Rules — overview

Plumb’s rules are the catalog of design-system checks the engine runs against each page snapshot. Every rule has:

• A stable id, slash-separated (<category>/<id>).
• A default severity (info, warning, error).
• A docs page — the one you get from plumb explain <id>.

Built-in rules

• a11y/touch-target — flags interactive elements smaller than a11y.touch_target.
• baseline/rhythm — flags text whose typographic baselines miss the configured vertical-rhythm grid.
• color/contrast-aa — flags text whose foreground/background contrast misses WCAG 2.1 AA.
• color/palette-conformance — flags element colors that aren’t members of the configured palette.
• edge/near-alignment — flags element edges that almost-but-not-quite line up with sibling edges.
• opacity/scale-conformance — flags opacity values that aren’t members of opacity.scale.
• radius/scale-conformance — flags border-radius values that aren’t members of radius.scale.
• shadow/scale-conformance — flags box-shadow values that aren’t in shadow.scale.
• sibling/height-consistency — flags sibling elements in the same visual row whose heights drift from the row’s median.
• sibling/padding-consistency — flags sibling elements whose padding drifts from the group median.
• spacing/grid-conformance — flags spacing values that aren’t multiples of spacing.base_unit.
• spacing/scale-conformance — flags spacing values that aren’t members of spacing.scale.
• type/family-conformance — flags font-family values that aren’t in type.families.
• type/scale-conformance — flags font-size values that aren’t members of type.scale.
• type/weight-conformance — flags font-weight values that aren’t in type.weights.
• z/scale-conformance — flags z-index values that aren’t in z_index.scale.