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The prompt that tells you when your app fails

How do you find out that your app is broken before a customer tells you?

Last checked 2026-09-24

Ask what could fail silently, and make each of those tell you. Most small apps have no idea anything is wrong until someone complains — and most people do not complain, they leave. An email to yourself is enough to change that.

The prompt

List everything in this app that could fail without anyone noticing — a failed save, an email that did not send, a payment that succeeded but delivered nothing. For each one, add something that tells me: an email to my address, or a visible error. Do not add a monitoring service.

When to use itThe week you launch, before you have users rather than after.
Why it is worded that waySilent failure is the expensive kind. A visible error costs you one annoyed user who tells you; a silent one costs you every user it touches and you never learn. The last clause keeps the fix proportionate — at this size you need to be told, not to have a dashboard you will not open.

Start with the money path

Payment succeeded and delivery failed is the one failure that is worse than being down, because the customer has paid and is waiting. If you alert on one thing, alert on that.

Send it to yourself, not to a system

An email in your inbox gets read. A log line in a dashboard does not. Sophistication can come later, when the volume makes an inbox impractical — which is a good problem.

Check it actually arrives

An alert you have never seen fire is a hope. Break something on purpose once and confirm the message reaches you, because alerting that was never tested is the most common kind of alerting there is.

The Build Prompt Pack

This is one of 57 prompts, from the phase "The week after launch". The pack has the rest, each with the same reasoning underneath, plus the research they are built on and a house-rules file you paste in once.

Get the pack — €9

Tools this applies to

ToolWhat it doesPrice
ResendTransactional email that actually arrives.Free tier
VercelHosting. Puts a project live on a real address with one command.Free tier
PlausibleSimple, privacy-friendly visitor stats with no cookie banner.~€9/mo
UmamiSame idea, free if you host it yourself.Free self-hosted

Every tool has its own page with what it costs and who should skip it. Some links are affiliate links.

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Why does an AI-built app look broken when there is no data yet?

The whole library

All prompts →The packs →