Core: Add experimentalReview feature flag and make the features type augmentable

code/.storybook/main.ts

@@ -162,6 +162,7 @@ const config = defineMain({
     experimentalDocgenServer: process.env.STORYBOOK_EXPERIMENTAL_DOCGEN_SERVER === 'true',
     experimentalReactComponentMeta: true,
     changeDetection: true,
+    experimentalReview: true,
   },
   staticDirs: [{ from: './bench/bundle-analyzer', to: '/bundle-analyzer' }],
   viteFinal: async (viteConfig: InlineConfig, { configType }: Options) => {

code/core/src/core-server/presets/common-preset.ts

@@ -45,6 +45,7 @@ import { initCreateNewStoryChannel } from '../server-channel/create-new-story-ch
 import { initFileSearchChannel } from '../server-channel/file-search-channel.ts';
 import { initGhostStoriesChannel } from '../server-channel/ghost-stories-channel.ts';
 import { initOpenInEditorChannel } from '../server-channel/open-in-editor-channel.ts';
+import { isReviewFeatureEnabled } from '../../shared/review/features.ts';
 import { initReviewChannel } from '../server-channel/review-channel.ts';
 import { initTelemetryChannel } from '../server-channel/telemetry-channel.ts';
 import { initializeChecklist } from '../utils/checklist.ts';
@@ -230,6 +231,7 @@ export const features: PresetProperty<'features'> = async (existing) => ({
   componentsManifest: false,
   controls: true,
   disallowImplicitActionsInRenderV8: true,
+  experimentalReview: false,
   highlight: true,
   interactions: true,
   legacyDecoratorFileOrder: false,
@@ -300,7 +302,9 @@ export const experimental_serverChannel = async (
   initCreateNewStoryChannel(channel, options);
   initGhostStoriesChannel(channel, options);
   initOpenInEditorChannel(channel);
-  initReviewChannel(channel);
+  if (isReviewFeatureEnabled(await options.presets.apply('features'))) {
+    initReviewChannel(channel);
+  }
   initTelemetryChannel(channel);
 
   return channel;

code/core/src/manager/App.tsx

@@ -7,6 +7,9 @@ import type { Addon_PageType } from 'storybook/internal/types';
 import { addons } from 'storybook/manager-api';
 import { Global, createGlobal } from 'storybook/theming';
 
+import { global } from '@storybook/global';
+
+import { isReviewFeatureEnabled } from '../shared/review/features.ts';
 import { ManagerErrorBoundary } from './components/error-boundary/ManagerErrorBoundary.tsx';
 import { Layout } from './components/layout/Layout.tsx';
 import { useLayout } from './components/layout/LayoutProvider.tsx';
@@ -80,7 +83,9 @@ export const App = ({ managerLayoutState, setManagerLayoutState, pages, hasTab }
           hasTab={hasTab}
           managerLayoutState={managerLayoutState}
           setManagerLayoutState={setManagerLayoutState}
-          slotOverlay={<ReviewPersistentLayer />}
+          slotOverlay={
+            isReviewFeatureEnabled(global.FEATURES) ? <ReviewPersistentLayer /> : undefined
+          }
           slotMain={<MainPreview />}
           slotSidebar={<Sidebar onMenuClick={() => setMobileAboutOpen((state) => !state)} />}
           slotPanel={<Panel />}

code/core/src/manager/components/preview/Preview.tsx

@@ -13,6 +13,7 @@ import { Helmet } from 'react-helmet-async';
 import { Consumer, addons, merge, types, type Combo } from 'storybook/manager-api';
 
 import { useLandmark } from '../../hooks/useLandmark.ts';
+import { isReviewFeatureEnabled } from '../../../shared/review/features.ts';
 import { isReviewCollectionStoryRoute } from '../../../shared/review/routes.ts';
 import { ReviewToolbarHeader } from '../review/components/ReviewToolbarHeader.tsx';
 import { FramesRenderer } from './FramesRenderer.tsx';
@@ -93,7 +94,8 @@ const Preview = React.memo<PreviewProps>(function Preview(props) {
   const shouldScale = viewMode === 'story';
   const { showToolbar } = options;
   const customisedShowToolbar = api.getShowToolbarWithCustomisations(showToolbar);
-  const isReviewCollectionStory = isReviewCollectionStoryRoute(path, queryParams);
+  const isReviewCollectionStory =
+    isReviewFeatureEnabled(global.FEATURES) && isReviewCollectionStoryRoute(path, queryParams);
 
   const previousStoryId = useRef(storyId);
 

code/core/src/shared/review/features.ts

@@ -0,0 +1,9 @@
+import type { StorybookFeatures } from '../../types/modules/core-common.ts';
+
+/**
+ * Whether the agentic review feature is enabled. Review is opt-in via the
+ * `experimentalReview` feature flag and builds on the change-detection pipeline, so it needs both
+ * flags. Mirrors the availability check MCP tooling uses to register review tools.
+ */
+export const isReviewFeatureEnabled = (features: StorybookFeatures | undefined): boolean =>
+  !!features?.experimentalReview && !!features?.changeDetection;

code/core/src/shared/review/index.ts

@@ -1,4 +1,5 @@
 export { REVIEW_EVENTS, REVIEW_NAMESPACE } from './events.ts';
+export { isReviewFeatureEnabled } from './features.ts';
 export type { ReviewPage, ReviewPageviewPayload } from './events.ts';
 export type { ReviewCollection, ReviewState } from './review-state.ts';
 export {