Module rules 

Rule engine — the Rule trait and the built-in registry.

To add a new rule, see .agents/rules/rule-engine-patterns.md. The short version:

1. Add a module under src/rules/ with a type implementing Rule.
2. Register it in register_builtin.
3. Add a golden snapshot test under tests/.
4. Document it at docs/src/rules/<rule-id>.md.

Modules

a11y

Accessibility rules.

baseline

Baseline-rhythm rules.

color

Color rules.

edge

Edge-alignment rules.

opacity

Opacity rules.

radius

Border-radius rules.

shadow

Box-shadow rules.

sibling

Sibling-relationship rules.

spacing

Spacing rules.

type_

Type-scale rules.

z

Z-index rules.

Structs

RuleMetadata

Static metadata needed by output formats and rule listings.

Traits

Rule

A rule — the fundamental unit of work in the engine.

Functions

builtin_rule_metadata

Return metadata for every built-in rule, sorted by rule id.

register_builtin

Return every built-in rule in registration order. Registration order is not part of the public contract — the engine sorts the resulting violations by (rule_id, viewport, selector, dom_order) before return.