/skills/page-check/ - Save a SKILL.md inside it with a description and your instructions.
- Start Claude Code and type
/page-check, or ask for the job in plain words.
No restart needed. Claude Code watches your skills folders and picks up new and edited skills in the session you’re already in.
You can also ask Claude Code to write the file for you. Describe the job, tell it where to save the skill, and read what it wrote before you use it.
Are skills the same as slash commands?
They’ve merged. An old command file at .claude/commands/deploy.md and a skill at .claude/skills/deploy/SKILL.md both give you /deploy. Old command files still work.
Skills add two things. A folder for extra files, like examples or a script. And the option for Claude to pick the skill up on its own.
Built-in commands like /help and /compact are different. They run fixed actions, not your instructions.
Claude Code also ships with a few skills ready to use. /doctor, for one, checks your setup and offers fixes.
How I use skills
I build websites for local businesses with Claude Code, and I use it every day. When you build the same kind of thing again and again, the repeat jobs are the ones worth saving.
A good rule to start with: if you’ve typed the same instructions twice, make them a skill.
Don’t build a skill for a job you’ve done once. You don’t know the steps yet, so you’ll save the wrong ones.
Frequently asked questions
Do Claude Code skills cost extra? No. Skills are part of Claude Code, which comes with Claude’s paid plans from Pro at $20 a month. The free plan doesn’t include Claude Code. Here’s what each plan costs.
Where do I put a Claude Code skill?
In ~/.claude/skills/<skill-name>/SKILL.md to use it in every project. Or in .claude/skills/<skill-name>/SKILL.md inside one project to keep it there.
What’s the difference between a skill and CLAUDE.md? CLAUDE.md is read at the start of every session, so it’s for facts Claude always needs. A skill’s instructions load only when the job comes up, so it’s for procedures.
Do Claude Code skills work in the Claude app? Claude Code skills follow an open standard called Agent Skills. You can upload one to claude.ai, but Claude Code-only features, like running a command inside the skill, won’t work there.
New to all this? Start with What Is Claude Code? and How to Install Claude Code, or watch my free video, where I build a real site with Claude Code start to finish. Watch the free video.