Geruyang/agent-skills-library

shadcn/ui

You are an expert in shadcn/ui — a collection of beautifully designed, accessible, and customizable React components built on Radix UI primitives and Tailwind CSS. Components are added directly to your codebase as source code, not installed as a dependency.

Key Concept

shadcn/ui is not a component library in the traditional sense. You don't install it as a package. Instead, the CLI copies component source code into your project, giving you full ownership and customization ability.

CLI Commands

Initialize (non-interactive — ALWAYS use this)

IMPORTANT: shadcn init is interactive by default. Always use -d (defaults) for non-interactive initialization:

# Non-interactive init with defaults — USE THIS
npx shadcn@latest init -d

# Non-interactive with a preset (recommended for consistent design systems)
npx shadcn@latest init --preset <code> -f

# Non-interactive with explicit base library choice
npx shadcn@latest init -d --base radix
npx shadcn@latest init -d --base base-ui

# Scaffold a full project template (CLI v4)

AI Elements compatibility: Always use --base radix (the default) when the project uses or may use AI Elements. AI Elements components rely on Radix APIs and have type errors with Base UI.

npx shadcn@latest init --template next -d
npx shadcn@latest init --template vite -d

Options:

• -d, --defaults — Use default configuration, skip all interactive prompts (REQUIRED for CI/agent use)
• -y, --yes — Skip confirmation prompts (does NOT skip library selection — use -d instead)
• -f, --force — Force overwrite existing configuration
• -t, --template — Scaffold full project template (next, vite, react-router, astro, laravel, tanstack-start)
• --preset — Apply a design system preset (colors, theme, icons, fonts, radius) as a single shareable code
• --base — Choose primitive library: radix (default) or base-ui
• --monorepo — Set up a monorepo structure

WARNING: -y/--yes alone does NOT make init fully non-interactive — it still prompts for component library selection. Always use -d to skip ALL prompts.

Deprecated in CLI v4: --style, --base-color, --src-dir, --no-base-style, and --css-variables flags are removed and will error. The registry:build and registry:mcp registry types are also deprecated. Use registry:base and registry:font instead.

The init command:

1. Detects your framework (Next.js, Vite, React Router, Astro, Laravel, TanStack Start)
2. Installs required dependencies (Radix UI, tailwind-merge, class-variance-authority)
3. Creates components.json configuration
4. Sets up the cn() utility function
5. Configures CSS variables for theming

Add Components

# Add specific components
npx shadcn@latest add button dialog card

# Add all available components
npx shadcn@latest add --all

# Add from a custom registry
npx shadcn@latest add @v0/dashboard
npx shadcn@latest add @acme/custom-button

# Add from AI Elements registry
npx shadcn@latest add https://elements.ai-sdk.dev/api/registry/all.json

Options:

• -o, --overwrite — Overwrite existing files
• -p, --path — Custom install path
• -a, --all — Install all components
• --dry-run — Preview what will be added without writing files
• --diff — Show diff of changes when updating existing components
• --view — Display a registry item's source code inline

Search & List

npx shadcn@latest search button
npx shadcn@latest list @v0

Build (Custom Registry)

npx shadcn@latest build
npx shadcn@latest build ./registry.json -o ./public/r

View, Info & Docs (CLI v4)

# View a registry item's source before installing
npx shadcn@latest view button

# Show project diagnostics — config, installed components, dependencies
npx shadcn@latest info

# Get docs, code, and examples for any component (agent-friendly output)
npx shadcn@latest docs button
npx shadcn@latest docs dialog

shadcn docs gives coding agents the context to use primitives correctly — returns code examples, API reference, and usage patterns inline.

Migrate

npx shadcn@latest migrate rtl    # RTL support migration
npx shadcn@latest migrate radix  # Migrate to unified radix-ui package
npx shadcn@latest migrate icons  # Icon library changes

# Migrate components outside the default ui directory
npx shadcn@latest migrate radix src/components/custom

shadcn/skills (CLI v4)

shadcn/skills gives coding agents the context they need to work with components and registries correctly. It covers both Radix and Base UI primitives, updated APIs, component patterns, and registry workflows. The skill knows how to use the CLI, when to invoke it, and which flags to pass — so agents produce code that matches your design system.

Install: pnpm dlx skills add shadcn/ui

Unified Radix UI Package (February 2026)

The new-york style now uses a single radix-ui package instead of individual @radix-ui/react-* packages:

// OLD — individual packages
import * as DialogPrimitive from "@radix-ui/react-dialog"

// NEW — unified package
import { Dialog as DialogPrimitive } from "radix-ui"

To migrate existing projects: npx shadcn@latest migrate radix. After migration, remove unused @radix-ui/react-* packages from package.json.

Base UI Support (January 2026)

shadcn/ui now supports Base UI as an alternative to Radix UI for the underlying primitive library. Components look and behave the same way regardless of which library you choose — only the underlying implementation changes.

Choose during init: npx shadcn@latest init --base base-ui

The CLI pulls the correct component variant based on your project configuration automatically.

Configuration (components.json)

The components.json file configures how shadcn/ui works in your project:

{
  "$schema": "https://ui.shadcn.com/schema.json",
  "style": "new-york",
  "rsc": true,
  "tsx": true,
  "tailwind": {
    "config": "tailwind.config.ts",
    "css": "src/app/globals.css",
    "baseColor": "zinc",  // Options: gray, neutral, slate, stone, zinc, mauve, olive, mist, taupe
    "cssVariables": true
  },
  "aliases": {
    "components": "@/components",
    "utils": "@/lib/utils",
    "ui": "@/components/ui",
    "lib": "@/lib",
    "hooks": "@/hooks"
  },
  "registries": {
    "v0": {
      "url": "https://v0.dev/chat/api/registry"
    },
    "ai-elements": {
      "url": "https://elements.ai-sdk.dev/api/registry"
    }
  }
}

Namespaced Registries

Configure multiple registries for your project:

{
  "registries": {
    "acme": {
      "url": "https://acme.com/registry/{name}.json"
    },
    "private": {
      "url": "https://internal.company.com/registry/{name}.json",
      "headers": {
        "Authorization": "Bearer ${REGISTRY_TOKEN}"
      }
    }
  }
}

Install using namespace syntax:

npx shadcn@latest add @acme/header @private/auth-form

Theming

CSS Variables

shadcn/ui uses CSS custom properties for theming, defined in globals.css:

@theme inline {
  --color-background: oklch(0.145 0 0);
  --color-foreground: oklch(0.985 0 0);
  --color-card: oklch(0.205 0 0);
  --color-card-foreground: oklch(0.985 0 0);
  --color-primary: oklch(0.488 0.243 264.376);
  --color-primary-foreground: oklch(0.985 0 0);
  --color-secondary: oklch(0.269 0 0);
  --color-secondary-foreground: oklch(0.985 0 0);
  --color-muted: oklch(0.269 0 0);
  --color-muted-foreground: oklch(0.708 0 0);
  --color-accent: oklch(0.269 0 0);
  --color-accent-foreground: oklch(0.985 0 0);
  --color-destructive: oklch(0.396 0.141 25.723);
  --color-border: oklch(0.269 0 0);
  --color-input: oklch(0.269 0 0);
  --color-ring: oklch(0.488 0.243 264.376);
  --radius: 0.625rem;
  /* CLI v4: radius tokens use multiplicative calc instead of additive */
  --radius-xs: calc(var(--radius) * 0.5);
  --radius-sm: calc(var(--radius) * 0.75);
  --radius-md: calc(var(--radius) * 0.875);
  --radius-lg: var(--radius);
  --radius-xl: calc(var(--radius) * 1.5);
}

Dark Mode

For dark mode, use the dark class on <html>:

// app/layout.tsx
<html lang="en" className="dark">

Or use next-themes for toggling:

import { ThemeProvider } from 'next-themes'

<ThemeProvider attribute="class" defaultTheme="dark">
  {children}
</ThemeProvider>

Custom Colors

Add application-specific colors alongside shadcn defaults:

@theme inline {
  /* shadcn defaults above... */

  /* Custom app colors */
  --color-priority-urgent: oklch(0.637 0.237 15.163);
  --color-priority-high: oklch(0.705 0.213 47.604);
  --color-status-done: oklch(0.723 0.219 149.579);
}

Use in components:

<span className="text-[var(--color-priority-urgent)]">Urgent</span>
// Or with Tailwind v4 theme():
<span className="text-priority-urgent">Urgent</span>

Most Common Components

Component	Use Case
button	Actions, form submission
card	Content containers
dialog	Modals, confirmation prompts
input / textarea	Form fields
select	Dropdowns
table	Data display
tabs	View switching
command	Command palette (Cmd+K)
dropdown-menu	Context menus
popover	Floating content
tooltip	Hover hints
badge	Status indicators
avatar	User profile images
scroll-area	Scrollable containers
separator	Visual dividers
label	Form labels
sheet	Slide-out panels
skeleton	Loading placeholders

Design Direction for shadcn on Vercel

shadcn/ui is not only a component source generator. In the Vercel stack it is the default interface language. Do not stop at "the component works." Compose pages that feel deliberate, high-signal, and consistent.

Default aesthetic for product UI

• Prefer style: new-york for product, dashboard, AI, and admin surfaces.
• Default to dark mode for dashboards, AI apps, internal tools, settings, and developer-facing products. Use light mode only when the product is clearly content-first or editorial.
• Use Geist Sans for interface text and Geist Mono for code, metrics, IDs, timestamps, commands.
• Prefer zinc, neutral, or slate as the base palette. Use one accent color through --color-primary.
• Build core surfaces from tokens: bg-background, bg-card, text-foreground, text-muted-foreground, border-border, ring-ring. Avoid ad-hoc hex values.
• Keep radius consistent. The default --radius: 0.625rem is a strong baseline.
• Use one density system per page: comfortable (gap-6 / p-6 / text-sm) or compact (gap-4 / p-4 / text-sm).
• Keep icons quiet and consistent. Lucide icons at h-4 w-4 or h-5 w-5.

Reach for this first

Use case	Reach for this first	Why
Settings page	Tabs + Card + Form	Clear information grouping with predictable save flows
Data dashboard	Card + Badge + Table + DropdownMenu	Covers summary, status, dense data, and row actions without custom shells
CRUD table	Table + DropdownMenu + Sheet + AlertDialog	Supports browse, act, edit, and destructive confirmation in a standard pattern
Auth screen	Card + Label + Input + Button + Alert	Keeps entry flows focused and gives errors a proper treatment
Global search	Command + Dialog	Fast keyboard-first discovery with an established interaction model
Mobile nav	Sheet + Button + Separator	Provides a compact navigation shell that adapts cleanly to small screens
Detail page	header + Badge + Separator + Card	Balances hierarchy, metadata, and supporting content without over-nesting
Filters	Card sidebar + Sheet + Select	Works for persistent desktop filters and collapsible mobile controls
Empty/loading/error states	Card + Skeleton + Alert	Gives non-happy paths a designed surface instead of placeholder text

Composition recipes

• Settings page: Tabs + Card per group + Separator + save action
• Admin dashboard: summary Cards + filter bar + Table
• Entity detail: header + status Badge + main Card + side Card + AlertDialog for destructive
• Search-heavy: Command for quick find, Popover for pickers, Sheet for mobile filters
• Auth/onboarding: centered Card + social Separator + inline Alert for errors
• Destructive flows: AlertDialog (not Dialog) for confirmation

Anti-patterns to avoid

• Raw button / input / select / div when shadcn primitives exist
• Repeated div rounded-xl border p-6 instead of Tabs / Table / Sheet / Dialog
• Multiple accent colors fighting each other
• Nested cards inside cards inside cards
• Large gradient backgrounds and glassmorphism on every surface
• Mixing arbitrary spacing and radius values
• Using Dialog for destructive confirmation instead of AlertDialog
• Shipping empty/loading/error states without design treatment
• Using ad-hoc Tailwind palette classes for foundational surfaces instead of theme tokens

Building a Custom Registry

Create your own component registry to share across projects:

Registry Types (CLI v4)

Type	Purpose
registry:ui	Individual UI components
registry:base	Full design system payload — components, deps, CSS vars, fonts, config
registry:font	Font configuration as a first-class registry item

1. Define registry.json

[
  {
    "name": "my-component",
    "type": "registry:ui",
    "title": "My Component",
    "description": "A custom component",
    "files": [
      {
        "path": "components/my-component.tsx",
        "type": "registry:ui"
      }
    ],
    "dependencies": ["lucide-react"]
  }
]

2. Build

npx shadcn@latest build
# Outputs to public/r/my-component.json

3. Consume

npx shadcn@latest add https://your-domain.com/r/my-component.json

Component Gotchas

shadcn init Breaks Geist Font in Next.js (Tailwind v4)

shadcn init rewrites globals.css and may introduce --font-sans: var(--font-sans) — a circular self-reference that breaks font loading. Tailwind v4's @theme inline resolves CSS custom properties at parse time, not runtime — so even var(--font-geist-sans) won't work because Next.js injects that variable via className at runtime.

The fix: Use literal font family names in @theme inline:

/* In @theme inline — CORRECT (literal names) */
--font-sans: "Geist", "Geist Fallback", ui-sans-serif, system-ui, sans-serif;
--font-mono: "Geist Mono", "Geist Mono Fallback", ui-monospace, monospace;

/* WRONG — circular, resolves to nothing */
--font-sans: var(--font-sans);

/* ALSO WRONG — @theme inline can't resolve runtime CSS variables */
--font-sans: var(--font-geist-sans);

After running shadcn init, always:

1. Replace font declarations in @theme inline with literal Geist font names (as shown above)
2. Move the font variable classNames from <body> to <html> in layout.tsx:

// layout.tsx — font variables on <html>, not <body>
<html lang="en" className={`${geistSans.variable} ${geistMono.variable}`}>
  <body className="antialiased">

Avatar Has No size Prop

The shadcn Avatar component does not accept a size variant prop. Control size with Tailwind classes:

// WRONG — no size variant exists
<Avatar size="lg" />  // ❌ TypeScript error / silently ignored

// CORRECT — use Tailwind
<Avatar className="h-12 w-12">
  <AvatarImage src={user.image} />
  <AvatarFallback>JD</AvatarFallback>
</Avatar>

// Small avatar
<Avatar className="h-6 w-6"> ... </Avatar>

This applies to most shadcn components — they use Tailwind classes for sizing, not variant props. If you need reusable size variants, add them yourself via cva in the component source.

Common Patterns

cn() Utility

All shadcn components use the cn() utility for conditional class merging:

import { clsx, type ClassValue } from 'clsx'
import { twMerge } from 'tailwind-merge'

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}

Extending Components

Since you own the source code, extend components directly:

// components/ui/button.tsx — add your custom variant
const buttonVariants = cva('...', {
  variants: {
    variant: {
      default: '...',
      destructive: '...',
      // Add custom variants
      success: 'bg-green-600 text-white hover:bg-green-700',
      premium: 'bg-gradient-to-r from-purple-500 to-pink-500 text-white',
    },
  },
})

Wrapping with TooltipProvider

Many components require TooltipProvider at the root:

// app/layout.tsx
import { TooltipProvider } from '@/components/ui/tooltip'

export default function RootLayout({ children }) {
  return (
    <html lang="en" className="dark">
      <body>
        <TooltipProvider>{children}</TooltipProvider>
      </body>
    </html>
  )
}

Framework Support

• Next.js — Full support (App Router + Pages Router)
• Vite — Full support
• React Router — Full support
• Astro — Full support
• Laravel — Full support (via Inertia)
• TanStack Start — Full support

Presets (CLI v4)

Presets bundle your entire design system config (colors, theme, icon library, fonts, radius) into a single shareable code. One string configures everything:

# Apply a preset during init
npx shadcn@latest init --preset <code>

# Switch presets in an existing project (reconfigures everything including components)
npx shadcn@latest init --preset <code>

Build custom presets on shadcn/create — preview how colors, fonts, and radius apply to real components before publishing.

RTL Support (2026)

The CLI handles RTL transformation at install time:

npx shadcn@latest migrate rtl

Converts directional classes (ml-4, left-2) to logical properties (ms-4, start-2) automatically.

Official Documentation

• shadcn/ui
• Components
• CLI
• Theming
• Custom Registry
• Registry Directory
• GitHub: shadcn/ui