How I Turn Ideas Into Products With AI Prompts

I'm an engineer. Before I build anything, I want to know what I'm building, who it's for and why.

So when AI tools showed up, I never just typed one line at them. I gave them what I'd give a new teammate: the full picture.

What surprised me was how rarely other people did. I kept seeing the same thing: someone types one line into ChatGPT, gets something generic back, and decides AI just isn't that good.

It is. It was just guessing.

The people getting great results from AI aren't using secret tools. They're just better at explaining what they want. That skill has a fancy name now, context engineering, but the idea behind it is simple, and anyone can learn it. I want to help more people get good at it, so this post is about the prompt I use to turn a rough idea into a clear plan for a real product, and why it works.

The AI is guessing, and it's a very confident guesser

Take a request like “Build me a habit tracker with reminders.” The AI will happily come back with a full plan, a feature list and a pile of code. To get there, it fills every gap with the most likely answer. Who's the app for? It guesses. What's the most important feature? It guesses. Phone or website? Free or paid? Guess, guess, guess.

The trouble is that it never tells you it's guessing. It answers in the same calm, confident voice it uses for everything. So you get something that looks finished but sits on a pile of assumptions you never agreed to.

That's what “context” means here: everything the AI needs to know to stop guessing. Your goal, your users, your limits, what you've already decided. Give it that, and the answers change completely.

Vibe prompting is fine, until it isn't

There's a popular way of working with AI that people call vibe prompting. You type whatever comes to mind, see what comes back, and nudge it until it looks right. No plan, just vibes.

For small things, it works fine. Rewriting an email, brainstorming names, explaining a confusing paragraph. (That's also what the Prompt Rulebook is for: quick copy-paste rules that make those everyday prompts better.)

But try to vibe your way from an idea to an actual product, and it falls apart. The AI forgets things you told it an hour earlier. It adds features you never asked for. It contradicts itself between messages. And because nothing is written down, you can't even tell whether the problem is the AI or you changing your mind.

The fix is to flip it around. Instead of telling the AI what to build, you let the AI ask you.

The prompt I start every project with

It's a free prompt from my AI Product Development Toolkit on GitHub. Its official name is the PRD prompt. PRD stands for Product Requirements Document, which is just a written plan: what you're building, who it's for and what it needs to do. I think of it as the brain-dump interview, because that's what it feels like.

You copy it, paste it into a good AI chat tool like ChatGPT, Claude or Gemini, and here's what happens.

1. You dump everything you've got

The prompt has a space where you paste your notes. All of them. Half-sentences, features you're unsure about, problems you've noticed, the thing your friend said over coffee. It doesn't need to be tidy. That's the point.

If you're staring at the empty space, run through these:

• Who is it for?
• What problem does it solve for them?
• Which features are you already picturing?
• What are your limits? Time, money, skills.
• What are you unsure about? Write that down too. The AI can help you decide.

Say you want to make a simple app for your book club. Your brain dump might be four lines: people forget which book we're reading, we never agree on a date, it would be nice to vote on the next book, and maybe share notes.

That's plenty to start.

2. The AI interviews you

This is where it gets different. The prompt tells the AI not to write anything yet. First it has to ask you the one to three most important questions.

For the book club, you'd get questions like these:

• How many people are in the club?
• Does everyone use a smartphone, or would some people prefer email?
• When you say “vote”, is it one vote each, or ranking a few books?

Questions you probably hadn't thought about yet. And every answer you give makes the next question sharper.

3. It checks in before it moves on

The prompt also tells the AI to stop and check with you whenever it's about to change topic or interpret something you said. You'll see things like:

My understanding is that members vote once a month and the book with the most votes wins. Is that right?

This is the part that saves you. A wrong assumption gets caught while it's still one sentence long, not after it has shaped the whole plan.

On top of that, the AI has to say its assumptions out loud, ask for numbers where numbers matter (“How many members do you expect in the first year?”), and point out when two things you said don't match.

4. You get a plan you actually agree with

Only when you agree that enough has been covered does the AI offer to write the document. It comes out in clear sections: the goals, who it's for, what people need to be able to do, what success looks like, and the questions you still need to answer.

For the book club, the goals part might read something like this:

Every member knows the current book and the next meeting date without asking in the group chat. The next book is picked by vote within one week, and at least 8 of 10 members vote.

Notice the numbers. They came from the interview, when the AI asked what success would look like. A one-line prompt would never have produced them, because the AI had no way to know.

It's a draft, not gospel. But it's your draft, built from your answers. And from then on, every AI conversation about the project can start from that document instead of one vague sentence.

What you can steal from this prompt, even if you never build an app

You don't need to be building a product to use the ideas behind this prompt. Here's what makes it work, and all of it carries over to everyday prompting:

• Give the AI your mess. Messy notes beat a neat one-liner. More context beats prettier context.
• Make it ask before it answers. Add “Before you start, ask me the questions you need answered to do this well” to almost any prompt.
• Make it say its assumptions out loud. “List any assumptions you're making” turns hidden guesses into things you can correct.
• One topic at a time. Big, sprawling conversations drift. Small steps that you confirm don't.

That's context engineering in plain English: give the AI what it needs to know, in an order it can handle, and check that it understood you.

A fair warning: this is not a shortcut

I want to be straight with you here, because the internet is full of “build an app in 10 minutes with AI” promises.

These templates are the opposite of that. They're systematic, and that takes time. The interview can go on for a while, and it will ask questions that make you stop and think. Sometimes you'll realize you don't know the answer yet. That's useful too.

If you use the toolkit, be ready for a deep dive. Treat it as a way to think your idea through properly, not as a magic button. The effort is still yours.

But the results can be wonderful. You come out with a clear plan, fewer surprises, and an AI that actually understands what you're building. For me, that trade is worth it.

One more thing: whatever the AI writes is a draft. Read it, fix it, and leave out private information you wouldn't want to share with an AI tool.

The rest of the toolkit, in one line each

The brain-dump interview is where I start, but the toolkit has more prompts that pick up where it leaves off. They all work the same way: the AI asks, you answer, it checks in.

• Ask real people first: builds a fair survey, so you can check that people want your idea before you build it.
• Map the screens: turns your plan into the steps and screens someone goes through when they use your product.
• Find the smallest useful version: cuts your idea down to the smallest first version worth building.
• Brief a design tool: turns your plan into a detailed prompt for an AI design tool.
• Plan your testing: makes a checklist to find out whether what you built actually works.
• Start fresh without losing progress: when a long chat gets confused, this turns it into a summary you paste into a new chat.

They're all free on GitHub.

Where to start

If there's an idea you keep coming back to, open the PRD prompt, paste in your notes, and let it interview you. Give it an evening. See what comes out.

And if you want to get better at the everyday prompts, the quick ones you type ten times a day, that's why I wrote the Prompt Rulebook. The free sample is a good place to start.