diff --git a/frontend/src/components/account/CreateAccountModal.vue b/frontend/src/components/account/CreateAccountModal.vue
index 665c46955..5f5a11d73 100644
--- a/frontend/src/components/account/CreateAccountModal.vue
+++ b/frontend/src/components/account/CreateAccountModal.vue
@@ -2692,10 +2692,18 @@
             <Select
               v-model="openAIResponsesMode"
               :options="openAIResponsesModeOptions"
+              :disabled="!openAITextGenerationCapabilityEnabled"
               data-testid="openai-responses-mode-select"
             />
           </div>
         </div>
+        <p
+          v-if="!openAITextGenerationCapabilityEnabled"
+          class="rounded-lg bg-amber-50 px-3 py-2 text-xs text-amber-700 dark:bg-amber-900/20 dark:text-amber-300"
+          data-testid="openai-responses-mode-not-applicable"
+        >
+          {{ t('admin.accounts.openai.responsesModeTextDisabledHint') }}
+        </p>
         <div>
           <label class="input-label mb-2 block">{{ t('admin.accounts.openai.endpointCapabilities') }}</label>
           <div class="grid grid-cols-1 gap-2 sm:grid-cols-2">
@@ -3434,10 +3442,22 @@ const openAIResponsesModeOptions = computed(() => [
   { value: 'force_responses', label: t('admin.accounts.openai.responsesModeForceResponses') },
   { value: 'force_chat_completions', label: t('admin.accounts.openai.responsesModeForceChatCompletions') }
 ])
+const openAITextEndpointCapabilityLabel = computed(() => {
+  if (openAIResponsesMode.value === 'force_responses') {
+    return t('admin.accounts.openai.capabilityResponses')
+  }
+  if (openAIResponsesMode.value === 'force_chat_completions') {
+    return t('admin.accounts.openai.capabilityChatCompletions')
+  }
+  return t('admin.accounts.openai.capabilityTextAuto')
+})
 const openAIEndpointCapabilityOptions = computed<{ value: OpenAIEndpointCapability; label: string }[]>(() => [
-  { value: 'chat_completions', label: t('admin.accounts.openai.capabilityChatCompletions') },
+  { value: 'chat_completions', label: openAITextEndpointCapabilityLabel.value },
   { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') }
 ])
+const openAITextGenerationCapabilityEnabled = computed(() =>
+  openAIEndpointCapabilities.value.includes('chat_completions')
+)
 
 const normalizeOpenAIEndpointCapabilities = (values: OpenAIEndpointCapability[]) => {
   const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings']
@@ -3455,6 +3475,9 @@ const toggleOpenAIEndpointCapability = (capability: OpenAIEndpointCapability, ev
     openAIEndpointCapabilities.value = openAIEndpointCapabilities.value.filter(
       (value) => value !== capability
     )
+    if (!openAITextGenerationCapabilityEnabled.value) {
+      openAIResponsesMode.value = 'auto'
+    }
     return
   }
   openAIEndpointCapabilities.value = normalizeOpenAIEndpointCapabilities([
@@ -4268,7 +4291,11 @@ const buildOpenAIExtra = (base?: Record<string, unknown>): Record<string, unknow
     delete extra.openai_compact_mode
   }
 
-  if (accountCategory.value === 'apikey' && openAIResponsesMode.value !== 'auto') {
+  if (
+    accountCategory.value === 'apikey' &&
+    openAITextGenerationCapabilityEnabled.value &&
+    openAIResponsesMode.value !== 'auto'
+  ) {
     extra.openai_responses_mode = openAIResponsesMode.value
   } else {
     delete extra.openai_responses_mode
diff --git a/frontend/src/components/account/EditAccountModal.vue b/frontend/src/components/account/EditAccountModal.vue
index 3cb105910..1f7ab7d38 100644
--- a/frontend/src/components/account/EditAccountModal.vue
+++ b/frontend/src/components/account/EditAccountModal.vue
@@ -1452,13 +1452,24 @@
             <Select
               v-model="openAIResponsesMode"
               :options="openAIResponsesModeOptions"
+              :disabled="!openAITextGenerationCapabilityEnabled"
               data-testid="openai-responses-mode-select"
             />
           </div>
         </div>
-        <div class="rounded-lg bg-gray-50 px-3 py-2 text-xs text-gray-600 dark:bg-dark-700 dark:text-gray-300">
+        <div
+          v-if="openAITextGenerationCapabilityEnabled"
+          class="rounded-lg bg-gray-50 px-3 py-2 text-xs text-gray-600 dark:bg-dark-700 dark:text-gray-300"
+        >
           <span class="font-medium">{{ t(openAIResponsesStatusKey) }}</span>
         </div>
+        <div
+          v-else
+          class="rounded-lg bg-amber-50 px-3 py-2 text-xs text-amber-700 dark:bg-amber-900/20 dark:text-amber-300"
+          data-testid="openai-responses-mode-not-applicable"
+        >
+          {{ t('admin.accounts.openai.responsesModeTextDisabledHint') }}
+        </div>
         <div>
           <label class="input-label mb-2 block">{{ t('admin.accounts.openai.endpointCapabilities') }}</label>
           <div class="grid grid-cols-1 gap-2 sm:grid-cols-2">
@@ -2568,10 +2579,29 @@ const openAIResponsesModeOptions = computed(() => [
   { value: 'force_responses', label: t('admin.accounts.openai.responsesModeForceResponses') },
   { value: 'force_chat_completions', label: t('admin.accounts.openai.responsesModeForceChatCompletions') }
 ])
+const openAITextEndpointCapabilityLabel = computed(() => {
+  if (openAIResponsesMode.value === 'force_responses') {
+    return t('admin.accounts.openai.capabilityResponses')
+  }
+  if (openAIResponsesMode.value === 'force_chat_completions') {
+    return t('admin.accounts.openai.capabilityChatCompletions')
+  }
+  const extra = props.account?.extra as Record<string, unknown> | undefined
+  if (extra?.openai_responses_supported === true) {
+    return t('admin.accounts.openai.capabilityResponsesAuto')
+  }
+  if (extra?.openai_responses_supported === false) {
+    return t('admin.accounts.openai.capabilityChatCompletionsAuto')
+  }
+  return t('admin.accounts.openai.capabilityTextAuto')
+})
 const openAIEndpointCapabilityOptions = computed<{ value: OpenAIEndpointCapability; label: string }[]>(() => [
-  { value: 'chat_completions', label: t('admin.accounts.openai.capabilityChatCompletions') },
+  { value: 'chat_completions', label: openAITextEndpointCapabilityLabel.value },
   { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') }
 ])
+const openAITextGenerationCapabilityEnabled = computed(() =>
+  openAIEndpointCapabilities.value.includes('chat_completions')
+)
 
 const normalizeOpenAIEndpointCapabilities = (values: OpenAIEndpointCapability[]) => {
   const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings']
@@ -2609,6 +2639,9 @@ const toggleOpenAIEndpointCapability = (capability: OpenAIEndpointCapability, ev
     openAIEndpointCapabilities.value = openAIEndpointCapabilities.value.filter(
       (value) => value !== capability
     )
+    if (!openAITextGenerationCapabilityEnabled.value) {
+      openAIResponsesMode.value = 'auto'
+    }
     return
   }
   openAIEndpointCapabilities.value = normalizeOpenAIEndpointCapabilities([
@@ -2826,6 +2859,9 @@ const syncFormFromAccount = (newAccount: Account | null) => {
       openAIEndpointCapabilities.value = readOpenAIEndpointCapabilities(
         newAccount.credentials as Record<string, unknown> | undefined
       )
+      if (!openAITextGenerationCapabilityEnabled.value) {
+        openAIResponsesMode.value = 'auto'
+      }
     }
     const codexImageGenerationBridgeValue = typeof extra?.codex_image_generation_bridge === 'boolean'
       ? extra.codex_image_generation_bridge
@@ -3945,7 +3981,7 @@ const handleSubmit = async () => {
         newExtra.openai_compact_mode = openAICompactMode.value
       }
       if (props.account.type === 'apikey') {
-        if (openAIResponsesMode.value === 'auto') {
+        if (!openAITextGenerationCapabilityEnabled.value || openAIResponsesMode.value === 'auto') {
           delete newExtra.openai_responses_mode
         } else {
           newExtra.openai_responses_mode = openAIResponsesMode.value
diff --git a/frontend/src/components/account/__tests__/EditAccountModal.spec.ts b/frontend/src/components/account/__tests__/EditAccountModal.spec.ts
index db012a308..4561924f6 100644
--- a/frontend/src/components/account/__tests__/EditAccountModal.spec.ts
+++ b/frontend/src/components/account/__tests__/EditAccountModal.spec.ts
@@ -367,6 +367,37 @@ describe('EditAccountModal', () => {
     ])
   })
 
+  it('disables text generation protocol when only embeddings requests are accepted', async () => {
+    const account = buildAccount()
+    account.credentials.openai_capabilities = ['embeddings']
+    account.extra = {
+      openai_responses_mode: 'force_responses',
+      openai_responses_supported: true
+    }
+    updateAccountMock.mockReset()
+    checkMixedChannelRiskMock.mockReset()
+    checkMixedChannelRiskMock.mockResolvedValue({ has_risk: false })
+    updateAccountMock.mockResolvedValue(account)
+
+    const wrapper = mountModal(account)
+
+    const responsesModeSelect = wrapper.get<HTMLSelectElement>(
+      '[data-testid="openai-responses-mode-select"]'
+    )
+
+    expect(responsesModeSelect.element.disabled).toBe(true)
+    expect(wrapper.find('[data-testid="openai-responses-mode-not-applicable"]').exists()).toBe(true)
+
+    await wrapper.get('form#edit-account-form').trigger('submit.prevent')
+
+    expect(updateAccountMock).toHaveBeenCalledTimes(1)
+    expect(updateAccountMock.mock.calls[0]?.[1]?.credentials?.openai_capabilities).toEqual([
+      'embeddings'
+    ])
+    expect(updateAccountMock.mock.calls[0]?.[1]?.extra).not.toHaveProperty('openai_responses_mode')
+    expect(updateAccountMock.mock.calls[0]?.[1]?.extra?.openai_responses_supported).toBe(true)
+  })
+
   it('submits account-level Codex image generation bridge override', async () => {
     const account = buildAccount()
     account.extra = {
diff --git a/frontend/src/i18n/locales/en.ts b/frontend/src/i18n/locales/en.ts
index ec659dd44..168e7129e 100644
--- a/frontend/src/i18n/locales/en.ts
+++ b/frontend/src/i18n/locales/en.ts
@@ -3349,14 +3349,20 @@ export default {
           'Automatic passthrough is currently enabled: it only affects HTTP passthrough and does not disable WS mode.',
         responsesMode: 'Responses API support',
         responsesModeDesc:
-          'Only applies to OpenAI API Key accounts. Auto follows probe results; force modes override probing.',
+          'Only applies to the OpenAI API Key text forwarding path. Auto follows probe results; force modes override probing.',
         responsesModeAuto: 'Auto',
         responsesModeForceResponses: 'Force Responses',
         responsesModeForceChatCompletions: 'Force Chat Completions',
+        responsesModeTextDisabledHint:
+          'Not applicable when the Responses / Chat Completions endpoint is not enabled.',
         endpointCapabilities: 'Endpoint capabilities',
         endpointCapabilitiesDesc:
-          'Used by account routing. Both endpoints are allowed by default; if the upstream only supports one, select only the supported endpoint.',
+          'Used by account routing. The text endpoint follows the Responses API support setting above and is shown as Responses, Chat Completions, or auto mode; Embeddings independently controls /v1/embeddings.',
+        capabilityResponses: 'Responses',
+        capabilityTextAuto: 'Responses / Chat Completions (Auto)',
+        capabilityResponsesAuto: 'Responses (auto probe)',
         capabilityChatCompletions: 'Chat Completions',
+        capabilityChatCompletionsAuto: 'Chat Completions (auto probe)',
         capabilityEmbeddings: 'Embeddings',
         responsesStatusAutoSupported: 'Auto probe: Responses',
         responsesStatusAutoUnsupported: 'Auto probe: Chat Completions',
diff --git a/frontend/src/i18n/locales/zh.ts b/frontend/src/i18n/locales/zh.ts
index 36b0d8c34..adf3dcaf2 100644
--- a/frontend/src/i18n/locales/zh.ts
+++ b/frontend/src/i18n/locales/zh.ts
@@ -3495,14 +3495,19 @@ export default {
         responsesWebsocketsV2PassthroughHint: '当前已开启自动透传：仅影响 HTTP 透传链路，不影响 WS mode。',
         responsesMode: 'Responses API 支持',
         responsesModeDesc:
-          '仅对 OpenAI API Key 生效。自动跟随探测结果，强制模式会覆盖自动探测。',
+          '仅对 OpenAI API Key 的文本转发链路生效。自动跟随探测结果，强制模式会覆盖自动探测。',
         responsesModeAuto: '自动',
         responsesModeForceResponses: '强制 Responses',
         responsesModeForceChatCompletions: '强制 Chat Completions',
+        responsesModeTextDisabledHint: '未启用 Responses / Chat Completions 端点时，此设置不适用。',
         endpointCapabilities: '端点能力',
         endpointCapabilitiesDesc:
-          '用于调度筛选。默认两个端点都可用；如果上游只支持其中一个，请只勾选实际支持的端点。',
+          '用于调度筛选。文本端点会跟随上方 Responses API 支持显示为 Responses、Chat Completions 或自动模式；Embeddings 独立控制 /v1/embeddings。',
+        capabilityResponses: 'Responses',
+        capabilityTextAuto: 'Responses / Chat Completions（自动）',
+        capabilityResponsesAuto: 'Responses（自动探测）',
         capabilityChatCompletions: 'Chat Completions',
+        capabilityChatCompletionsAuto: 'Chat Completions（自动探测）',
         capabilityEmbeddings: 'Embeddings',
         responsesStatusAutoSupported: '自动探测：Responses',
         responsesStatusAutoUnsupported: '自动探测：Chat Completions',