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.
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.
npx agentmods add skills/nexu-io/open-design/web-prototypenpx skills add nexu-io/open-design --skill web-prototypegit clone --depth 1 https://github.com/nexu-io/open-designWrote 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.
[](https://agentmods.dev/skills/nexu-io/open-design/web-prototype)<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>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.
| Model | Per session | Once 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 |
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.
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)
- Read
assets/template.htmlend-to-end — at minimum through the<style>block. The class inventory at the top ofreferences/layouts.mdlists every class that must be defined there; if one is missing, add it to<style>rather than re-defining it inline on every section. - Read
references/layouts.mdso you know which section skeletons exist. Don't write a section type that isn't covered — pick the closest layout and adapt. - Read the active DESIGN.md (already injected into your system prompt). Map its colors to the six
:rootvariables 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.
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.
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.
- yesterday First seen · 102 lines · 59 tokens per session scan A 8f36016a362c
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.
Other skills, from other repositories
frame-flowchart-sticky
SVG 曲线连接 + 便利贴节点 + 光标交互, 像白板 brainstorm.
prototype-web
可点击的功能性 Web 原型, 含导航、英雄区、特性区、CTA.
motion-frames
可循环 CSS 动效组合: 旋转环、地球仪、计时器、视差标签.
saas-landing
单页 SaaS 落地页, 含 hero/features/social-proof/pricing/CTA.
waitlist-page
【模板: 等候名单页 / Waitlist】 【意图】为新产品 / 早鸟内测做一张极简等候页。 【布局】.
web-proto-brutalist
Swiss industrial-print 风: 单字 grotesque、巨数字、ASCII 装饰.