diff --git a/apps/stage-tamagotchi/package.json b/apps/stage-tamagotchi/package.json
index 82fd18d95..dfb8b3bb4 100644
--- a/apps/stage-tamagotchi/package.json
+++ b/apps/stage-tamagotchi/package.json
@@ -30,7 +30,6 @@
     "@stdlib/string-base-kebabcase": "^0.2.2",
     "@tauri-apps/api": "^2.6.0",
     "@tauri-apps/plugin-global-shortcut": "^2.3.0",
-    "@tauri-apps/plugin-os": "~2.3.0",
     "@tresjs/cientos": "^4.3.1",
     "@tresjs/core": "^4.3.6",
     "@vueuse/core": "^13.4.0",
diff --git a/apps/stage-tamagotchi/src/App.vue b/apps/stage-tamagotchi/src/App.vue
index 07a078a64..7d74ec950 100644
--- a/apps/stage-tamagotchi/src/App.vue
+++ b/apps/stage-tamagotchi/src/App.vue
@@ -1,8 +1,8 @@
 <script setup lang="ts">
+import { useAppRuntime } from '@proj-airi/stage-ui/composables'
 import { useMcpStore, useSettings } from '@proj-airi/stage-ui/stores'
 import { listen } from '@tauri-apps/api/event'
 import { Window } from '@tauri-apps/api/window'
-import { platform } from '@tauri-apps/plugin-os'
 import { useEventListener } from '@vueuse/core'
 import { storeToRefs } from 'pinia'
 import { computed, onMounted, watch } from 'vue'
@@ -15,6 +15,7 @@ const { language, themeColorsHue, themeColorsHueDynamic, allowVisibleOnAllWorksp
 const i18n = useI18n()
 const windowControlStore = useWindowControlStore()
 const mcpStore = useMcpStore()
+const { platform } = useAppRuntime()
 
 useEventListener(window, 'resize', () => {
   windowControlStore.size.width = window.innerWidth
@@ -41,7 +42,7 @@ listen('mcp_plugin_destroyed', () => {
   mcpStore.connected = false
 })
 
-const isMac = computed(() => platform() === 'macos')
+const isMac = computed(() => platform.value === 'macos')
 
 if (isMac.value) {
   watch(allowVisibleOnAllWorkspaces, async (value) => {
diff --git a/apps/stage-tamagotchi/src/components/Window/TitleBar.vue b/apps/stage-tamagotchi/src/components/Window/TitleBar.vue
index 321ee0304..0e809cfe0 100644
--- a/apps/stage-tamagotchi/src/components/Window/TitleBar.vue
+++ b/apps/stage-tamagotchi/src/components/Window/TitleBar.vue
@@ -1,10 +1,12 @@
 <script setup lang="ts">
-import { platform } from '@tauri-apps/plugin-os'
+import { useAppRuntime } from '@proj-airi/stage-ui/composables'
 
 defineProps<{
   title: string
   icon: string
 }>()
+
+const { platform } = useAppRuntime()
 </script>
 
 <template>
@@ -13,7 +15,7 @@ defineProps<{
     top="0"
     data-tauri-drag-region fixed z-100 w-full select-none py-2 pr-4
     :class="[
-      platform() === 'macos' ? 'pl-20' : 'pl-4',
+      platform === 'macos' ? 'pl-20' : 'pl-4',
     ]"
   >
     <div data-tauri-drag-region flex>
diff --git a/apps/stage-tamagotchi/src/pages/index.vue b/apps/stage-tamagotchi/src/pages/index.vue
index 221df6124..ea5e592d9 100644
--- a/apps/stage-tamagotchi/src/pages/index.vue
+++ b/apps/stage-tamagotchi/src/pages/index.vue
@@ -1,10 +1,10 @@
 <script setup lang="ts">
 import { WidgetStage } from '@proj-airi/stage-ui/components'
+import { useAppRuntime } from '@proj-airi/stage-ui/composables'
 import { useMcpStore } from '@proj-airi/stage-ui/stores'
 import { connectServer } from '@proj-airi/tauri-plugin-mcp'
 import { invoke } from '@tauri-apps/api/core'
 import { listen } from '@tauri-apps/api/event'
-import { platform } from '@tauri-apps/plugin-os'
 import { storeToRefs } from 'pinia'
 import { computed, onMounted, onUnmounted, ref } from 'vue'
 
@@ -13,6 +13,7 @@ import { useWindowControlStore } from '../stores/window-controls'
 import { WindowControlMode } from '../types/window-controls'
 import { startClickThrough, stopClickThrough } from '../utils/windows'
 
+const { platform } = useAppRuntime()
 const windowStore = useWindowControlStore()
 useWindowShortcuts()
 const isCursorInside = ref(false)
@@ -78,7 +79,7 @@ function onTauriPositionCursorAndWindowFrameEvent(event: { payload: [Point, Wind
   const [mouseLocation, windowFrame] = event.payload
   isCursorInside.value = mouseLocation.x >= windowFrame.origin.x && mouseLocation.x <= windowFrame.origin.x + windowFrame.size.width && mouseLocation.y >= windowFrame.origin.y && mouseLocation.y <= windowFrame.origin.y + windowFrame.size.height
 
-  if (platform() === 'macos') {
+  if (platform.value === 'macos') {
     live2dFocusAt.value = {
       x: mouseLocation.x - windowFrame.origin.x,
       y: windowFrame.size.height - mouseLocation.y + windowFrame.origin.y,
diff --git a/packages/stage-ui/src/composables/index.ts b/packages/stage-ui/src/composables/index.ts
index 478d703a4..e15d35dbe 100644
--- a/packages/stage-ui/src/composables/index.ts
+++ b/packages/stage-ui/src/composables/index.ts
@@ -3,5 +3,6 @@ export * from './markdown'
 export * from './micvad'
 export * from './queue'
 export * from './queues'
+export * from './runtime'
 export * from './vrm'
 export * from './whisper'
diff --git a/packages/stage-ui/src/composables/runtime.ts b/packages/stage-ui/src/composables/runtime.ts
new file mode 100644
index 000000000..edca51046
--- /dev/null
+++ b/packages/stage-ui/src/composables/runtime.ts
@@ -0,0 +1,54 @@
+import { computed } from 'vue'
+
+export function useTauri() {
+  const isTauri = computed(() => {
+    if ('window' in globalThis && globalThis.window != null) {
+      if ('__TAURI__' in globalThis.window && globalThis.window.__TAURI__ != null) {
+        return true
+      }
+    }
+
+    return false
+  })
+
+  return {
+    isTauri,
+    isWeb: computed(() => !isTauri.value),
+  }
+}
+
+export function useAppRuntime() {
+  const { isTauri, isWeb } = useTauri()
+  const platform = computed(() => {
+    if (isTauri.value) {
+      if ('window' in globalThis && globalThis.window != null) {
+        // https://github.com/tauri-apps/plugins-workspace/blob/fe01894e7f32a2a615081f62f612b755ea79f1c8/plugins/os/guest-js/index.ts#L66-L81
+        if ('__TAURI_OS_PLUGIN_INTERNALS__' in globalThis.window && globalThis.window.__TAURI_OS_PLUGIN_INTERNALS__ != null) {
+          const internal = globalThis.window.__TAURI_OS_PLUGIN_INTERNALS__ as Record<string, unknown>
+          return internal.platform || 'unknown'
+        }
+      }
+    }
+
+    return 'web'
+  })
+
+  const runtime = computed(() => {
+    if (isTauri.value) {
+      return 'tauri'
+    }
+    else if (isWeb.value) {
+      return 'web'
+    }
+    else {
+      return 'unknown'
+    }
+  })
+
+  return {
+    isTauri,
+    isWeb,
+    platform,
+    runtime,
+  }
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 4f8d84305..83785ba99 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -306,9 +306,6 @@ importers:
       '@tauri-apps/plugin-global-shortcut':
         specifier: ^2.3.0
         version: 2.3.0
-      '@tauri-apps/plugin-os':
-        specifier: ~2.3.0
-        version: 2.3.0
       '@tresjs/cientos':
         specifier: ^4.3.1
         version: 4.3.1(@tresjs/core@4.3.6(three@0.177.0)(typescript@5.8.3)(vue@3.5.17(typescript@5.8.3)))(@types/three@0.177.0)(react@18.3.1)(three@0.177.0)(typescript@5.8.3)(vue@3.5.17(typescript@5.8.3))
@@ -4793,9 +4790,6 @@ packages:
   '@tauri-apps/plugin-global-shortcut@2.3.0':
     resolution: {integrity: sha512-WbAz0ElhpP+0kzQZRScdCC7UQ7OPH8PAn//fsBNu7+ywihsnVSVOg1L9YhieAtLNtAlnmFI69Yl5AGaA3ge5IQ==}
 
-  '@tauri-apps/plugin-os@2.3.0':
-    resolution: {integrity: sha512-dm3bDsMuUngpIQdJ1jaMkMfyQpHyDcaTIKTFaAMHoKeUd+Is3UHO2uzhElr6ZZkfytIIyQtSVnCWdW2Kc58f3g==}
-
   '@tokenizer/token@0.3.0':
     resolution: {integrity: sha512-OvjF+z51L3ov0OyAU0duzsYuvO01PH7x4t6DJx+guahgTnBHkhJdG7soQeTSFLWN3efnHyibZ4Z8l2EuWwJN3A==}
 
@@ -15365,10 +15359,6 @@ snapshots:
     dependencies:
       '@tauri-apps/api': 2.6.0
 
-  '@tauri-apps/plugin-os@2.3.0':
-    dependencies:
-      '@tauri-apps/api': 2.6.0
-
   '@tokenizer/token@0.3.0': {}
 
   '@tresjs/cientos@4.3.1(@tresjs/core@4.3.6(three@0.177.0)(typescript@5.8.3)(vue@3.5.17(typescript@5.8.3)))(@types/three@0.177.0)(react@18.3.1)(three@0.177.0)(typescript@5.8.3)(vue@3.5.17(typescript@5.8.3))':