web-prototype

web-prototype is a skill for Claude Code, Codex from nexu-io/open-design. It costs 59 tokens per session (1,286 once invoked), scanned A, original, Apache-2.0.

A general-purpose single-file HTML prototype for desktop websites, assembled from reusable page templates and layout sections. It is intended for landing pages, marketing sites, documentation, and SaaS interfaces.

In plain words
What is it for?
Use it to prototype landing pages, marketing pages, documentation sites, and desktop SaaS interfaces.
Why use it?
It gives common website types a ready structure so the work can focus on adapting content and layout.

Skill for Claude CodeCodex

About the project

OpenDesign is an open-source, local-first desktop app that lets coding agents create prototypes, dashboards, slide decks, images, video, and design systems as exportable files. It is used by people working with agent runtimes such as Claude Code, Codex, Cursor, and DeepSeek Harness. The catalogue add-ons extend the OpenDesign workflow with skills, instructions, commands, and plugins.

nexu-io/open-design · 94,103 stars · on GitHub

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/nexu-io/open-design/web-prototype
Any agent
npx skills add nexu-io/open-design --skill web-prototype
Clone the repo
git clone --depth 1 https://github.com/nexu-io/open-design

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for web-prototype

README.md
[![agentmods](https://agentmods.dev/badge/skills/nexu-io/open-design/web-prototype.svg)](https://agentmods.dev/skills/nexu-io/open-design/web-prototype)
Your own site
<a href="https://agentmods.dev/skills/nexu-io/open-design/web-prototype"><img src="https://agentmods.dev/badge/skills/nexu-io/open-design/web-prototype.svg" alt="Measured on agentmods" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,286 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00059 $0.01286
Opus 5 $0.00030 $0.00643
Sonnet 5 $0.00012 $0.00257
Haiku 4.5 $0.00006 $0.00129

Measured yesterday against content hash 8f36016a362c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

web-prototype scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

design-templates/web-prototype/SKILL.md · 102 lines

How it starts

The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Web Prototype Skill

Produce a single, self-contained HTML prototype using the bundled seed and layout library — not by writing CSS from scratch. The seed already encodes good defaults (typography, spacing, accent budget). Your job is to compose it.

Resource map

web-prototype/
├── SKILL.md                ← you're reading this
├── assets/
│   └── template.html       ← seed: tokens + class system + chrome (READ FIRST)
└── references/
    ├── layouts.md          ← 8 paste-ready section skeletons
    └── checklist.md        ← P0/P1/P2 self-review

Workflow

Step 0 — Pre-flight (do this once before writing anything)

  1. Read assets/template.html end-to-end — at minimum through the <style> block. The class inventory at the top of references/layouts.md lists every class that must be defined there; if one is missing, add it to <style> rather than re-defining it inline on every section.
  2. Read references/layouts.md so you know which section skeletons exist. Don't write a section type that isn't covered — pick the closest layout and adapt.
  3. Read the active DESIGN.md (already injected into your system prompt). Map its colors to the six :root variables in the seed; don't introduce new tokens.

Step 1 — Prepare index.html from the seed

Use assets/template.html as the seed for the canonical project file, normally index.html.

Replace the six :root variables with the active design system's tokens. Replace the page <title> and the topnav brand.

Step 2 — Plan the section list

Pick layouts before writing copy. Default rhythms (from layouts.md):

Page kind Default rhythm
Landing 1 hero → 3 features → 4 stats or 5 quote → custom split → 6 cta
Marketing / editorial 1 hero-center → 7 log list → 6 cta
Pricing 1 hero-center → 8 comparison table → 6 cta
Docs index 1 hero-center → 7 log list (sections of docs) → 6 cta

State the chosen list in one sentence to the user before writing — they can redirect cheaply now and not after 200 lines of HTML.

Read the full file on GitHub · 102 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 102 lines · 59 tokens per session scan A 8f36016a362c

Subscribe to this mod's changes

web-prototype is a skill published in the GitHub repository nexu-io/open-design (94,103 stars, last pushed today), licensed Apache-2.0. It adds 59 tokens to every session and 1,286 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.