# Prototype

> Build a throwaway prototype to flesh out a design — a runnable terminal app for state/business-logic questions, or several radically different UI variations toggleable from one route.

- Skill: `connorgriffin/prototype` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add connorgriffin/prototype`
- Raw SKILL.md: https://api.skillmd.com/api/skills/connorgriffin/prototype/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ConnorGriffin (https://skillmd.com/u/connorgriffin)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/connorgriffin/prototype

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# 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 surrounding code, or by asking if the user is around:

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

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

### Prototype vs. ui-craft

The UI branch overlaps with the `ui-craft` skill — pick deliberately:

- **`ui-craft`** is a *pre-implementation* exploration. It produces standalone static HTML mockups, outside the app, screenshotted and iterated until a visual spec is **locked**. Reach for it when nothing is built yet and the deliverable is an agreed-on design.
- **`prototype`'s UI branch** produces throwaway *runnable* variants **inside the actual app**, wired to real routing, components, and data. Reach for it when the question can only be answered by real app behavior — interaction, live state, existing components under real content.

If you only need to see what it should look like, use `ui-craft`. If you need to feel how it behaves, prototype it in the app.

## Rules that apply to both

1. **Throwaway from day one, and clearly marked as such.** Locate the prototype code close to where it will actually be used (next to the module or page it's prototyping for) so context is obvious — but name it so a casual reader can see it's a prototype, not production. For throwaway UI routes, obey whatever routing convention the project already uses; don't invent a new top-level structure.
2. **One command to run.** Whatever the project's existing task runner supports — `pnpm <name>`, `python <path>`, `bun <path>`, etc. The user must be able to start it without thinking.
3. **No persistence by default.** State lives in memory. Persistence is the thing the prototype is _checking_, not something it should depend on. If the question explicitly involves a database, hit a scratch DB or a 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. The point is to learn something fast and then delete it.
5. **Surface the state.** After every action (logic) or on every variant switch (UI), print or render the full relevant state so the user can see what changed.
6. **Delete or absorb when done.** When the prototype has answered its question, either delete it or fold the validated decision into the real code — don't leave it rotting in the repo.

## When done

The _answer_ is the only thing worth keeping from a prototype. Capture it somewhere durable (commit message, ADR, issue, or a `NOTES.md` next to the prototype) along with the question it was answering. 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.