Prototype

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

Pick a branch

Identify which question is being answered — from the user's prompt, the codebase, or by asking:

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

If ambiguous and user is AFK, default to whichever matches the surrounding code (backend module → logic, page/component → UI). State the assumption at the top.

Rules (both modes)

1. Throwaway from day one. Name it so a reader knows it's not production: prototype-{slug}/, _proto_{name}.py, etc. Place it near the code it's prototyping, not in a separate top-level directory.
2. One command to run. Whatever the project uses — python, pnpm, bun, node. Zero setup steps.
3. No persistence. State lives in memory. If the question involves a database, use a scratch file with a clear "PROTOTYPE — wipe me" name.
4. Skip the polish. No tests, no error handling beyond what makes it runnable, no abstractions.
5. Surface the state. After every action (logic) or variant switch (UI), print/render the full relevant state so the user sees what changed.
6. Delete or absorb when done. Either delete it or fold the validated decision into real code — don't leave it rotting.

Logic mode

Build a minimal interactive terminal app:

• Present the state machine's current state
• Offer numbered actions the user can take
• Execute the transition and show the new state
• Focus on edge cases and transitions that are hard to reason about statically
• In-memory only — no files, no databases

UI mode

Generate 3+ radically different variations, not minor tweaks:

• All variations on a single route, switchable via ?variant=1, ?variant=2, etc.
• Add a floating bottom bar with variant labels for quick switching
• Each variation should represent a genuinely different design direction
• Use the project's existing framework/styles — don't introduce new dependencies
• If the project has no frontend framework, use vanilla HTML

When done

The answer is the only thing worth keeping. Capture it:

• What question was asked
• What the prototype revealed
• Which variant/approach won and why

Save this in the commit message, a brief note next to the prototype, or the conversation. Then delete the prototype code or mark it clearly for cleanup.