The Description Decides Whether It Gets Used

In short

Of a skill, Claude sees only the name and description until it uses it.
So the description is the only thing it decides on to know if it's the moment.
It has to say what it does and when to use it, in your actual words.
Having a lot of them costs almost nothing: they only weigh in as a catalog line.

The catalog and the folders

Picture a filing cabinet. On your collaborator's desk there are no folders: there's the list, one line per folder — a name and a sentence about what's in it. When they need one, they go to the cabinet and pull out the right one.

Skills work the same way. At the start of the session, they're only shown the catalog: the name and description of each one. They don't read the body — the actual steps — until they use it.

It's the same mechanism as the automatic memory index: the index always, the chapter on demand. That's why you can have twenty without weighing anything down.

The consequence almost everyone gets wrong

If it doesn't read the body, then the decision is made on the description. On that alone.

That's why the thing that makes everyone angry happens: you wrote a beautiful skill, detailed, perfect — and it never uses it. The body can be a masterpiece: if the description doesn't tell it this is the moment, that masterpiece stays in the cabinet.

The description isn't the skill's cover: it's its only switch.

How to write a description that works

It has to answer two questions, not one:

What it does — concretely, not in the abstract.
When to use it — in what situation, with what words you'll actually find yourself using.

The second is the one almost everyone forgets, and it's the more important one. Look at the difference:

Vague: "Handles reports." — What does "handles" even mean? When? There's nothing to grab onto.
Precise: "Prepares the client's monthly summary: gathers the numbers, puts them in the standard format, flags the variances. Use when the topic is the monthly summary, month-end close, or client report."

Notice the last part: it has the words you'd actually use. If in your head that thing is called "month-end close," that word has to be in the description — otherwise the connection never fires.

When you don't need any of this

If you always launch a skill yourself, by naming it, the description matters a lot less: you already know when it's needed. The care you put into the description is for skills you want to kick in on their own at the right moment.

And if one that should kick in on its own never does, now you know where to look: it's not the body, it's that line.

What's next

You know what it is, you know how to create it, you know how to make it recognizable. In the next lesson we'll build a real one, starting from the most boring thing you redo every week.

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 does Claude see of a skill before it uses it?

Which description works better?

You have twenty skills installed. What do they cost you when you're not using them?

1
1. 1
2. 2
3. 3
2
1. 4
2. 5
3. 6
4. 7
3
1. 8
2. 9
3. 10
4. 11
5. 12
4
1. 13
2. 14
3. 15
4. 16
5. 17
6. 18
5
1. 19
2. 20
3. 21
4. 22
5. 23
6. 24
6
1. 25
2. 26
3. 27
4. 28
5. 29
6. 30
7
1. 31
2. 32
3. 33
4. 34
8
1. 35
2. 36
3. 37
4. 38
9
1. 39
2. 40
3. 41
10
1. 42
2. 43
3. 44
11
1. 45
2. 46