# Ce Prototype

Build a throwaway prototype to answer how something should work, feel, or read.

- Repository: https://github.com/EveryInc/compound-engineering-plugin (25818 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add EveryInc/compound-engineering-plugin --skill ce-prototype -g -a claude-code -y`
Codex: `npx skills add EveryInc/compound-engineering-plugin --skill ce-prototype -g -a codex -y`
Cursor: `npx skills add EveryInc/compound-engineering-plugin --skill ce-prototype -g -a cursor -y`
Gemini CLI: `npx skills add EveryInc/compound-engineering-plugin --skill ce-prototype -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add EveryInc/compound-engineering-plugin`

## Description

Build a throwaway prototype to answer how something should work, feel, or read. Use when committing the wrong answer would be expensive to unravel and a cheap sketch cannot settle it. Not a rough visual probe during brainstorming, not for deciding what to build, not polishing a feature that already works, not implementing the real thing.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Prototype

Build a throwaway prototype at the fidelity that can answer this question, before committing an approach later work will treat as given. Then apply the decisions or hand off.

**Do not fake the dimension being tested.** Modality, fidelity, and medium all follow from that one rule. A question about how a flow or state model behaves is settled by driving it, so a screen that only looks like the product does not answer it. A question about how a layout or a mark reads is settled by seeing it at real finish, so a thin sketch does not answer it either. The user's own perception settles the question, never your judgment of the artifact.

**Result:** the user decided how the product should work or feel against a prototype that did not fake what they were deciding.
**Next consumer:** an existing markdown Product Contract, or `ce-brainstorm` / `ce-plan` with this session as the seed.
**Done:** the user settled the questions that needed an artifact, or they apply and continue into brainstorm or plan. Their choice is the settlement, not a direction you inferred.
**Not:** a decision a cheap sketch settles, polish, or shipping the prototype as a final product.

If there is no person to experience the prototype, `mode:pipeline`, a headless run, or a calling skill that reports no human is present, stop. Do not start a preview or invent how it should feel. Return that this skill needs a human. A calling skill that has a human present (an interactive `lfg` run, for example) is an ordinary attended run.

**User-runnable invocation rendering.** The attended re-run in that refusal and the next-skill recommendation when the user applies print invocation syntax. Default to `/ce-prototype`, `/ce-brainstorm`, and `/ce-plan`; use `$ce-prototype`, `$ce-brainstorm`, and `$ce-plan` only on Codex or a host that documents dollar-prefixed skill invocation. Render only the invocation as inline code; output one form only.

## Scope the question

The rest: https://github.com/EveryInc/compound-engineering-plugin/blob/HEAD/skills/ce-prototype/SKILL.md