diff --git a/packages/stage-pages/src/pages/settings/providers/speech/kokoro-local.vue b/packages/stage-pages/src/pages/settings/providers/speech/kokoro-local.vue
index 732cfaa87..44f3cfce1 100644
--- a/packages/stage-pages/src/pages/settings/providers/speech/kokoro-local.vue
+++ b/packages/stage-pages/src/pages/settings/providers/speech/kokoro-local.vue
@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import type { SpeechProvider } from '@xsai-ext/providers/utils'
 
-import { getCachedWebGPUCapabilities, hasNavigatorWebGPU } from '@proj-airi/stage-shared/webgpu'
+import { getCachedWebGPUCapabilities } from '@proj-airi/stage-shared/webgpu'
 import {
   SpeechPlayground,
   SpeechProviderSettings,
@@ -104,7 +104,7 @@ onMounted(async () => {
   // NOTICE: Uses synchronous check for initial render. The cached result from
   // detectWebGPU() is populated by the providers store during initialization.
   const capabilities = getCachedWebGPUCapabilities()
-  hasWebGPU.value = capabilities?.supported ?? hasNavigatorWebGPU()
+  hasWebGPU.value = capabilities?.supported ?? (typeof navigator !== 'undefined' && !!navigator.gpu)
   fp16Supported.value = capabilities?.fp16Supported ?? false
 
   try {
diff --git a/packages/stage-shared/src/webgpu/detect.ts b/packages/stage-shared/src/webgpu/detect.ts
index 330e3373b..be4d933a5 100644
--- a/packages/stage-shared/src/webgpu/detect.ts
+++ b/packages/stage-shared/src/webgpu/detect.ts
@@ -7,14 +7,6 @@
 
 import { check as gpuuCheck, isWebGPUSupported as gpuuIsSupported } from 'gpuu/webgpu'
 
-interface NavigatorWebGPU {
-  requestAdapter: () => Promise<unknown>
-}
-
-interface NavigatorWithOptionalWebGPU extends Navigator {
-  gpu?: NavigatorWebGPU
-}
-
 export interface WebGPUCapabilities {
   /** Whether WebGPU is available in this environment */
   supported: boolean
@@ -29,50 +21,6 @@ export interface WebGPUCapabilities {
 let cachedResult: WebGPUCapabilities | null = null
 let pendingDetection: Promise<WebGPUCapabilities> | null = null
 
-/**
- * Returns the WebGPU navigator entry point when the current runtime exposes it.
- *
- * Use when:
- * - browser or worker code needs guarded access to WebGPU
- * - a caller only needs the `navigator.gpu` entry point, not a full capability probe
- *
- * Expects:
- * - browser-like runtimes where `navigator` may be unavailable during SSR or tests
- *
- * Returns:
- * - the WebGPU navigator entry point when available, otherwise `null`
- */
-export function getNavigatorWebGPU(): NavigatorWebGPU | null {
-  // NOTICE:
-  // TypeScript's default DOM libs in this repo do not declare `Navigator.gpu`.
-  // Direct `navigator.gpu` access fails in consumers like `@proj-airi/ui-server-auth`
-  // and in `@proj-airi/stage-ui` worker compilation even though the runtime guard is valid.
-  // We centralize the structural cast here until the repo opts into WebGPU ambient types.
-  // Removal condition: remove this helper once the workspace TypeScript config includes
-  // WebGPU navigator typings everywhere that imports these modules.
-  if (typeof navigator === 'undefined' || !('gpu' in navigator))
-    return null
-
-  return (navigator as NavigatorWithOptionalWebGPU).gpu ?? null
-}
-
-/**
- * Returns whether the current runtime exposes a WebGPU entry point on `navigator`.
- *
- * Use when:
- * - synchronous code only needs a fast boolean feature probe
- * - cached capability detection has not completed yet
- *
- * Expects:
- * - browser-like runtimes where `navigator` may be unavailable
- *
- * Returns:
- * - `true` when `navigator.gpu` is available, otherwise `false`
- */
-export function hasNavigatorWebGPU(): boolean {
-  return getNavigatorWebGPU() != null
-}
-
 /**
  * Detect WebGPU capabilities. The result is cached as a singleton
  * after the first successful call -- safe to call repeatedly.
diff --git a/packages/stage-shared/src/webgpu/index.ts b/packages/stage-shared/src/webgpu/index.ts
index f00428873..287e25d88 100644
--- a/packages/stage-shared/src/webgpu/index.ts
+++ b/packages/stage-shared/src/webgpu/index.ts
@@ -1,8 +1,6 @@
 export {
   detectWebGPU,
   getCachedWebGPUCapabilities,
-  getNavigatorWebGPU,
-  hasNavigatorWebGPU,
   isWebGPUSupported,
   resetWebGPUCache,
 } from './detect'
diff --git a/packages/stage-ui/src/libs/workers/worker.ts b/packages/stage-ui/src/libs/workers/worker.ts
index eaf30ae71..0ee1720c5 100644
--- a/packages/stage-ui/src/libs/workers/worker.ts
+++ b/packages/stage-ui/src/libs/workers/worker.ts
@@ -31,7 +31,6 @@ import {
   TextStreamer,
   WhisperForConditionalGeneration,
 } from '@huggingface/transformers'
-import { getNavigatorWebGPU } from '@proj-airi/stage-shared/webgpu'
 
 import { MODEL_IDS, MODEL_NAMES } from '../inference/constants'
 import { classifyError, isRecoverable } from '../inference/protocol'
@@ -76,10 +75,9 @@ const MODEL_ID = MODEL_IDS.WHISPER
  */
 async function detectWebGPUInWorker(): Promise<boolean> {
   try {
-    const webgpu = getNavigatorWebGPU()
-    if (!webgpu)
+    if (typeof navigator === 'undefined' || !navigator.gpu)
       return false
-    const adapter = await webgpu.requestAdapter()
+    const adapter = await navigator.gpu.requestAdapter()
     return adapter != null
   }
   catch {
diff --git a/packages/stage-ui/src/stores/providers.ts b/packages/stage-ui/src/stores/providers.ts
index 2538d1261..83644cb11 100644
--- a/packages/stage-ui/src/stores/providers.ts
+++ b/packages/stage-ui/src/stores/providers.ts
@@ -21,7 +21,7 @@ import type {
 import type { AliyunRealtimeSpeechExtraOptions } from './providers/aliyun/stream-transcription'
 
 import { isStageTamagotchi, isUrl } from '@proj-airi/stage-shared'
-import { getCachedWebGPUCapabilities, hasNavigatorWebGPU, isWebGPUSupported } from '@proj-airi/stage-shared/webgpu'
+import { getCachedWebGPUCapabilities, isWebGPUSupported } from '@proj-airi/stage-shared/webgpu'
 import { computedAsync, useIntervalFn, useLocalStorage } from '@vueuse/core'
 import {
   createOpenAI,
@@ -1715,7 +1715,7 @@ export const useProvidersStore = defineStore('providers', () => {
 
       defaultOptions: () => {
         const capabilities = getCachedWebGPUCapabilities()
-        const hasWebGPU = capabilities?.supported ?? hasNavigatorWebGPU()
+        const hasWebGPU = capabilities?.supported ?? (typeof navigator !== 'undefined' && !!navigator.gpu)
         const fp16Supported = capabilities?.fp16Supported ?? false
         const model = getDefaultKokoroModel(hasWebGPU, fp16Supported)
         return {
@@ -1772,7 +1772,7 @@ export const useProvidersStore = defineStore('providers', () => {
       capabilities: {
         listModels: async (_config: Record<string, unknown>) => {
           const caps = getCachedWebGPUCapabilities()
-          const hasWebGPU = caps?.supported ?? hasNavigatorWebGPU()
+          const hasWebGPU = caps?.supported ?? (typeof navigator !== 'undefined' && !!navigator.gpu)
           const fp16Supported = caps?.fp16Supported ?? false
           return kokoroModelsToModelInfo(hasWebGPU, t, fp16Supported)
         },
@@ -1791,7 +1791,7 @@ export const useProvidersStore = defineStore('providers', () => {
 
           // Validate platform requirements
           if (modelDef.platform === 'webgpu') {
-            const hasWebGPU = getCachedWebGPUCapabilities()?.supported ?? hasNavigatorWebGPU()
+            const hasWebGPU = getCachedWebGPUCapabilities()?.supported ?? (typeof navigator !== 'undefined' && !!navigator.gpu)
             if (!hasWebGPU) {
               throw new Error('WebGPU is required for this model but is not available in your browser')
             }
@@ -1835,7 +1835,7 @@ export const useProvidersStore = defineStore('providers', () => {
                   const modelDef = KOKORO_MODELS.find(m => m.id === modelId)
                   if (modelDef) {
                     if (modelDef.platform === 'webgpu') {
-                      const hasWebGPU = getCachedWebGPUCapabilities()?.supported ?? hasNavigatorWebGPU()
+                      const hasWebGPU = getCachedWebGPUCapabilities()?.supported ?? (typeof navigator !== 'undefined' && !!navigator.gpu)
                       if (!hasWebGPU) {
                         throw new Error('WebGPU is required for this model but is not available in your browser')
                       }
diff --git a/packages/stage-ui/src/workers/background-removal/worker.ts b/packages/stage-ui/src/workers/background-removal/worker.ts
index a40f0c196..66a59b152 100644
--- a/packages/stage-ui/src/workers/background-removal/worker.ts
+++ b/packages/stage-ui/src/workers/background-removal/worker.ts
@@ -18,7 +18,6 @@ import type {
 } from '../../libs/inference/protocol'
 
 import { AutoModel, AutoProcessor, env, RawImage } from '@huggingface/transformers'
-import { getNavigatorWebGPU } from '@proj-airi/stage-shared/webgpu'
 
 import { MODEL_IDS, MODEL_NAMES } from '../../libs/inference/constants'
 import { classifyError, isRecoverable } from '../../libs/inference/protocol'
@@ -81,10 +80,9 @@ function sendError(requestId: string, error: unknown, phase?: 'load' | 'inferenc
  */
 async function detectWebGPUInWorker(): Promise<boolean> {
   try {
-    const webgpu = getNavigatorWebGPU()
-    if (!webgpu)
+    if (typeof navigator === 'undefined' || !navigator.gpu)
       return false
-    const adapter = await webgpu.requestAdapter()
+    const adapter = await navigator.gpu.requestAdapter()
     return adapter != null
   }
   catch {