Borrowing it
Nothing to install: this file belongs to forbiddenlink/mythos. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/forbiddenlink/mythos/main/.agents/skills/shadcn-ui/SKILL.mdgit clone --depth 1 https://github.com/forbiddenlink/mythosWrote 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/forbiddenlink/mythos/shadcn-ui)<a href="https://agentmods.dev/skills/forbiddenlink/mythos/shadcn-ui"><img src="https://agentmods.dev/badge/skills/forbiddenlink/mythos/shadcn-ui/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/forbiddenlink/mythos/shadcn-ui"><img src="https://agentmods.dev/badge/skills/forbiddenlink/mythos/shadcn-ui.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00073 | $0.09880 |
| Opus 5.5 | $0.00029 | $0.03952 |
| Sonnet 5.5 | $0.00015 | $0.01976 |
| Haiku 4.5 | $0.00007 | $0.00988 |
Grade A, and why
shadcn-ui 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 1mo ago.
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.
This is a copy
86% identical to shadcn-ui — 491 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 1,617 lines — stays where its author put it; the contents beside it link to each section on GitHub.
shadcn/ui Component Patterns
Expert guide for building accessible, customizable UI components with shadcn/ui, Radix UI, and Tailwind CSS.
Table of Contents
- When to Use
- Quick Start
- Installation & Setup
- Project Configuration
- Core Components
- Advanced Patterns
- Customization
- Next.js Integration
- Best Practices
- Common Component Combinations
When to Use
- Setting up a new project with shadcn/ui
- Installing or configuring individual components
- Building forms with React Hook Form and Zod validation
- Creating accessible UI components (buttons, dialogs, dropdowns, sheets)
- Customizing component styling with Tailwind CSS
- Implementing design systems with shadcn/ui
- Building Next.js applications with TypeScript
- Creating complex layouts and data displays
Quick Start
For new projects, use the automated setup:
# Create Next.js project with shadcn/ui
npx create-next-app@latest my-app --typescript --tailwind --eslint --app
cd my-app
npx shadcn@latest init
# Install essential components
npx shadcn@latest add button input form card dialog select
For existing projects:
# Install dependencies
npm install tailwindcss-animate class-variance-authority clsx tailwind-merge lucide-react
# Initialize shadcn/ui
npx shadcn@latest init
What is shadcn/ui?
shadcn/ui is not a traditional component library or npm package. Instead:
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.
- 1mo ago First seen · 1,617 lines · 73 tokens per session scan A f73889c829b6
shadcn-ui is a skill published in the GitHub repository forbiddenlink/mythos (2 stars, last pushed 2d ago), licensed MIT. It adds 73 tokens to every session and 9,880 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 86% identical to shadcn-ui, differing in 491 lines, and is treated as a copy.
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magic-ui
Use this skill when users want to add, customize, or troubleshoot Magic UI components in React/Next.js projects. It covers component selection, shadcn registry installation (@magicui/), integration patterns, and practical quality checks for accessibility and maintainability.
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system-design-diagramming
Draw system diagrams in the Archify visual language: a typed JSON spec rendered as dark-canvas SVG with numbered lanes, semantic node colors, masked edge labels, and a legend. Covers architecture, workflow, sequence, dataflow, and lifecycle views. Use for any design-session diagram.
common-stitch-design
Drive Google Stitch over MCP safely - read screens, write and lint DESIGN.md, create design systems, and fix designs through variants instead of overwriting. Use when reviewing, editing, or generating Stitch screens or DESIGN.md files.
common-ui-design
Design distinctive, production-grade frontend UI with bold aesthetic choices. Use when building web components, pages, interfaces, dashboards, or applications in any framework (React, Next.js, Angular, Vue, HTML/CSS).