How to Create a Skill for Claude or Codex (No Coding Needed)

I kept pasting the same instructions into Claude: how I write a newsletter, what my brand colors are, “grill me on this plan until every question is answered.” Every new chat, same paragraph.

A skill means you teach your AI something once and it does it your way every time after.

If you’ve seen The Matrix, you already get it. Neo plugs the cable into his head and suddenly knows kung fu. That’s what a skill does for your AI.

What a skill actually is

A skill is a folder with one text file in it, called SKILL.md. The file says two things:

When to use it (a short description at the top).
How to do it (the instructions).

Think of the note you leave a dog sitter, with feeding times and what the dog isn’t allowed to eat. Load that note into your AI and you have the “how to take care of my dog” skill.

Your AI only reads the short description until a task matches it, and then it loads the full instructions. That’s why you can keep dozens of skills installed without filling up every chat.

Skills follow an open standard (agentskills.io), so the same folder works in Claude Code, the Claude app and Codex.

Step 1: pick the thing you keep repeating

My rule: if you do the same thing over and over, and it happens on a computer, it can be a skill.

Good first skills:

A brand skill: your logo, colors, fonts and tone in one place, so everything your AI makes comes out on brand. If you have a company or a personal brand, make this one first and give it to your whole team.
A writing skill for something you write every week, like a newsletter or a client update.
A tiny one. One of mine is about 10 lines and tells Claude to grill me on a plan until every question is answered.

Skills can also get big. My most popular, Diagram Design, started because I was tired of ugly AI diagrams, and it now has over 55,000 stars on GitHub. Another one edited my video about skills end to end. I give it raw footage and get back a finished video.

Step 2: let your AI build it with skill-creator

You don’t need to write the file yourself. There’s a skill called skill-creator whose whole job is making skills. You explain what you want, it asks you questions, and it writes the SKILL.md.

In Codex it’s built in. Type:

$skill-creator

It asks what the skill does, when it should trigger, and whether it needs scripts (the default is plain instructions).

In Claude Code, install it once from Anthropic’s official plugins:

/plugin install skill-creator@claude-plugins-official

Then say something like: “I want to make a skill that writes my weekly newsletter. Interview me.”

In the Claude app on a Mac, you can record one instead. In Cowork, click + in the message box, choose Record a skill, and do the task while you talk through it. Claude watches, then proposes a skill for you to review and save. (Pro, Max and Team plans. Don’t show passwords or private chats while you record.)

Step 3 (optional): write it by hand

If you’d rather see exactly what’s inside, a skill is just this:

brand-voice/
└── SKILL.md

And the file:

---
name: brand-voice
description: Apply Acme's brand (colors, fonts, tone) to anything public-facing. Use when writing copy, making slides, or designing graphics for Acme.
---

# Acme brand

## Colors
- Primary: #FF6B35
- Text: #2E2E2E

## Fonts
- Headings: Montserrat Bold
- Body: Open Sans

## Tone
Short sentences. Plain words. No hype.

## Always
- Use the full-color logo on light backgrounds, the white one on dark.

The description matters most, because your AI uses it to decide when to load the skill. Say what the skill does and when to use it, in the words you’d actually type.

Step 4: put it where your AI looks

Claude Code, in every project: ~/.claude/skills/brand-voice/SKILL.md
Claude Code, in one project only: .claude/skills/brand-voice/SKILL.md inside that project. Anyone who works in the project gets it too.
Codex, in every repo: ~/.agents/skills/brand-voice/SKILL.md
The Claude app: go to Customize > Skills and upload the folder as a ZIP.

I keep every skill in one folder, ~/.agents/skills/, which Codex already reads, and symlink it into ~/.claude/skills/ so Claude Code uses the same copy. That’s the setup from my .agents folder video. When my laptop died, I didn’t lose a single skill.

Step 5: test it

First call it by name: /brand-voice in Claude Code, $brand-voice in Codex.

Then check that it loads on its own. Ask for something the description covers, like “write a launch tweet for Acme,” without naming the skill. If it doesn’t kick in, the description is too vague, so rewrite it with the words you’d use when you ask.

When the output is off, ask your AI to update the skill file with the fix. Correcting only the reply means you’ll correct it again next week.

Don’t just download other people’s skills

There are thousands of free skills out there, but don’t blanket download them. Take one that’s close to what you need and change it to fit how you work, with your own examples and rules. The best skills are the ones that are specific to you.

Read any skill before you turn it on, especially if it comes with scripts. And never put passwords or API keys inside a skill file.

What a skill won’t do

A skill only knows what’s written in the file. When your process changes, update the file.

It won’t load if the description is fuzzy. Most of my “this skill doesn’t work” moments turned out to be description problems.

It doesn’t connect to your apps by itself. Pulling live data from Notion or Shopify needs a connector (MCP), and the skill tells the AI what to do with that data.

A skill also isn’t the same as CLAUDE.md. Claude reads CLAUDE.md at the start of every session, so use it for standing facts about a project. A skill loads only when it’s needed.

Checklist

Picked one thing I repeat
Built it with skill-creator (or wrote SKILL.md by hand)
Description says what it does and when to use it
Saved it where my tool looks
Called it by name, then checked it triggers on its own
No passwords or keys inside

New to the terms? nontechnical.dev/skill explains a skill in one picture. Want to build your first one with me? The free AI Native challenge has you make one.