Accessibility builder (`accessibility`) attaching explicit `AccessibilityMetadata` (role, name source, keyboard contract, contrast/navigation data) to override the control's inferred semantics.

Children builder (`child`) attaching a single nested `Control<'msg>` to a container.

Children builder (`children`) attaching an ordered list of nested `Control<'msg>` to a container such as a stack, grid, or panel.

Low-level escape hatch (`create`) building an `Attr<'msg>` from an explicit `name`, `AttrCategory`, and `AttrValue<'msg>`; the foundation the typed builders below wrap.

Builder (`customAttribute`) for a consumer-defined attribute outside the standard set: a free-form `name` carrying an untyped `obj` value, lowered under the `Data` category.

Event builder (`customEvent`) wiring a free-form `eventKind` string to dispatch a fixed `msg`, for events outside the `StandardEventKind` set.

State builder (`enabled`): when `false` the control is disabled (non-interactive, rendered in its `Disabled` visual state); omitted defaults to enabled.

Layout builder (`height`) requesting a fixed control height in device-independent pixels; omitted lets the control size to its content/container.

Data builder (`items`) supplying the ordered string entries of a list-like control as the `Items` attribute.

State builder (`loading`): when `true` the control shows its busy/`Loading` visual state; omitted defaults to not loading.

Layout builder (`margin`) setting uniform outer spacing in pixels around the control within its parent; omitted defaults to no margin.

Event builder (`on`) subscribing to an event by `eventKind` string and dispatching a fixed `msg` when it fires, ignoring the event payload.

Event builder (`onWith`) subscribing to an event by `eventKind` string and computing the dispatched message from the `ControlEvent` via `map`, giving access to the payload.

Layout builder (`padding`) setting uniform inner spacing in pixels between the control's edge and its content; omitted defaults to no padding.

State builder (`readOnly`): when `true` an input control such as a text-box displays its value but rejects edits; omitted defaults to editable.

State builder (`selected`): when `true` marks the control as selected (e.g. a toggle, radio, or list item in its `Selected` visual state); omitted defaults to unselected.

Schema-checked builder (`standardAttribute`) producing an `Attr<'msg>` from a typed `StandardAttributeName` and `StandardAttributeValue<'msg>`, keeping the attribute within the recognised contract surface.

Event builder (`standardEvent`) wiring a typed `StandardEventKind` to dispatch a fixed `msg` when that built-in event fires on the control.

Style builder (`style`) attaching a single named style class by string — the free-form counterpart to the typed `styleClasses` builder.

Feature 093 (E3): attach an ordered list of style classes (list order = attach order). Lowers to a single `Style`-category attribute carrying `StyleClassesValue`. Absent ≡ `[]` ≡ the behaviour-preserving base case (FR-005). The last `styleClasses` attribute on a control wins (the codebase's last-writer attribute convention).

Content builder (`text`) setting the control's display text — the label of a button or text-block, or the caption shown by content-bearing kinds.

Theme builder (`theme`) attaching a `Theme` palette/metrics to the control subtree, overriding the inherited theme for it and its descendants.

Validation builder (`validation`) attaching a `ValidationState` (`Valid`/`Invalid`/`Pending`) to an input control, surfacing its validity in the resolved visual state.

Content builder (`value`) setting the current value of an input control such as a text-box, carried as the `Value` attribute.

State builder (`visible`): when `false` the control is hidden from layout and paint; omitted defaults to visible.

Feature 093 (E3): set the control's current `VisualState` for the resolver. A host wires its `ControlRuntime` Hover/Press/Focus state into this each frame; it rides the control through the keyed reconciler so a state-driven look survives a sibling shift (FR-006, SC-005). Absent ≡ `Normal` ≡ the behaviour-preserving base case.

Layout builder (`width`) requesting a fixed control width in device-independent pixels; omitted lets the control size to its content/container.