# Prototype Builder

> Prototype builder

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

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# Prototype builder

Come to meetings with the thing itself, not a deck about it. Build the
smallest artifact that makes the idea judgeable.

## Procedure

1. **Load `brand/`** (voice, visual identity, `tokens.json`) and the
   relevant `strategy/` context. On-brand prototypes get judged on the idea;
   off-brand ones get judged on the wrong fonts.
2. **Create `playgrounds/YYYY-MM-DD-<slug>/`** containing:
   - The prototype itself. Default form: **a single self-contained HTML
     file** (inline CSS, brand tokens applied, no build step, no CDN) that
     opens in any browser. An email sequence is one page showing each email
     in sequence; an ad board is one page of variants side by side.
   - A `README.md`: the one-sentence idea, what feedback is sought, and
     "disposable: decision goes to memory/decision-log.md".
3. **Fake honestly.** Placeholder metrics, imagery, and quotes are fine if
   you label them as fake in-context (e.g. "[illustrative]"). Never
   fabricate a real customer's endorsement.
4. **After the meeting** (when told the outcome): log the decision via
   `log-decision`, then move the prototype folder to
   `playgrounds/_archive/`.

## Rules

- Never production: nothing in `playgrounds/` ships, gets published, or gets
  linked externally.
- Speed beats polish, brand beats speed: rough is fine, off-voice is not.