prototype Skill (mattpocock/skills) for Claude Code: What It Does and How to Install It

Builds a throwaway prototype to answer one design question: does this logic feel right, or what should this screen look like.

Installs: 1M; on skills.sh
Stars: 309.2K; on GitHub
Files: 3; besides SKILL.md
Updated: Nov 2026; last repo commit

prototype makes Claude build something small and disposable instead of debating a design on paper. It first decides which question you are asking. For a state model or logic question, it builds one HTML file you double-click and drive with buttons. For a "what should this look like" question, it builds several different UI variations on one route, switchable from a bar at the bottom.

It starts when you want to sanity-check a design. The code sits next to what it prototypes, is clearly named as a prototype, keeps state in memory and skips tests. When you are done, you keep the decision and move the prototype to a throwaway branch. It needs no API key.

Good for

Developers unsure whether a state machine or business rule is right
Designers and product people who want to compare several UI directions fast
Teams that want a non-developer to click through a logic demo

Install prototype

Claude Code

Copy this prompt.

Install the prototype skill in Claude Code. Run this command:

npx skills add https://github.com/mattpocock/skills --skill prototype

Then check that it loaded and tell me how to use it.

2
Paste it into Claude Code. It shows the change and asks before running it.

Requires Node.js.

From its listing on skills.sh. Source.

What's in the skill

When it loads

Build a throwaway prototype to answer a design question. Use when the user wants to sanity-check whether a state model or logic feels right, or explore what a UI should look like.

Sections in SKILL.md

Pick a branch
Rules that apply to both

Key facts

Author: Matt Pocock (mattpocock/skills)
License: MIT
Installs on skills.sh: 1,025,261 (Nov 2, 2026)
GitHub stars: 309,237 (whole repo, Nov 2, 2026)
Last commit: Nov 1, 2026 (repo)
Files it bundles: SKILL.md, LOGIC.md, UI.md, agents/openai.yaml
Starts: Can start when your request matches its description

What it includes

Decides whether the question is about logic or about look and feel
Pick a branch
One shareable HTML file with free-play buttons and guided walkthroughs
Write · Logic prototype (LOGIC.md)
Several radically different variations on one route, switched by a URL parameter
Write · UI prototype (UI.md)
Clearly named, one command to run, in-memory state, no polish or tests
Write · Throwaway rules
Shows the full state after every action or variant switch
Surface the state
Keeps the decision in real code and the prototype on a throwaway branch
Write · Capture it when done

From the official docs

Permissions

Low risk

What it can do

Read your data
Create and change things
Delete things
Read-only mode

Watch out for

Runs code it just wrote
The prototype is new code that you or the assistant run. State lives in memory by default; if the question involves a database it is told to use a scratch DB or a local file with a wipe-me name.
skills.sh audits
Gen Agent Trust Hub pass, Socket pass, Snyk pass. skills.sh

Technical details

Sign-in and keys	None. No account or API key.
Scopes	Writes throwaway code next to the module or page being prototyped Starts the prototype with a project command such as pnpm, python or bun Commits the prototype to a throwaway branch when you finish

Questions

What does the prototype skill do?

It builds throwaway code that answers one design question. Logic questions get a single HTML demo. Look-and-feel questions get several UI variations on one page.

How do I install it?

Use the install box at the top of this page. It bundles two guides, LOGIC.md and UI.md, which come with the install.

What does it build for a UI question?

Several very different variations of one screen on a single route. You switch between them with a URL parameter and a floating bar at the bottom.

Will the prototype end up in my main branch?

No. The skill says to keep only the validated decision on main and commit the prototype to a throwaway branch, with a pointer on the implementation issue.

Does it need an API key?

No. It writes code in your project and runs it with your usual task runner, such as pnpm or bun.

Is it safe?

It writes new files in your project, so use version control. skills.sh audits: Gen Agent Trust Hub pass, Socket pass, Snyk pass.

Information

updated Nov 2, 2026

Repository: mattpocock/skills
Folder: skills/engineering/prototype

mattpocock/skills skills.sh

Sources

Docs, issue trackers and discussions this page is built from.

Show all 3

prototype SKILL.md · github.com
prototype on skills.sh · skills.sh
mattpocock/skills · github.com