diff --git a/.storybook/main.ts b/.storybook/main.ts
index a62960db85..865ae90848 100644
--- a/.storybook/main.ts
+++ b/.storybook/main.ts
@@ -13,7 +13,7 @@ const isChromatic = process.env.STORYBOOK_STORY_SET === 'chromatic';
 
 // All stories for full development
 const allStories = isChromatic
-  ? ['packages/ui']
+  ? ['packages/ui', 'plugins/app']
   : [
       'packages/ui',
       'packages/core-components',
diff --git a/.storybook/preview.tsx b/.storybook/preview.tsx
index 022b6123e2..916c48951d 100644
--- a/.storybook/preview.tsx
+++ b/.storybook/preview.tsx
@@ -6,7 +6,7 @@ import { definePreview } from '@storybook/react-vite';
 import React, { useEffect } from 'react';
 import { TestApiProvider } from '@backstage/test-utils';
 import { AlertDisplay } from '@backstage/core-components';
-import { apis } from './support/apis';
+import { apis, appThemeApi } from './support/apis';
 import { useGlobals } from 'storybook/preview-api';
 import { UnifiedThemeProvider, themes } from '@backstage/theme';
 import { allModes } from './modes';
@@ -157,6 +157,10 @@ export default definePreview({
         };
       }, [selectedTheme, selectedThemeName]);
 
+      useEffect(() => {
+        appThemeApi.setActiveThemeId(selectedThemeMode);
+      }, [selectedThemeMode]);
+
       document.body.style.backgroundColor = 'var(--bui-bg-app)';
       document.body.style.padding =
         isFullscreen && selectedBackground !== 'app' ? '1rem' : '';
diff --git a/.storybook/support/apis.js b/.storybook/support/apis.js
index 905c5f2dc8..42085591c0 100644
--- a/.storybook/support/apis.js
+++ b/.storybook/support/apis.js
@@ -1,5 +1,6 @@
 import {
   AlertApiForwarder,
+  AppThemeSelector,
   ErrorAlerter,
   ErrorApiForwarder,
   GithubAuth,
@@ -13,6 +14,7 @@ import {
 
 import {
   alertApiRef,
+  appThemeApiRef,
   errorApiRef,
   githubAuthApiRef,
   gitlabAuthApiRef,
@@ -24,10 +26,16 @@ import {
   featureFlagsApiRef,
 } from '@backstage/core-plugin-api';
 
+import { themes } from '@backstage/theme';
+
 import { translationApiRef } from '@backstage/core-plugin-api/alpha';
 import { MockTranslationApi } from '@backstage/test-utils/alpha';
 
 const configApi = new ConfigReader({});
+export const appThemeApi = AppThemeSelector.createWithStorage([
+  { id: 'light', title: 'Light', variant: 'light', theme: themes.light },
+  { id: 'dark', title: 'Dark', variant: 'dark', theme: themes.dark },
+]);
 const featureFlagsApi = new LocalStorageFeatureFlags();
 const alertApi = new AlertApiForwarder();
 const errorApi = new ErrorAlerter(alertApi, new ErrorApiForwarder());
@@ -62,6 +70,7 @@ const translationApi = MockTranslationApi.create();
 
 export const apis = [
   [configApiRef, configApi],
+  [appThemeApiRef, appThemeApi],
   [featureFlagsApiRef, featureFlagsApi],
   [alertApiRef, alertApi],
   [errorApiRef, errorApi],
diff --git a/plugins/app/src/components/Toast/Toast.stories.tsx b/plugins/app/src/components/Toast/Toast.stories.tsx
index f008bc2550..10eb05476d 100644
--- a/plugins/app/src/components/Toast/Toast.stories.tsx
+++ b/plugins/app/src/components/Toast/Toast.stories.tsx
@@ -28,7 +28,7 @@ const toastQueue = new ToastQueue<ToastApiMessageContent>({
 });
 
 const meta = preview.meta({
-  title: 'Plugins/App/Toast',
+  title: 'App/Toast',
   component: ToastContainer,
   parameters: {
     layout: 'centered',
@@ -157,6 +157,35 @@ export const Default = meta.story({
   ),
 });
 
+const previewQueue = new ToastQueue<ToastApiMessageContent>({
+  maxVisibleToasts: 4,
+});
+previewQueue.add({
+  title: 'Changes saved successfully',
+  description: 'Your changes have been saved.',
+  status: 'success',
+});
+
+export const PreviewToast = meta.story({
+  render: () => <ToastContainer queue={previewQueue} />,
+});
+
+const timerQueue = new ToastQueue<ToastApiMessageContent>({
+  maxVisibleToasts: 4,
+});
+timerQueue.add(
+  {
+    title: 'Auto-dismissing in 5 seconds',
+    description: 'This toast will disappear automatically.',
+    status: 'info',
+  },
+  { timeout: 5000 },
+);
+
+export const PreviewToastWithTimer = meta.story({
+  render: () => <ToastContainer queue={timerQueue} />,
+});
+
 export const StatusVariants = meta.story({
   render: () => (
     <>
@@ -557,113 +586,4 @@ export const AlertApiIntegration = meta.story({
   },
 });
 
-/**
- * This story tests the real AlertApi integration.
- * It uses the alertApi from the TestApiProvider (set up in storybook preview)
- * and shows how alerts posted via alertApi.post() appear.
- *
- * Note: The storybook preview.tsx renders AlertDisplay from core-components,
- * which still uses Material UI. To test the new ToastDisplay, run the actual
- * Backstage app where the app plugin's elements.tsx is used.
- */
-function RealAlertApiStory() {
-  // eslint-disable-next-line @backstage/no-relative-monorepo-imports
-  const { useApi, alertApiRef } = require('@backstage/core-plugin-api');
-  const alertApi = useApi(alertApiRef);
-
-  return (
-    <Flex direction="column" gap="4">
-      <Flex direction="column" gap="2">
-        <Text variant="body-medium" weight="bold">
-          Real AlertApi Test
-        </Text>
-        <Text variant="body-small">
-          These buttons call alertApi.post() directly. Alerts appear in the OLD
-          AlertDisplay (top of screen) because Storybook uses core-components.
-        </Text>
-        <Text variant="body-small">
-          To test the NEW ToastDisplay, run: yarn start
-        </Text>
-      </Flex>
-      <Flex gap="3">
-        <Button
-          onPress={() =>
-            alertApi.post({
-              message: 'Entity saved successfully!',
-              severity: 'success',
-              display: 'transient',
-            })
-          }
-        >
-          Success (transient)
-        </Button>
-        <Button
-          onPress={() =>
-            alertApi.post({
-              message: 'Catalog refresh in progress',
-              severity: 'info',
-              display: 'transient',
-            })
-          }
-        >
-          Info (transient)
-        </Button>
-        <Button
-          onPress={() =>
-            alertApi.post({
-              message: 'Entity validation has warnings',
-              severity: 'warning',
-              display: 'transient',
-            })
-          }
-        >
-          Warning (transient)
-        </Button>
-        <Button
-          onPress={() =>
-            alertApi.post({
-              message: 'Failed to fetch entity from catalog',
-              severity: 'error',
-              display: 'transient',
-            })
-          }
-        >
-          Error (transient)
-        </Button>
-      </Flex>
-      <Flex gap="3">
-        <Button
-          variant="secondary"
-          onPress={() =>
-            alertApi.post({
-              message: 'This alert stays until dismissed',
-              severity: 'info',
-              display: 'permanent',
-            })
-          }
-        >
-          Permanent Alert
-        </Button>
-        <Button
-          variant="secondary"
-          onPress={() =>
-            alertApi.post({
-              message: 'Critical error - requires attention!',
-              severity: 'error',
-              display: 'permanent',
-            })
-          }
-        >
-          Permanent Error
-        </Button>
-      </Flex>
-    </Flex>
-  );
-}
-
-export const RealAlertApi = meta.story({
-  name: 'Real AlertApi Test',
-  render: () => <RealAlertApiStory />,
-});
-
 export default meta;