Guidance for adding and composing shadcn/ui components, which are reusable interface components copied into a project's own source code.

Use it to add, search, style, debug, and combine shadcn/ui components for forms, dashboards, settings pages, chat interfaces, and other screens.

It helps you find existing components, follow a consistent design system, and avoid rebuilding common interface patterns from scratch.

shadcn — Skill for Claude Code and Codex by fellipeutaka/leon

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.

Any agent

npx skills add fellipeutaka/leon --skill shadcn

Clone the repo

git clone --depth 1 https://github.com/fellipeutaka/leon

Made for: Claude Code, Codex.

Or install frontend, the plugin that ships this one along with the rest of its 35 skills.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/fellipeutaka/leon/shadcn/github.svg)](https://agentmods.dev/skills/fellipeutaka/leon/shadcn)

Your own site

<a href="https://agentmods.dev/skills/fellipeutaka/leon/shadcn"><img src="https://agentmods.dev/badge/skills/fellipeutaka/leon/shadcn/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/fellipeutaka/leon/shadcn"><img src="https://agentmods.dev/badge/skills/fellipeutaka/leon/shadcn.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 94 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,827 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 94% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.00094	$0.04827
Opus 5.5	$0.00038	$0.01931
Sonnet 5.5	$0.00019	$0.00965
Haiku 4.5	$0.00009	$0.00483

Measured 2mo ago against content hash a45cddd4511f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

shadcn 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 2mo 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.

Origin

This is a copy

94% identical to shadcn — 31 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.

skills/shadcn/SKILL.md · 276 lines

How it starts

The opening of the file, as written. The whole thing — 276 lines — stays where its author put it; the contents beside it link to each section on GitHub.

shadcn/ui

A framework for building ui, components and design systems. Components are added as source code to the user's project via the CLI.

IMPORTANT: Run all CLI commands using the project's package runner: npx shadcn@latest, pnpm dlx shadcn@latest, or bunx --bun shadcn@latest — based on the project's packageManager. Examples below use npx shadcn@latest but substitute the correct runner for the project.

Current Project Context

!`npx shadcn@latest info --json`

The JSON above contains the project config and installed components. Use npx shadcn@latest docs <component> to get documentation and example URLs for any component.

Principles

Use existing components first. Use npx shadcn@latest search to check registries before writing custom UI. Check community registries too.
Compose, don't reinvent. Settings page = Tabs + Card + form controls. Dashboard = Sidebar + Card + Chart + Table.
Use built-in variants before custom styles. variant="outline", size="sm", etc.
Use semantic colors. bg-primary, text-muted-foreground — never raw values like bg-blue-500.

Critical Rules

These rules are always enforced. Each links to a file with Incorrect/Correct code pairs.

Styling & Tailwind → styling.md

className for layout, not styling. Never override component colors or typography.
No space-x-* or space-y-*. Use flex with gap-*. For vertical stacks, flex flex-col gap-*.
Use size-* when width and height are equal. size-10 not w-10 h-10.
Use truncate shorthand. Not overflow-hidden text-ellipsis whitespace-nowrap.
No manual dark: color overrides. Use semantic tokens (bg-background, text-muted-foreground).
Use cn() for conditional classes. Don't write manual template literal ternaries.
No manual z-index on overlay components. Dialog, Sheet, Popover, etc. handle their own stacking.

Forms & Inputs → forms.md

Read the full file on GitHub · 276 lines

Files

What ships with it

15 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.

2mo ago First seen · 276 lines · 94 tokens per session scan A a45cddd4511f

Subscribe to this mod's changes

shadcn is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed yesterday), licensed MIT. It adds 94 tokens to every session and 4,827 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 94% identical to shadcn, differing in 31 lines, and is treated as a copy.

Frontend

shadcn next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
shadcnfellipeutaka/leon	Skill	5	yesterday	MIT	A	94	Claude Code, Codex
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code