Shadcn

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 to get documentation and example URLs for any component.

Principles

1. Use existing components first. Use npx shadcn@latest search to check registries before writing custom UI. Check community registries too.
2. Compose, don't reinvent. Settings page = Tabs + Card + form controls. Dashboard = Sidebar + Card + Chart + Table.
3. Use built-in variants before custom styles. variant="outline", size="sm", etc.
4. 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](./rules/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](./rules/forms.md)

• Forms use FieldGroup + Field. Never use raw div with space-y-* or grid gap-* for form layout.
• InputGroup uses InputGroupInput/InputGroupTextarea. Never raw Input/Textarea inside InputGroup.
• Buttons inside inputs use InputGroup + InputGroupAddon.
• Option sets (2–7 choices) use ToggleGroup. Don't loop Button with manual active state.
• FieldSet + FieldLegend for grouping related checkboxes/radios. Don't use a div with a heading.
• Field validation uses data-invalid + aria-invalid. data-invalid on Field, aria-invalid on the control. For disabled: data-disabled on Field, disabled on the control.

Component Structure → [composition.md](./rules/composition.md)

• Items always inside their Group. SelectItem → SelectGroup. DropdownMenuItem → DropdownMenuGroup. CommandItem → CommandGroup.
• Use asChild (radix) or render (base) for custom triggers. Check base field from npx shadcn@latest info. → [base-vs-radix.md](./rules/base-vs-radix.md)
• Dialog, Sheet, and Drawer always need a Title. DialogTitle, SheetTitle, DrawerTitle required for accessibility. Use className="sr-only" if visually hidden.
• Use full Card composition. CardHeader/CardTitle/CardDescription/CardContent/CardFooter. Don't dump everything in CardContent.
• Button has no isPending/isLoading. Compose with Spinner + data-icon + disabled.
• TabsTrigger must be inside TabsList. Never render triggers directly in Tabs.
• Avatar always needs AvatarFallback. For when the image fails to load.

Use Components, Not Custom Markup → [composition.md](./rules/composition.md)

• Use existing components before custom markup. Check if a component exists before writing a styled div.
• Callouts use Alert. Don't build custom styled divs.
• Empty states use Empty. Don't build custom empty state markup.
• Toast via sonner. Use toast() from sonner.
• Use Separator instead of ` or `.
• Use Skeleton for loading placeholders. No custom animate-pulse divs.
• Use Badge instead of custom styled spans.

Icons → [icons.md](./rules/icons.md)

• Icons in Button use data-icon. data-icon="inline-start" or data-icon="inline-end" on the icon.
• No sizing classes on icons inside components. Components handle icon sizing via CSS. No size-4 or w-4 h-4.
• Pass icons as objects, not string keys. icon={CheckIcon}, not a string lookup.

CLI

• Never decode preset codes or build preset URLs manually. Use npx shadcn@latest preset decode , preset url , or preset open . For project-aware preset detection, use npx shadcn@latest preset resolve.
• Apply preset codes directly with the CLI. Use npx shadcn@latest apply for existing projects, or npx shadcn@latest init --preset when initializing.

Key Patterns

These are the most common patterns that differentiate correct shadcn/ui code. For edge cases, see the linked rule files above.

// Form layout: FieldGroup + Field, not div + Label.

  
    Email
    
  

// Validation: data-invalid on Field, aria-invalid on the control.

  Email
  
  Invalid email.

// Icons in buttons: data-icon, no sizing classes.

  
  Search

// Spacing: gap-*, not space-y-*.
  // correct
           // wrong

// Equal dimensions: size-*, not w-* h-*.
   // correct
 // wrong

// Status colors: Badge variants or semantic tokens, not raw colors.
+20.1%    // correct
+20.1% // wrong

Component Selection

| Need | Use | | -------------------------- | --------------------------------------------------------------------------------------------------- | | Button/action | Button with appropriate variant | | Form inputs | Input, Select, Combobox, Switch, Checkbox, RadioGroup, Textarea, InputOTP, Slider | | Toggle between 2–5 options | ToggleGroup + ToggleGroupItem | | Data display | Table, Card, Badge, Avatar | | Navigation | Sidebar, NavigationMenu, Breadcrumb, Tabs, Pagination | | Overlays | Dialog (modal), Sheet (side panel), Drawer (bottom sheet), AlertDialog (confirmation) | | Feedback | sonner (toast), Alert, Progress, Skeleton, Spinner | | Command palette | Command inside Dialog | | Charts | Chart (wraps Recharts) | | Layout | Card, Separator, Resizable, ScrollArea, Accordion, Collapsible | | Empty states | Empty | | Menus | DropdownMenu, ContextMenu, Menubar | | Tooltips/info | Tooltip, HoverCard, Popover |

Key Fields

The injected project context contains these key fields:

• aliases → use the actual alias prefix for imports (e.g. @/, ~/), never hardcode.
• isRSC → when true, components using useState, useEffect, event handlers, or browser APIs need "use client" at the top of the file. Always reference this field when advising on the directive.
• tailwindVersion → "v4" uses @theme inline blocks; "v3" uses tailwind.config.js.
• tailwindCssFile → the global CSS file where custom CSS variables are defined. Always edit this file, never create a new one.
• style → component visual treatment (e.g. nova, vega).
• base → primitive library (radix or base). Affects component APIs and available props.
• iconLibrary → determines icon imports. Use lucide-react for lucide, @tabler/icons-react for tabler, etc. Never assume lucide-react.
• resolvedPaths → exact file-system destinations for components, utils, hooks, etc.
• framework → routing and file conventions (e.g. Next.js App Router vs Vite SPA).
• packageManager → use this for any non-shadcn dependency installs (e.g. pnpm add date-fns vs npm install date-fns).
• preset → resolved preset code and values for the current project. Use npx shadcn@latest preset resolve --json when you only need preset information.

See [cli.md — info command](./cli.md) for the full field reference.

Component Docs, Examples, and Usage

Run npx shadcn@latest docs to get the URLs for a component's documentation, examples, and API reference. Fetch these URLs to get the actual content.

npx shadcn@latest docs button dialog select

When creating, fixing, debugging, or using a component, always run npx shadcn@latest docs and fetch the URLs first. This ensures you're working with the correct API and usage patterns rather than guessing.

Workflow

1. Get project context — already injected above. Run npx shadcn@latest info again if you need to refresh.
2. Check installed components first — before running add, always check the components list from project context or list the resolvedPaths.ui directory. Don't import components that haven't been added, and don't re-add ones already installed.
3. Find components — npx shadcn@latest search.
4. Get docs and examples — run npx shadcn@latest docs to get URLs, then fetch them. Use npx shadcn@latest view to browse registry items you haven't installed. To preview changes to installed components, use npx shadcn@latest add --diff.
5. Install or update — npx shadcn@latest add. When updating existing components, use --dry-run and --diff to preview changes first (see [Updating Components](#updating-components) below).
6. Fix imports in third-party components — After adding components from community registries (e.g. @bundui, @magicui), check the added non-UI files for hardcoded import paths like @/components/ui/.... These won't match the project's actual aliases. Use npx shadcn@latest info to get the correct ui alias (e.g. @workspace/ui/components) and rewrite the imports accordingly. The CLI rewrites imports for its own UI files, but third-party registry components may use default paths that don't match the project.
7. Review added components — After adding a component or block from any registry, always read the added files and verify they are correct. Check for missing sub-components (e.g. SelectItem without SelectGroup), missing imports, incorrect composition, or violations of the [Critical Rules](#critical-rules). Also replace any icon imports with the project's iconLibrary from the project context (e.g. if the registry item uses lucide-react but the project uses hugeicons, swap the imports and icon names accordingly). Fix all issues before moving on.
8. Registry must be explicit — When the user asks to add a block or component, do not guess the registry. If no registry is specified (e.g. user says "add a login block" without specifying @shadcn, @tailark, etc.), ask which registry to use. Never default to a registry on behalf of the user.
9. Switching presets — Ask the user first: overwrite, partial, merge, or skip?

• Inspect current preset: npx shadcn@latest preset resolve. Use --json when you need structured values.
• Inspect incoming preset: npx shadcn@latest preset decode . Use preset url or preset open to share or open the preset builder.
• Overwrite: npx shadcn@latest apply . Overwrites detected components, fonts, and CSS variables.
• Partial: npx shadcn@latest apply --only theme,font. Updates only the selected preset parts without reinstalling UI components. Supported values are theme and font; comma-separated combinations are allowed. icon is intentionally not supported, because icon changes may require full component reinstall and transforms.
• Merge: npx shadcn@latest init --preset --force --no-reinstall, then run npx shadcn@latest info to list installed components, then for each installed component use --dry-run and --diff to [smart merge](#updating-components) it individually.
• Skip: npx shadcn@latest init --preset --force --no-reinstall. Only updates config and CSS, leaves components as-is.
• Important: Always run preset commands inside the user's project directory. apply only works in an existing project with a components.json file. The CLI automatically preserves the current base (base vs radix) from components.json. If you must use a scratch/temp directory (e.g. for --dry-run comparisons), pass --base explicitly — preset codes do not encode the base.

Updating Components

When the user asks to update a component from upstream while keeping their local changes, use --dry-run and --diff to intelligently merge. NEVER fetch raw files from GitHub manually — always use the CLI.

1. Run npx shadcn@latest add --dry-run to see all files that would be affected.
2. For each file, run npx shadcn@latest add --diff to see what changed upstream vs local.
3. Decide per file based on the diff:

• No local changes → safe to overwrite.
• Has local changes → read the local file, analyze the diff, and apply upstream updates while preserving local modifications.
• User says "just update everything" → use --overwrite, but confirm first.

1. Never use --overwrite without the user's explicit approval.

Quick Reference

# Create a new project.
npx shadcn@latest init --name my-app --preset base-nova
npx shadcn@latest init --name my-app --preset a2r6bw --template vite

# Create a monorepo project.
npx shadcn@latest init --name my-app --preset base-nova --monorepo
npx shadcn@latest init --name my-app --preset base-nova --template next --monorepo

# Initialize existing project.
npx shadcn@latest init --preset base-nova
npx shadcn@latest init --defaults  # shortcut: --template=next --preset=nova (base style implied)

# Apply a preset to an existing project.
npx shadcn@latest apply a2r6bw
npx shadcn@latest apply a2r6bw --only theme
npx shadcn@latest apply a2r6bw --only font
npx shadcn@latest apply a2r6bw --only theme,font

# Inspect preset codes and project preset state.
npx shadcn@latest preset decode a2r6bw
npx shadcn@latest preset url a2r6bw
npx shadcn@latest preset open a2r6bw
npx shadcn@latest preset resolve
npx shadcn@latest preset resolve --json

# Add components.
npx shadcn@latest add button card dialog
npx shadcn@latest add @magicui/shimmer-button
npx shadcn@latest add --all

# Preview changes before adding/updating.
npx shadcn@latest add button --dry-run
npx shadcn@latest add button --diff button.tsx
npx shadcn@latest add @acme/form --view button.tsx

# Search registries.
npx shadcn@latest search @shadcn -q "sidebar"
npx shadcn@latest search @tailark -q "stats"

# Get component docs and example URLs.
npx shadcn@latest docs button dialog select

# View registry item details (for items not yet installed).
npx shadcn@latest view @shadcn/button

Named presets: nova, vega, maia, lyra, mira, luma Templates: next, vite, start, react-router, astro (all support --monorepo) and laravel (not supported for monorepo) Preset codes: Version-prefixed base62 strings (e.g. a2r6bw

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: laguagu
• Source: laguagu/claude-code-nextjs-skills
• License: MIT

Install and usage instructions live in the source repository linked above.