shadcn · SHAD0006

Use known design-system classes

Avoid classes that are not declared by the project's Tailwind theme.

SHAD0006vite-doctor/shadcnuiwarnSuggestion

shadcn/no-unknown-classessrc/rule-packs/shadcn/rules/index.ts Upstream docs

Run this rule

pnpm vite-doctor . --extends shadcn/strict --rules shadcn/no-unknown-classes

Misspelled or unsupported class names generate no CSS. Without a resolvable Tailwind theme, the Rule uses a reduced fallback that includes bundled utility names plus discovered @utility names and CSS class selectors, as in the example below. That fallback cannot validate theme tokens or provide spelling suggestions.

Recommended fix

Correct the class name or declare the intended utility in the theme. Allow external stylesheet classes by exact name only when the application loads their CSS.

Useful links

Rule reference

Example

Correct a utility name using the fallback grammar

Before

<div className="flex-cols" />

After