What "It Works" Actually Means
Worked Once, for You, on Your Machine
When you said "it works" at the end of the prototype weekend, you meant something specific, and it is worth spelling out exactly what. It worked once. It worked for you, a person who knows which button to press and in what order, because you watched the thing being built. It worked on your machine, with your settings and your fast connection. And it worked with friendly data: sensible names, valid email addresses, one booking at a time, entered by someone trying hard to make it succeed. None of that was cheating — it is what a prototype is for, and Vibecoding was right to call it a result. But every one of those conditions was quietly doing work. The demo's definition of "works" carries four hidden qualifiers, and a product gets to keep none of them. The rest of this lesson removes them one at a time.
- Worked once, not worked reliably — a single pass along a happy path
- Worked for you, the one person who knows exactly what to press
- Worked with friendly data, entered by someone hoping it would succeed
- None of this was cheating; all of it was quietly propping up the result
Strangers, Bad Phones and Wrong Input
A product's definition drops the qualifiers. It has to keep working — for strangers, on old phones with patchy signal, with input nobody would design for. Watch the groomer's page meet a real Saturday. Two owners tap the same ten o'clock slot within a second of each other; only one dog can be groomed, so the page must refuse one of them politely rather than promise both. A customer books in a second dog that was never registered, and the record has to mean something anyway. Someone's thumb double-taps the confirm button, and the product must recognise one intention rather than create two appointments. None of these people is doing anything wrong. They are simply strangers using the thing without you standing behind them — which is the entire point of having built it. A product is what remains after your presence is subtracted.
- Two owners after the same Saturday slot — one must be refused politely
- A booking for a dog the system has never met still has to mean something
- A double-tap is one intention, and must not become two appointments
- A product is what remains after your presence is subtracted
A Claim About Time and Strangers
"Works" turns out to be two different claims wearing the same word. The demo's claim is about a moment: at this instant, with me watching, it did the thing. The product's claim is about time and strangers: for months, for people I have never met, it kept doing the thing, including when they used it strangely. The gap between those claims is not closed by more building — adding the cancellation flow does nothing to make the double-tap safe. It is closed by deliberately going looking for the awkward cases and deciding, one by one, what should happen in each. That is a different activity from building. It is slower per line than watching AI generate screens, and it is where the real workmanship of this stage lives. The next lesson is about making those decisions hold for years without you re-checking them by hand every week.
- The demo claims a moment; the product claims months and strangers
- More screens do not close the gap — decisions about awkward cases do
- Each awkward case needs an answer chosen on purpose, not left to chance
- The decisions then need a way to hold without your weekly attention
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