WHAT THIS PHASE PRODUCES
You leave with
- A working frontend-only prototype, scoped to the hypothesis
- A short build log of every shortcut you took on purpose
- A “delete plan”: what you will remove from the codebase before it tempts you to keep it
THE MENTAL MODEL
How to think about this phase
Create is a trap for founders who came from vibe-coding tools. The temptation is to keep building because the model keeps shipping. Resist it. The prototype exists to die.
Build only what is necessary to put the hypothesis under load. No backend you don’t need. No auth. No persistence beyond the single session a tester will spend with it. Every line you write that does not test the hypothesis is debt you will pay back next loop.
The right prototype is one a customer can hold for ninety seconds and form a real reaction to. If they need an onboarding tour, the prototype is doing too much. If you find yourself fixing edge cases nobody will hit during a session, you’re no longer in Create.
Keep a build log of the shortcuts you take. When the loop closes and you’re deciding whether to commit, that log tells you exactly what real engineering work the validated bet implies.
FREE AGENTS
Practice the Create phase in ChatGPT
Create phase · generate the build prompt
1-Shot App Prototyping Prompt
Describe your prototype in plain language or use voice input. Returns a precision prompt engineered for AI coding tools. Plain description in, copy-paste build prompt out.
Create phase · map the user flow
User Journey Map
Takes your target customer profile or discovery notes and maps how they move through the problem. Returns personas, journey maps, and documentation structured around the key moments for your prototype.
COMMON TRAPS
What goes wrong in this phase
- Adding scaffolding for the “next version” while you’re still validating the first one.
- Spending more than ninety minutes on visual polish before testing.
- Confusing prototype velocity with product progress. Speed of building is irrelevant if you’re building the wrong thing.
- Skipping the build log. You will forget what you skipped, and you will rebuild it badly later.
WHAT GOOD LOOKS LIKE
A worked example
SETUP
From the Plan example: the single-form first-draft PRD prototype.
OUTPUT
After Create: a one-page Next.js app deployed to Vercel. Form on the left, generated outline on the right, no persistence, no accounts, copy-to-clipboard button. A build log noting: “Hardcoded the prompt template. Skipped error states beyond a generic message. The retry button is a page reload. None of these are real product behavior; they’re here so I can ship in five hours and watch ten PMs use it.”