acaprino/shadcn-ui

shadcn/ui Expert

Guidance for building production UIs with shadcn/ui. Covers component composition, advanced patterns, registry authoring, theming, and integration with the broader frontend ecosystem.

Docs: https://ui.shadcn.com/docs

Core Philosophy

shadcn/ui is NOT a component library -- it is a collection of beautifully designed, accessible components you copy into your project and own. Five pillars:

1. Open Code - components live in your codebase, fully editable
2. Composition - small primitives combine into complex UI
3. Distribution - registry system for sharing component sets
4. Beautiful Defaults - production-ready out of the box
5. AI-Ready - data-slot attributes and structured props for LLM tooling

When This Skill Activates

• Adding shadcn/ui to a project (npx shadcn@latest init)
• Installing or customizing individual components (npx shadcn@latest add)
• Building complex patterns: data tables, forms with validation, sidebar navigation
• Theming, color system customization, dark mode
• Creating or consuming a custom registry
• Migrating from Tailwind v3 to v4 with shadcn

Synergy with Other Frontend Skills

This skill works alongside the other frontend skills. Route to them when appropriate:

| Need | Route to | |------|----------| | CSS architecture, modern CSS features, responsive patterns | frontend-design | | Page layout composition, grid systems, breakpoint strategy | frontend-layout agent | | Animations, micro-interactions, visual polish | frontend-design agent | | UX flows, design tokens, component hierarchy | frontend-design agent | | Distinctive visual identity, avoiding generic AI aesthetics | frontend-css skill | | React 19 patterns, Server Components, performance | react-performance-optimizer agent |

This skill handles shadcn-specific concerns: which components to use, how to compose them, registry patterns, form/table/sidebar architecture, and shadcn theming.

Live Component Lookup

This skill contains reference patterns for the most complex components (Data Table, Form, Sidebar, Dialog). For any other component's API, props, or usage -- spawn a quick-searcher agent to fetch the docs in real time.

URL patterns

All component docs follow a predictable URL scheme:

| Resource | URL pattern | |----------|-------------| | Component docs | https://ui.shadcn.com/docs/components/{name} | | Form integrations | https://ui.shadcn.com/docs/forms/{library} | | Blocks | https://ui.shadcn.com/blocks | | Registry | https://ui.shadcn.com/docs/registry | | Themes | https://ui.shadcn.com/themes | | CLI reference | https://ui.shadcn.com/docs/cli | | Tailwind v4 | https://ui.shadcn.com/docs/tailwind-v4 | | Changelog | https://ui.shadcn.com/docs/changelog |

How to look up a component

When you need API details for a specific component (e.g., Combobox, Toast, Sheet):

1. Spawn a research:quick-searcher agent with this prompt template:

   Fetch https://ui.shadcn.com/docs/components/{component-name} and extract:
   - Sub-components and their props
   - Required accessibility attributes
   - Install command
   - Key usage patterns and code examples
   Return structured findings.
   

2. For Radix primitive API details (inherited by shadcn), fetch: https://www.radix-ui.com/primitives/docs/components/{component-name}

3. For TanStack Table API (used by Data Table), fetch: https://tanstack.com/table/latest/docs/introduction

Component catalog (by category)

For quick reference when choosing components:

| Category | Components | |----------|------------| | Layout | Sidebar, Resizable, Collapsible, Separator, Aspect Ratio | | Overlay | Dialog, Sheet, Drawer, Alert Dialog, Popover, Tooltip, Hover Card | | Form | Input, Textarea, Select, Checkbox, Radio Group, Switch, Slider, Toggle, Toggle Group, Date Picker, Combobox | | Data Display | Table, Data Table, Card, Badge, Avatar, Calendar | | Feedback | Alert, Toast (Sonner), Progress, Skeleton | | Navigation | Navigation Menu, Breadcrumb, Pagination, Tabs, Command, Menubar, Dropdown Menu, Context Menu | | Typography | Label, Separator |

Installation and Setup

New project

npx shadcn@latest init
# Choose: New York style (default, "default" style is deprecated)
# Choose: Tailwind v4 + React 19 (current default)

Add components

npx shadcn@latest add button dialog form sidebar data-table
# Or add a block:
npx shadcn@latest add dashboard-01

CLI v4 features (March 2026+)

shadcn add --dry-run dialog    # preview changes without writing
shadcn add --diff dialog       # show diff of what would change
shadcn info                    # show installed components, framework, CSS vars
shadcn docs dialog             # fetch component docs from CLI
shadcn init --template next    # scaffold with framework template

Component Composition

shadcn components are composable primitives. Build complex UI by nesting them.

Pattern: Sub-component composition

<Dialog>
  <DialogTrigger asChild>
    <Button variant="outline">Edit Profile</Button>
  </DialogTrigger>
  <DialogContent>
    <DialogHeader>
      <DialogTitle>Edit Profile</DialogTitle>
      <DialogDescription>Update your information.</DialogDescription>
    </DialogHeader>
    {/* your content */}
  </DialogContent>
</Dialog>

Pattern: Slot/asChild delegation

Use asChild to delegate rendering to a child element -- avoids extra DOM nodes and lets you use router Links, custom buttons, etc.

<DialogTrigger asChild>
  <Link href="/settings">Open Settings</Link>
</DialogTrigger>

Pattern: cn() utility for conditional classes

import { cn } from "@/lib/utils"

<div className={cn(
  "rounded-lg border p-4",
  isActive && "border-primary bg-primary/5",
  className
)} />

Pattern: CVA variants for custom components

import { cva, type VariantProps } from "class-variance-authority"

const badgeVariants = cva("inline-flex items-center rounded-full px-2.5 py-0.5 text-xs", {
  variants: {
    variant: {
      default: "bg-primary text-primary-foreground",
      destructive: "bg-destructive text-destructive-foreground",
      outline: "border text-foreground",
    },
  },
  defaultVariants: { variant: "default" },
})

Key Patterns

Data Table

3-file architecture with TanStack Table. See references/advanced-patterns.md for full column definition, sorting, filtering, pagination, and row selection patterns.

• columns.tsx - column definitions (ColumnDef<TData>[])
• data-table.tsx - table wrapper with useReactTable
• page.tsx - server component for data fetching

Form + Zod Validation

React Hook Form + Zod resolver. See references/advanced-patterns.md for field patterns, dynamic arrays, and validation modes.

const form = useForm<z.infer<typeof schema>>({
  resolver: zodResolver(schema),
  defaultValues: { title: "" }
})

Sidebar Navigation

Provider-based with SidebarProvider. Supports collapsible="icon" and collapsible="offcanvas". See references/advanced-patterns.md for nested navigation, mobile responsive, and useSidebar() hook.

Theming

Color system (Tailwind v4 / OKLCH)

New projects use OKLCH for perceptual color uniformity. Colors defined as CSS variables in globals.css:

@theme inline {
  --color-background: var(--background);
  --color-foreground: var(--foreground);
  --color-primary: var(--primary);
  --color-primary-foreground: var(--primary-foreground);
  /* ... */
}

Dark mode

Toggle via class on <html>. All shadcn components respect dark: variants automatically.

Customization approach

1. Edit CSS variables in globals.css for global theme changes
2. Use cn() for per-instance overrides
3. Edit the component source directly for structural changes (you own the code)
4. Use data-slot attributes for targeted CSS overrides without class specificity fights

Tailwind v4 Migration

See references/migration-guide.md for the step-by-step migration from Tailwind v3 to v4, including:

• npx @tailwindcss/upgrade@next codemod
• Animation library swap (tailwindcss-animate to tw-animate-css)
• CSS variable restructuring with @theme inline
• forwardRef removal for React 19
• data-slot adoption

Registry System

Build and distribute your own component sets. See references/registry-guide.md for:

• registry.json schema and item types
• Directory structure conventions
• Build and publish workflow
• registry:base for full design systems

Common Pitfalls

See references/pitfalls.md for detailed problems and fixes:

• Tailwind class collisions with custom config
• SSR hydration errors (Accordion, etc.)
• Bundle bloat from wildcard imports
• No auto-updates -- manual shadcn add to refresh components
• forwardRef breakage in React 19
• Accessibility regressions from missing ARIA attributes

Community Resources

• Blocks: https://ui.shadcn.com/blocks -- official composable page sections
• shadcnblocks.com -- 1100+ community blocks and templates
• registry.directory -- third-party registry explorer
• shadcn-admin (GitHub, 6k+ stars) -- full admin dashboard starter
• next-forge (GitHub, 6.9k+ stars) -- Turborepo monorepo with payments, analytics, i18n

Server vs Client Components

• Data-fetching pages: Server Components (default in Next.js App Router)
• Interactive components (Dialog, Form, DataTable): "use client"
• Column definitions: "use client" (they reference React components)
• Prefer Server Components for layout shells, route segments
• Use "use client" boundary as low in the tree as possible