diff --git a/apps/stage-pocket/src/pages/index.vue b/apps/stage-pocket/src/pages/index.vue
index abe7e6405..33ddfd0e7 100644
--- a/apps/stage-pocket/src/pages/index.vue
+++ b/apps/stage-pocket/src/pages/index.vue
@@ -10,6 +10,7 @@ import workletUrl from '@proj-airi/stage-ui/workers/vad/process.worklet?worker&u
 import { BackgroundProvider } from '@proj-airi/stage-layouts/components/Backgrounds'
 import { useBackgroundThemeColor } from '@proj-airi/stage-layouts/composables/theme-color'
 import { useBackgroundStore } from '@proj-airi/stage-layouts/stores/background'
+import { IS_DEV } from '@proj-airi/stage-shared'
 import { WidgetStage } from '@proj-airi/stage-ui/components/scenes'
 import { useAudioRecorder } from '@proj-airi/stage-ui/composables/audio/audio-recorder'
 import { useVAD } from '@proj-airi/stage-ui/stores/ai/models/vad'
@@ -204,7 +205,7 @@ watch([stream, () => vadLoaded.value], async ([s, loaded]) => {
         />
         <InteractiveArea v-if="!isMobile" h="85dvh" absolute right-4 flex flex-1 flex-col max-w="500px" min-w="30%" />
         <MobileInteractiveArea v-if="isMobile" @settings-open="handleSettingsOpen">
-          <template v-if="import.meta.env.DEV" #status>
+          <template v-if="IS_DEV" #status>
             <WebSocketStatusButton />
           </template>
         </MobileInteractiveArea>
diff --git a/apps/stage-tamagotchi/src/renderer/pages/index.vue b/apps/stage-tamagotchi/src/renderer/pages/index.vue
index 7dd782eb4..878d8f297 100644
--- a/apps/stage-tamagotchi/src/renderer/pages/index.vue
+++ b/apps/stage-tamagotchi/src/renderer/pages/index.vue
@@ -14,6 +14,7 @@ import {
   useElectronMouseInWindow,
   useElectronRelativeMouse,
 } from '@proj-airi/electron-vueuse'
+import { IS_DEV } from '@proj-airi/stage-shared'
 import { useModelStore, useThreeSceneIsTransparentAtPoint } from '@proj-airi/stage-ui-three'
 import { HoloCoupon } from '@proj-airi/stage-ui/components'
 import {
@@ -474,7 +475,7 @@ watch([stream, () => vadLoaded.value], async ([s, loaded]) => {
           'transition-opacity duration-250 ease-in-out',
         ]"
       >
-        <StatusIsland v-if="import.meta.env.DEV" ref="statusIslandRef" />
+        <StatusIsland v-if="IS_DEV" ref="statusIslandRef" />
         <ResourceStatusIsland />
         <WidgetStage
           ref="widgetStageRef"
diff --git a/packages/stage-shared/src/environment.ts b/packages/stage-shared/src/environment.ts
index e34fe96e0..733859df6 100644
--- a/packages/stage-shared/src/environment.ts
+++ b/packages/stage-shared/src/environment.ts
@@ -4,6 +4,12 @@ export enum StageEnvironment {
   Tamagotchi = 'tamagotchi',
 }
 
+/**
+ * Build-time dev flag, replaced by Vite as a literal `true`/`false` so the
+ * unused branch is tree-shaken in production bundles.
+ */
+export const IS_DEV: boolean = import.meta.env.DEV
+
 export function isStageWeb(): boolean {
   return !import.meta.env.RUNTIME_ENVIRONMENT || import.meta.env.RUNTIME_ENVIRONMENT === 'browser'
 }