Prompt checker for AI app builders
Paste a prompt before you send it to Lovable, Bolt, v0, Cursor or Claude Code. You'll see what's missing, why it matters, and a better version to copy. No account needed.
Needs work
0/100- Too short: missingSay what to build, where, and how you'll know it works. Two to six sentences is plenty.
- One job per prompt: missingAsk for one feature at a time. A prompt that builds the whole app makes the AI guess, and guesses cost credits to undo.
- No vague words: missingWords like "modern" mean something different to everyone. Say exactly what should change: a color, a size, a label, a step.
- Says where: missingName the page or screen, like "on the Bookings page", so the AI doesn't search your whole app.
- Says who it's for: missingSay who can see or use it, like "only logged-in owners". That stops data showing to the wrong people.
- Says when it's done: missingAdd a check: "Done when a new booking shows on the calendar." The AI can test against it, and so can you.
- Says what not to touch: missingAdd a line like "Don't change the sign-up flow or the payment page." It stops changes you didn't ask for.
A better version to fill in
Build me a booking app for dog walkers and make it look modern Where: [the page or screen] Who: [who can see or use it] Done when: [what you'll see when it works] Don't change: [pages or features to leave alone]
What the checker looks for
| One job | One feature per prompt. Whole-app prompts make the AI guess. |
| Where | The page or screen, so the AI doesn't search your whole app. |
| Who | Who can see or use it, so data doesn't show to the wrong people. |
| Done when | A check the AI can test against, and so can you. |
| Don't touch | What to leave alone, so nothing else changes. |
| No vague words | "Modern" or "cleaner" means something different to everyone. |
| The error | When something's broken: the exact message, and what you expected. |
A good prompt, for example
On the Bookings page, add a "Cancel booking" button next to each upcoming booking. When the owner clicks it, ask "Are you sure?", then mark the booking as cancelled and email the walker. Only the owner who made the booking can cancel it. Don't change the calendar or the payment flow. Done when a cancelled booking shows as Cancelled and the walker gets an email.
It does one thing, says where, says who may do it, names what to leave alone and ends with a check. More in How to write prompts for AI app builders.
Frequently asked questions
What makes a good prompt for an AI app builder?
One job, a place, and a check. Say what to build, on which page, for whom, and how you'll know it works. Add what it shouldn't touch.
Why do vague prompts cost more credits?
A vague prompt makes the AI guess. It often changes more than you meant, and every message you send to undo that costs credits too.
Does this checker use AI?
No. It checks your prompt against simple rules in your browser. Your prompt isn't sent anywhere.
Should I write one big prompt for my whole app?
No. Build one feature at a time, in a planned order, and test each one before the next. Flowmaps writes those per-feature prompts for you.