prototype

A prototype is throwaway code that answers a question. The question decides the shape.

Pick a branch

Identify the question — from the user's prompt, surrounding code, or by asking:

• "Does this logic / state model feel right?" → LOGIC.md. Tiny interactive terminal app that pushes the state machine through cases hard to reason about on paper.
• "What should this look like?" → UI.md. Several radically different UI variations on a single route, switchable via URL search param + a floating bottom bar.

The two branches produce very different artifacts — getting this wrong wastes the whole prototype. If genuinely ambiguous and the user isn't reachable, default to whichever matches the surrounding code (backend module → logic; page or component → UI) and state the assumption at the top of the prototype.

Rules that apply to both

1. Throwaway from day one, and clearly marked as such. Locate the prototype next to the module/page it's for so context is obvious — but name it so a casual reader sees it's a prototype, not production. For throwaway UI routes, follow the project's existing routing convention; don't invent a new top-level structure.
2. One command to run. Whatever the project's task runner supports — pnpm <name>, python <path>, bun <path>. The user must start it without thinking.
3. No persistence by default. State lives in memory. Persistence is the thing the prototype is checking, not something it depends on. If the question explicitly involves a DB, use a scratch DB or local file with a clear "PROTOTYPE — wipe me" name.
4. Skip the polish. No tests, no error handling beyond what makes the prototype runnable, no abstractions. Learn fast, then delete.
5. Surface the state. After every action (logic) or variant switch (UI), print or render the full relevant state so the user sees what changed.
6. Delete or absorb when done. Once the prototype has answered its question, delete it or fold the validated decision into real code. Don't leave it rotting.

When done

The answer is the only thing worth keeping. Capture it somewhere durable (commit message, ADR, issue, or a NOTES.md next to the prototype) along with the question it answered. If the user is around, that capture is a quick conversation; if not, leave the placeholder so they (or you, on the next pass) can fill in the verdict before deleting the prototype.