Claude Code Basics Lesson 31 of 46
What a Skill Is: A Procedure Written Once
- A skill is a procedure written once, that you call up with a single word.
- You don't code it: it's plain English text, just like the instructions.
- The difference from CLAUDE.md: that one weighs on you always, the skill only when it's needed.
- It can be started by you or by it, if it figures out it's the right moment.
The gap left by the last chapter
Permanent instructions work great for facts: how things are organized, what they're called, what shouldn't be touched. Short, always valid, always useful.
But you also have procedures: that twelve-step thing you do once a month, always in the same order, always the same way. Putting it in the permanent instructions would be a mistake: it would take up the table in every session, including all the ones where you're doing something else entirely.
You need a place where a procedure can sit ready without weighing on anything, and load only the moment it's needed. That place is the skill.
What it is, concretely
A skill is a sheet of instructions. A text file where you write, in plain English, how a certain thing is done: the steps, the order, what to check, what the right result looks like.
There's nothing to program. If you can explain to a colleague how to do something, you already know how to write a skill.
The difference from typing that same explanation into the chat is all right here: the skill stays, it has a name, and you call it up with a word instead of rewriting it every time.
Who starts it
You, by typing its name preceded by a slash — just like the commands you already know.
It, when it figures out from your request that this procedure is exactly what's needed.
The second is the more convenient and the more fragile: it depends on how you wrote a single line of the file. We get to that in two lessons, and it's the most important thing in this chapter.
What you actually use it for
To keep this from staying vague, here are a few examples of things that become skills in everyday work — none of them need a single line of code:
the way you put together the monthly recap for a client: which numbers, in what order, what to highlight;
the checks you run before sending out a document;
how you turn meeting notes into the format you use;
the procedure for archiving a finished job.
The criterion is always the same: I do this often, it has steps, and I want it to come out the same every time.
What's next
In the next lesson we create one: one folder, one file, two header lines. It takes five minutes, and not even all of them yours — because you can have it write the skill for you.
Did you get it?
Two minutes, no grade. Trying to answer — even getting it wrong — cements the concepts far more than rereading. Not in the mood? Skip it: the lesson still counts as complete.
What is a skill, technically?
It's text, not code. The difference from a request typed out by hand is that it stays there, has a name, and gets called up with a single word — by you or by it.
Why does a long procedure belong in a skill rather than in CLAUDE.md?
Permanent instructions cost you every single time; a procedure is only needed once in a while. The skill solves this by setting it aside: it's there, but it only weighs on you the moment you use it.
Who can start a skill?
Both paths are normal. And which one works better depends on a single line of the file — the description — which is the subject of two lessons from now.
Course Claude Code Basics -
Chapter 1 Introduction
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Chapter 2 What's Underneath
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Chapter 3 You Choose the Engine
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Chapter 4 First Time at the Controls
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Chapter 5 What You Let It Touch
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Chapter 6 What It Knows About You
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Chapter 7 Skills
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Chapter 8 How Many You Put to Work
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Chapter 9 What It's Connected To
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Chapter 10 Automating the Setup
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Chapter 11 Wrap-Up