Write the Check Before You Write the Prompt

One sentence, ninety seconds, before you touch the prompt box again.

It’s mid-morning on a Tuesday, nothing special about it. You’ve got a new feature to build, a customer-facing settings page this time, and you’re doing what you always do. Laptop open, coffee going cold, the cursor blinking in the prompt box like it’s waiting for you to just get on with it.

You start typing the way you always start typing. “Build a settings page where customers can update their email, password, and notification preferences.” Reasonable. Complete-sounding. Your hands know this rhythm by now, forty words in, hit enter, watch something appear.

Your fingers stop half an inch from the keyboard.

You’re thinking about the demo. Not the good kind of thinking, the kind where your stomach tightens a little before your brain even catches up to why. You’re back in that room, the client’s laptop turned toward you, everyone leaning in to watch the thing you’d built work exactly the way it had worked every single time you’d clicked through it yourself. And then the client clicked somewhere you hadn’t. One tap you’d never happened to make. The room went quiet in that specific way rooms go quiet, not loud, not dramatic, just a held breath and a flat, unreadable look you’ve thought about more times since than you’d like to admit.

You’d driven home that night replaying it, trying to figure out what you’d have to be smarter about to make sure it never happened again. You still don’t have a good answer to that. But you’re staring at this half-typed prompt now, and something about it feels like the exact same shape as the sentence that got you into that room in the first place. Complete-sounding. Untested against anything but your own imagination.

So you stop.

You open a blank note instead, off to the side, and you write one line. Not a spec. Not a doc anyone would ever call a requirements document. Just one sentence that has to answer two things at once: what does “working” actually mean here, and what’s one way this breaks that you’d want caught this morning, at your kitchen table, instead of in front of someone whose face you’ll remember for a year.

“Customers should be able to update their email, password, and notification preferences, and if they submit a password that doesn’t meet the minimum requirements, the page should tell them clearly and save nothing else on the form.”

You read it back. Ninety seconds, maybe less. Something in your chest loosens a little, the specific relief of finally knowing what you’re actually asking for instead of what you’ve been picturing.

Now you go back to the prompt box, except it’s different this time. The sentence sits open in the other window, and you write with it in view, checking your own request against it every few words instead of against memory alone. You even catch yourself softening a line you’d have left vague before: not just “update their preferences” but the version that admits preferences can be submitted wrong.

The AI builds the page. And here’s the part that used to be the whole test: it works. Clean load, fields populate, everything looks right.

Old you would have called that done. Three clicks, no errors, ship it.

This morning you don’t. You go looking, on purpose, for the exact thing your sentence said shouldn’t happen. You type a six-character password into a field that wants eight. You hit submit and hold your breath a little, the same held breath from that room, except this time you’re the only one watching.

The page stops you. Tells you clearly. Saves nothing else.

It caught it. Not the AI catching it on its own, and not you catching it by accident three weeks from now when a real customer finds it first. You caught it, this morning, because you’d written down what “working” meant before you ever asked for it.

You didn’t get smarter between the demo and this morning. You didn’t learn to code. You wrote one sentence before the prompt instead of finding out after the screenshot, and that turns out to be most of the difference that matters.

Try it on whatever you touch next. Before the prompt, not after the mistake: one sentence, what “working” looks like, and one way it breaks that you’d rather find yourself.

It won’t catch everything. It’s not supposed to. It’s just the first thing you write now, every time, before anything else.

Next week, we hand you something that does more of this thinking with you.

P.S. If you’ve ever come across Matt Pocock’s stuff, he teaches developers, mostly TypeScript, you’ve probably already seen a version of this same idea. Developers have their own word for it and their own tools for doing it. You don’t need to be one to use it. You just needed someone to hand you the version that doesn’t assume you already speak the language.