diff --git a/src/features/authFiles/components/AuthFilesPrefixProxyEditorModal.tsx b/src/features/authFiles/components/AuthFilesPrefixProxyEditorModal.tsx
index 85de3a0f..34295919 100644
--- a/src/features/authFiles/components/AuthFilesPrefixProxyEditorModal.tsx
+++ b/src/features/authFiles/components/AuthFilesPrefixProxyEditorModal.tsx
@@ -9,7 +9,10 @@ import type {
   PrefixProxyEditorFieldValue,
   PrefixProxyEditorState,
 } from '@/features/authFiles/hooks/useAuthFilesPrefixProxyEditor';
-import { supportsAuthFileWebsockets } from '@/features/authFiles/constants';
+import {
+  supportsAuthFileUsingApi,
+  supportsAuthFileWebsockets,
+} from '@/features/authFiles/constants';
 import styles from '@/pages/AuthFilesPage.module.scss';
 
 export type AuthFilesPrefixProxyEditorModalProps = {
@@ -155,6 +158,18 @@ export function AuthFilesPrefixProxyEditorModal(props: AuthFilesPrefixProxyEdito
                       <div className="hint">{t('auth_files.websockets_hint')}</div>
                     </div>
                   )}
+                  {supportsAuthFileUsingApi(editor.providerKey) && (
+                    <div className="form-group">
+                      <label>{t('auth_files.using_api_label')}</label>
+                      <ToggleSwitch
+                        checked={editor.usingApi}
+                        onChange={(value) => onChange('usingApi', value)}
+                        disabled={disableControls || editor.saving || !editor.json}
+                        ariaLabel={t('auth_files.using_api_label')}
+                      />
+                      <div className="hint">{t('auth_files.using_api_hint')}</div>
+                    </div>
+                  )}
                   <div className="form-group">
                     <label>{t('auth_files.headers_label')}</label>
                     <textarea
diff --git a/src/features/authFiles/constants.ts b/src/features/authFiles/constants.ts
index 088e8805..c28aa2d3 100644
--- a/src/features/authFiles/constants.ts
+++ b/src/features/authFiles/constants.ts
@@ -54,6 +54,7 @@ export const INTEGER_STRING_PATTERN = /^[+-]?\d+$/;
 export const TRUTHY_TEXT_VALUES = new Set(['true', '1', 'yes', 'y', 'on']);
 export const FALSY_TEXT_VALUES = new Set(['false', '0', 'no', 'n', 'off']);
 export const AUTH_FILE_WEBSOCKET_PROVIDERS = new Set(['codex', 'xai']);
+export const AUTH_FILE_USING_API_PROVIDERS = new Set(['xai']);
 
 // 标签类型颜色配置 — 基于各提供商 Logo 品牌色调配，确保彼此不重复
 export const TYPE_COLORS: Record<string, TypeColorSet> = {
@@ -236,6 +237,17 @@ export const applyAuthFileWebsockets = (
   return next;
 };
 
+export const supportsAuthFileUsingApi = (providerKey: string): boolean =>
+  AUTH_FILE_USING_API_PROVIDERS.has(normalizeProviderKey(providerKey));
+
+export const readAuthFileUsingApi = (value: Record<string, unknown>): boolean =>
+  parseDisableCoolingValue(value.using_api) ?? false;
+
+export const applyAuthFileUsingApi = (
+  value: Record<string, unknown>,
+  usingApi: boolean
+): Record<string, unknown> => ({ ...value, using_api: usingApi });
+
 export function isRuntimeOnlyAuthFile(file: AuthFileItem): boolean {
   const raw = file['runtime_only'] ?? file.runtimeOnly;
   if (typeof raw === 'boolean') return raw;
diff --git a/src/features/authFiles/hooks/useAuthFilesPrefixProxyEditor.ts b/src/features/authFiles/hooks/useAuthFilesPrefixProxyEditor.ts
index dcdeda2a..a46d27fb 100644
--- a/src/features/authFiles/hooks/useAuthFilesPrefixProxyEditor.ts
+++ b/src/features/authFiles/hooks/useAuthFilesPrefixProxyEditor.ts
@@ -5,10 +5,13 @@ import type { AuthFileItem } from '@/types';
 import { useNotificationStore } from '@/stores';
 import {
   applyAuthFileWebsockets,
+  applyAuthFileUsingApi,
   normalizeProviderKey,
   parsePriorityValue,
   readAuthFileWebsockets,
+  readAuthFileUsingApi,
   supportsAuthFileWebsockets,
+  supportsAuthFileUsingApi,
 } from '@/features/authFiles/constants';
 
 type AuthFileHeaders = Record<string, string>;
@@ -25,6 +28,7 @@ export type PrefixProxyEditorField =
   | 'proxyUrl'
   | 'priority'
   | 'websockets'
+  | 'usingApi'
   | 'note'
   | 'headersText';
 
@@ -46,6 +50,8 @@ export type PrefixProxyEditorState = {
   priority: string;
   websockets: boolean;
   websocketsTouched: boolean;
+  usingApi: boolean;
+  usingApiTouched: boolean;
   note: string;
   noteTouched: boolean;
   headersText: string;
@@ -265,6 +271,14 @@ const buildAuthFileFieldsPatch = (
     }
   }
 
+  if (supportsAuthFileUsingApi(editor.providerKey) && editor.usingApiTouched) {
+    const originalUsingApi = readAuthFileUsingApi(original);
+    const nextUsingApi = Boolean(editor.usingApi);
+    if (nextUsingApi !== originalUsingApi) {
+      patch.using_api = nextUsingApi;
+    }
+  }
+
   if (editor.headersTouched) {
     const { value: parsedHeaders, errorKey } = parseHeadersText(editor.headersText);
     if (errorKey) {
@@ -326,6 +340,10 @@ const buildPrefixProxyUpdatedText = (
     next = applyAuthFileWebsockets(next, patch.websockets);
   }
 
+  if (patch.using_api !== undefined) {
+    next = applyAuthFileUsingApi(next, patch.using_api);
+  }
+
   return JSON.stringify(next);
 };
 
@@ -383,6 +401,8 @@ export function useAuthFilesPrefixProxyEditor(
       priority: '',
       websockets: false,
       websocketsTouched: false,
+      usingApi: false,
+      usingApiTouched: false,
       note: '',
       noteTouched: false,
       headersText: '',
@@ -430,6 +450,7 @@ export function useAuthFilesPrefixProxyEditor(
       const websockets = supportsAuthFileWebsockets(providerKey)
         ? readAuthFileWebsockets(json)
         : false;
+      const usingApi = supportsAuthFileUsingApi(providerKey) ? readAuthFileUsingApi(json) : false;
       const note = typeof json.note === 'string' ? json.note : '';
       const headers = json.headers;
       let headersText = '';
@@ -455,6 +476,8 @@ export function useAuthFilesPrefixProxyEditor(
           priority: priority !== undefined ? String(priority) : '',
           websockets,
           websocketsTouched: false,
+          usingApi,
+          usingApiTouched: false,
           note,
           noteTouched: false,
           headersText,
@@ -485,6 +508,9 @@ export function useAuthFilesPrefixProxyEditor(
       if (field === 'websockets') {
         return { ...prev, websockets: Boolean(value), websocketsTouched: true };
       }
+      if (field === 'usingApi') {
+        return { ...prev, usingApi: Boolean(value), usingApiTouched: true };
+      }
       if (field === 'note') return { ...prev, note: String(value), noteTouched: true };
       if (field === 'headersText') {
         const headersText = String(value);
diff --git a/src/i18n/locales/en.json b/src/i18n/locales/en.json
index 4fbb99f4..8293ce2b 100644
--- a/src/i18n/locales/en.json
+++ b/src/i18n/locales/en.json
@@ -282,6 +282,8 @@
     "priority_hint": "Integers only. Invalid values are ignored. Larger value means higher priority.",
     "websockets_label": "WebSockets (websockets)",
     "websockets_hint": "Enable Responses API websocket transport for this credential.",
+    "using_api_label": "Use official API (using_api)",
+    "using_api_hint": "Use the official xAI API when enabled; use Grok CLI chat-proxy when disabled.",
     "note_label": "Note",
     "note_placeholder": "Enter a note, e.g.: John's account",
     "note_hint": "Optional. Used to describe the purpose or owner of this credential; leave empty to omit.",
diff --git a/src/i18n/locales/ru.json b/src/i18n/locales/ru.json
index 52b4fbb4..e7c7af7f 100644
--- a/src/i18n/locales/ru.json
+++ b/src/i18n/locales/ru.json
@@ -281,6 +281,8 @@
     "priority_hint": "Только целые числа. Некорректные значения игнорируются. Чем больше число, тем выше приоритет.",
     "websockets_label": "WebSockets (websockets)",
     "websockets_hint": "Включает websocket-транспорт Responses API для этих учётных данных.",
+    "using_api_label": "Использовать официальный API (using_api)",
+    "using_api_hint": "Если включено, используется официальный API xAI; если выключено — Grok CLI chat-proxy.",
     "note_label": "Заметка (note)",
     "note_placeholder": "Введите заметку, например: аккаунт Ивана",
     "note_hint": "Необязательно. Используется для описания назначения или владельца учётных данных; оставьте пустым, чтобы не записывать.",
diff --git a/src/i18n/locales/zh-CN.json b/src/i18n/locales/zh-CN.json
index 2f9cd4f5..24969219 100644
--- a/src/i18n/locales/zh-CN.json
+++ b/src/i18n/locales/zh-CN.json
@@ -282,6 +282,8 @@
     "priority_hint": "仅支持整数；非法值会被忽略。数值越大优先级越高。",
     "websockets_label": "WebSockets（websockets）",
     "websockets_hint": "为该凭证开启 Responses API 的 websocket 传输。",
+    "using_api_label": "使用官方 API（using_api）",
+    "using_api_hint": "开启后使用 xAI 官方 API；关闭时使用 Grok CLI chat-proxy。",
     "note_label": "备注（note）",
     "note_placeholder": "输入备注信息，例如：张三的账号",
     "note_hint": "可选，用于标记凭证用途或归属；留空则不写入。",
diff --git a/src/i18n/locales/zh-TW.json b/src/i18n/locales/zh-TW.json
index 08a7c647..abd98892 100644
--- a/src/i18n/locales/zh-TW.json
+++ b/src/i18n/locales/zh-TW.json
@@ -282,6 +282,8 @@
     "priority_hint": "僅支援整數；無效值會被忽略。數值越大優先順序越高。",
     "websockets_label": "WebSockets（websockets）",
     "websockets_hint": "為該憑證開啟 Responses API 的 websocket 傳輸。",
+    "using_api_label": "使用官方 API（using_api）",
+    "using_api_hint": "開啟後使用 xAI 官方 API；關閉時使用 Grok CLI chat-proxy。",
     "note_label": "備註（note）",
     "note_placeholder": "輸入備註資訊，例如：張三的帳號",
     "note_hint": "選填，用於標記憑證用途或歸屬；留空則不寫入。",
diff --git a/src/services/api/authFiles.ts b/src/services/api/authFiles.ts
index 431ad2fd..5ddac9c5 100644
--- a/src/services/api/authFiles.ts
+++ b/src/services/api/authFiles.ts
@@ -17,6 +17,7 @@ export type AuthFileFieldsPatch = {
   headers?: Record<string, string>;
   priority?: number;
   websockets?: boolean;
+  using_api?: boolean;
   note?: string;
 };
 type AuthFileBatchFailure = { name: string; error: string };
diff --git a/tests/xaiUsingApiAuthFile.test.ts b/tests/xaiUsingApiAuthFile.test.ts
new file mode 100644
index 00000000..8576b651
--- /dev/null
+++ b/tests/xaiUsingApiAuthFile.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, test } from 'bun:test';
+import {
+  applyAuthFileUsingApi,
+  readAuthFileUsingApi,
+  supportsAuthFileUsingApi,
+} from '@/features/authFiles/constants';
+
+describe('xAI auth-file using_api', () => {
+  test('is only exposed for xAI credentials', () => {
+    expect(supportsAuthFileUsingApi('xai')).toBe(true);
+    expect(supportsAuthFileUsingApi('grok')).toBe(true);
+    expect(supportsAuthFileUsingApi('codex')).toBe(false);
+  });
+
+  test('reads boolean-compatible values and defaults to chat-proxy mode', () => {
+    expect(readAuthFileUsingApi({ using_api: true })).toBe(true);
+    expect(readAuthFileUsingApi({ using_api: 'true' })).toBe(true);
+    expect(readAuthFileUsingApi({ using_api: false })).toBe(false);
+    expect(readAuthFileUsingApi({})).toBe(false);
+  });
+
+  test('writes an explicit using_api boolean', () => {
+    expect(applyAuthFileUsingApi({ type: 'xai' }, true)).toEqual({
+      type: 'xai',
+      using_api: true,
+    });
+    expect(applyAuthFileUsingApi({ type: 'xai', using_api: true }, false)).toEqual({
+      type: 'xai',
+      using_api: false,
+    });
+  });
+});