Keep a prompt library you will actually open

Almost everyone who uses AI regularly ends up building a prompt library. Almost nobody opens theirs twice. It usually becomes a beautiful document with folders, tags, version numbers and 47 prompts, roughly four of which you’ve ever used.

Mine works because it’s small and deliberately a bit ugly. Here’s the shape of it.

One file, not a system

A single note, in whatever app you already have open all day. No folders, no database, no tool you have to remember to sync. If reaching your prompts takes more than two taps, you’ll retype them from memory instead, badly.

Put the newest at the top and don’t sort it. Search is faster than structure when you’ve got a dozen entries.

Only save a prompt after it has worked twice

This is the rule that keeps the library honest. First time something works, it might be luck. Second time, it’s a pattern worth keeping. Everything else is just a thing you typed once.

The effect is that mine holds nine prompts, and I use seven of them most weeks.

Write each entry in three parts

Name it for the moment you’ll need it, not for what it does. “When a thread has gone on too long” beats “Thread summariser”. Then the prompt itself, with square brackets for the bits you swap. Then one line on what to watch out for.

WHEN: someone sends me a long document and I need to respond today.
PROMPT: Here’s a document. Give me the three decisions it’s asking of me, anything with a date attached, and the two paragraphs I should read in full. Quote them. Don’t summarise the rest.
WATCH: it sometimes misses requests buried in appendices, so skim the end.

That WATCH line is the part that makes a library better than your memory. It’s where you store the mistake you already made, so you don’t make it a third time.

Keep your standing rules separate

Have one block for how you want things written, and paste it under whatever you’re doing. Mine says British English, no em dashes, plain words, vary sentence length, no motivational endings. It’s boring and it saves a rewrite every single time.

Delete more than you add

Once a month, read the list and cross out anything you haven’t used. It feels wasteful and it isn’t. A short library gets opened, and a long one gets ignored, which makes the long one worth nothing at all.

If you can’t bear to delete, move old entries to the bottom under a heading called “graveyard”. You’ll never look, and that’s fine.

Share the good ones

The fastest way to improve your prompts is to send three of them to a colleague and ask what they’d change. You’ll learn more in that one exchange than from any list of tips, because they’ll use them in a way you’d never have thought of.

Start today with two entries. The prompt you used this week that worked, and the standing rules block. That’s a library. Everything after that is just maintenance, and there’s less of it than you think.

Which prompt would be first in yours?