diff --git a/apps/desktop/src/i18n/en.ts b/apps/desktop/src/i18n/en.ts
index a1f7724d6c60..8e602867f902 100644
--- a/apps/desktop/src/i18n/en.ts
+++ b/apps/desktop/src/i18n/en.ts
@@ -132,6 +132,7 @@ export const en: Translations = {
     errors: {
       elevenLabsNeedsKey: 'ElevenLabs STT needs ELEVENLABS_API_KEY.',
       elevenLabsRejectedKey: 'ElevenLabs rejected the API key (401).',
+      gatewayAuthFailed: 'Gateway authentication failed — check your API_SERVER_KEY.',
       methodNotAllowed:
         'The desktop backend rejected that request (405 Method Not Allowed). Try restarting Hermes Desktop.',
       microphonePermission: 'Microphone permission was denied.',
diff --git a/apps/desktop/src/i18n/ja.ts b/apps/desktop/src/i18n/ja.ts
index 6d4bd9a89c52..d7dd7ec56510 100644
--- a/apps/desktop/src/i18n/ja.ts
+++ b/apps/desktop/src/i18n/ja.ts
@@ -133,6 +133,7 @@ export const ja = defineLocale({
     errors: {
       elevenLabsNeedsKey: 'ElevenLabs STT には ELEVENLABS_API_KEY が必要です。',
       elevenLabsRejectedKey: 'ElevenLabs が API キーを拒否しました (401)。',
+      gatewayAuthFailed: 'ゲートウェイ認証に失敗しました — API_SERVER_KEY を確認してください。',
       methodNotAllowed:
         'デスクトップバックエンドがそのリクエストを拒否しました (405 Method Not Allowed)。Hermes Desktop を再起動してください。',
       microphonePermission: 'マイクのアクセス許可が拒否されました。',
diff --git a/apps/desktop/src/i18n/types.ts b/apps/desktop/src/i18n/types.ts
index f71770813e00..65a93e3dda80 100644
--- a/apps/desktop/src/i18n/types.ts
+++ b/apps/desktop/src/i18n/types.ts
@@ -173,6 +173,7 @@ export interface Translations {
     errors: {
       elevenLabsNeedsKey: string
       elevenLabsRejectedKey: string
+      gatewayAuthFailed: string
       methodNotAllowed: string
       microphonePermission: string
       openaiRejectedApiKey: string
diff --git a/apps/desktop/src/i18n/zh-hant.ts b/apps/desktop/src/i18n/zh-hant.ts
index 919039f5504e..5229164c0a7a 100644
--- a/apps/desktop/src/i18n/zh-hant.ts
+++ b/apps/desktop/src/i18n/zh-hant.ts
@@ -129,6 +129,7 @@ export const zhHant = defineLocale({
     errors: {
       elevenLabsNeedsKey: 'ElevenLabs STT 需要 ELEVENLABS_API_KEY。',
       elevenLabsRejectedKey: 'ElevenLabs 拒絕了該 API 金鑰 (401)。',
+      gatewayAuthFailed: '閘道認證失敗 — 請檢查你的 API_SERVER_KEY。',
       methodNotAllowed: '桌面後端拒絕了該請求 (405 Method Not Allowed)。請嘗試重新啟動 Hermes Desktop。',
       microphonePermission: '麥克風權限已被拒絕。',
       openaiRejectedApiKey: 'OpenAI 拒絕了該 API 金鑰。',
diff --git a/apps/desktop/src/i18n/zh.ts b/apps/desktop/src/i18n/zh.ts
index 53cf3a93c2bf..297d5156f2a2 100644
--- a/apps/desktop/src/i18n/zh.ts
+++ b/apps/desktop/src/i18n/zh.ts
@@ -129,6 +129,7 @@ export const zh: Translations = {
     errors: {
       elevenLabsNeedsKey: 'ElevenLabs STT 需要 ELEVENLABS_API_KEY。',
       elevenLabsRejectedKey: 'ElevenLabs 拒绝了该 API key (401)。',
+      gatewayAuthFailed: '网关认证失败 — 请检查你的 API_SERVER_KEY。',
       methodNotAllowed: '桌面后端拒绝了该请求 (405 Method Not Allowed)。请尝试重启 Hermes Desktop。',
       microphonePermission: '麦克风权限已被拒绝。',
       openaiRejectedApiKey: 'OpenAI 拒绝了该 API key。',
diff --git a/apps/desktop/src/store/notifications.test.ts b/apps/desktop/src/store/notifications.test.ts
new file mode 100644
index 000000000000..49cb0b1024f6
--- /dev/null
+++ b/apps/desktop/src/store/notifications.test.ts
@@ -0,0 +1,34 @@
+import { beforeEach, expect, test } from 'vitest'
+
+import { $notifications, clearNotifications, notifyError } from './notifications'
+
+beforeEach(() => {
+  clearNotifications()
+})
+
+function lastMessage(): string {
+  return $notifications.get()[0]?.message ?? ''
+}
+
+// Regression for #39365: a gateway auth 401 (bad API_SERVER_KEY) must not be
+// summarized as a provider (OpenAI/OpenRouter) API key problem.
+test('gateway_auth_failed error is summarized as gateway auth, not provider key', () => {
+  notifyError(
+    new Error(
+      '401 {"error": {"message": "Invalid gateway API key (API_SERVER_KEY)", "type": "gateway_auth_error", "code": "gateway_auth_failed"}}'
+    ),
+    'Request failed'
+  )
+
+  expect(lastMessage()).toContain('API_SERVER_KEY')
+  expect(lastMessage()).not.toMatch(/OpenAI/i)
+})
+
+test('provider invalid_api_key error still maps to the OpenAI summary', () => {
+  notifyError(
+    new Error('401 {"error": {"message": "Incorrect API key provided", "code": "invalid_api_key"}}'),
+    'Request failed'
+  )
+
+  expect(lastMessage()).toMatch(/OpenAI rejected the API key/i)
+})
diff --git a/apps/desktop/src/store/notifications.ts b/apps/desktop/src/store/notifications.ts
index 97bfc31d541d..b0f8bb752c47 100644
--- a/apps/desktop/src/store/notifications.ts
+++ b/apps/desktop/src/store/notifications.ts
@@ -78,11 +78,11 @@ function cleanErrorText(value: string) {
 
 const ERROR_SUMMARIES: { test: (msg: string) => boolean; summarize: (msg: string) => string }[] = [
   {
-    test: msg => /['"']code['"']\s*:\s*['"']gateway_auth_failed['"']/i.test(msg),
-    summarize: () => 'Gateway authentication failed — check your API_SERVER_KEY.'
+    test: msg => /['"]code['"]\s*:\s*['"]gateway_auth_failed['"]/i.test(msg),
+    summarize: () => translateNow('notifications.errors.gatewayAuthFailed')
   },
   {
-    test: msg => /incorrect api key provided/i.test(msg) || /['"']code['"']\s*:\s*['"']invalid_api_key['"']/i.test(msg),
+    test: msg => /incorrect api key provided/i.test(msg) || /['"]code['"]\s*:\s*['"]invalid_api_key['"]/i.test(msg),
     summarize: msg => {
       const status = msg.match(/(?:error code|status(?:Code)?)[^\d]*(\d{3})/i)?.[1]