Alert

Visible feedback with explicit none, polite, or assertive announcement policy.

When to use it. Use it for authored feedback whose announcement urgency is selected deliberately.

Native baseline Exact fallback

Alert primary example

Static guidance

Visible without a live-region announcement.

Session expired

<.alert announcement={:polite} title="Draft saved" description="Your changes are available." />

<.alert> The caller's native elements, names, and document relationships remain authoritative.
package CSS Package CSS applies scoped shadcn-style tokens, layout, focus, and state presentation without changing the native contract.
gallery only Theme switching, source copying, search, fixtures, and inspection controls on this page belong to the gallery only; :alert does not ship them.
application boundary ShadcnUI does not add application state, authorization, persistence, transport events, or a JavaScript behavior layer to this component.

Examples use package semantic tokens in explicit light and dark scopes.

Destructive color does not infer urgency; announcement policy determines role and live state.

Alert support and fallback
Feature	Locked-engine evidence	When missing
Native baseline	Reviewed in the locked Chromium, Firefox, and WebKit evidence matrix.	Title, description, and native actions remain available without JavaScript.
Exact fallback	The locked-engine matrix retains the documented native or static outcome.	Title, description, and native actions remain available without JavaScript.

The application owns insertion, dismissal, retry, lifecycle, and action outcomes.

Catalogue identity foundation.alert, adapted from unscripted/ui commit bd8f403030c8d1f46804da6eda733fde7e908e63 under its MIT notice.

The documentation presentation is adapted locally; ShadcnUI's Phoenix API and native semantic contract remain authoritative.

Adapt native alert markup into a stateless HEEX API with explicit announcement semantics and caller-owned lifecycle.