You have a prompt in a notes file. You paste it most weeks. That is the signal that it should become a skill — but not every prompt deserves the upgrade, and doing it badly makes things worse.
The promotion test
A prompt earns becoming a skill when three things are true: you use it more than monthly, the output is wrong in ways you have to correct by hand, and the corrections are consistent. Consistent corrections are the real signal — they mean the missing piece is instruction, not intelligence.
If the corrections vary each time, a skill will not help. That is a task where the model needs better context, which means a tool, not a longer instruction.
The conversion, step by step
Start from the prompt that already works. Take it from the library or your notes. Do not rewrite it from scratch; you are promoting something that has evidence behind it.
Move the variables into placeholders. A prompt has `<diff>` and `<schema>`; a skill describes where those come from in your project. "The diff comes from `git diff –staged`" is more useful than another instruction about quality.
Add the trigger and the refusal. When does this skill apply, and when should the agent not use it? Without the refusal, the skill will be applied to tasks it was never designed for.
Add the verification step. The prompt library's entries all assume a human checks the result. A skill is supposed to run without one, so it needs its own check.
What changes when it becomes a skill
A prompt you paste is one user's habit. A skill is a claim about how the team works. That difference has consequences: someone will disagree with step three, and that disagreement needs a place to live — usually a comment in the file and a note in the repo.
Expect the first version to be wrong in a specific way: too general. Skills written by one person tend to describe principles. The fix is to append examples of the actual corrections you made, which is the most useful content a skill can contain.
When a skill is the wrong tool
If the task needs live data, a tool is the answer. If the task needs a decision the model cannot make, a human approval point is the answer. If the task is one-off, the prompt in your notes is fine — not everything needs to be infrastructure.
Back to the curriculum, or browse the skill directory to see how other people structured theirs.