diff --git a/ui/src/api/API_README.md b/ui/src/api/API_README.md
index 95259558ae6..6e1bbd6c3a8 100644
--- a/ui/src/api/API_README.md
+++ b/ui/src/api/API_README.md
@@ -5,6 +5,7 @@ Admin API；Chat 目录作为独立体系预留。
 
 ```text
 src/api/
+├── constants.ts                     # Admin 与 Chat 的 API base 路径常量
 ├── admin/
 │   ├── auth/                         # Admin 登录认证与当前用户接口
 │   │   └── types.ts                  # 认证 API 与认证 Store 共用类型
@@ -154,8 +155,12 @@ API 枚举与类型统一在 `src/api` 范围内管理，相关规则由本文
 
 ## 请求约定
 
-- Admin 业务接口只声明相对资源路径，`/admin/api` 等部署前缀由 `core/request.ts` 统一处理。
-- Admin Router 与请求客户端直接读取 `window.MaxKB` 运行时路径配置；`Window` 和
+- `constants.ts` 统一导出 `ADMIN_API_BASE_PATH` 和 `CHAT_API_BASE_PATH`，分别优先读取
+  `window.MaxKB.prefix` 和 `window.MaxKB.chatPrefix`，再回退到 `VITE_BASE_PATH` 和各自默认路径；
+  去掉末尾斜杠后追加 `/api`。Admin、Chat 请求客户端和会话流式请求复用这些常量。
+- Admin 普通业务接口只声明相对资源路径，由 `core/request.ts` 的 Axios baseURL 处理部署前缀；
+  流式接口显式传入对应的 API base 常量。
+- Admin Router 直接读取 `window.MaxKB` 运行时路径配置，请求客户端通过上述常量读取；`Window` 和
   `MaxKBRuntimeConfig` 的全局类型统一声明在根目录 `env.d.ts`。
 - Admin 普通 JSON 请求使用 Axios；`request.ts` 导出 Axios 实例以及 `promise`、`get`、
   `post`、`put`、`del`、流式响应 `postStream` 和 Blob 文件 `downloadRequest` 请求封装。
@@ -171,6 +176,7 @@ API 枚举与类型统一在 `src/api` 范围内管理，相关规则由本文
   登录页。
 - loading 不作为 API 函数参数，由调用接口的页面或 Store 管理。
 - 流式 POST 请求使用 `postStream` 返回原始 `Response`，由业务组件按具体协议解析数据块；
+  参数顺序为 `postStream(base, path, data?, config?)`，`config.signal` 用于取消请求。
   鉴权、语言请求头和错误状态仍由请求基础设施统一处理。
 - 上传、下载和其他特殊请求在真实需求出现时独立设计，不提前塞入普通 JSON 请求客户端。
 
diff --git a/ui/src/api/admin/core/request.ts b/ui/src/api/admin/core/request.ts
index 5fbcfbb6f54..7c85eaddfff 100644
--- a/ui/src/api/admin/core/request.ts
+++ b/ui/src/api/admin/core/request.ts
@@ -6,9 +6,9 @@ import { useStore } from '@/stores'
 import type { ApiResponse, LoadingTarget } from './types'
 import type { Dict } from '@/api/types'
 import { MsgError } from '@/utils/message'
+import { ADMIN_API_BASE_PATH } from '@/api/constants'
 
 const DEFAULT_TIMEOUT = 30 * 60 * 1_000 // 30 minutes
-const ADMIN_BASE_PATH = window.MaxKB?.prefix || import.meta.env.VITE_BASE_PATH || '/admin/'
 
 interface ExportRequestConfig extends AxiosRequestConfig {
   skipGlobalErrorMessage?: boolean
@@ -128,7 +128,7 @@ async function downloadExportResponse(response: AxiosResponse<Blob>, fileName: s
   return true
 }
 
-export const request = axios.create({ baseURL: `${ADMIN_BASE_PATH.replace(/\/+$/, '')}/api`, timeout: DEFAULT_TIMEOUT, withCredentials: false })
+export const request = axios.create({ baseURL: ADMIN_API_BASE_PATH, timeout: DEFAULT_TIMEOUT, withCredentials: false })
 
 request.interceptors.request.use(setRequestHeaders)
 
@@ -195,29 +195,9 @@ export function get<T = unknown>(url: string, params?: Dict<unknown>, loading?:
   return promise<T>(request.get<ApiResponse<T>>(url, { params, timeout }), loading)
 }
 
-/** 发送指定方法的 Blob 请求并触发浏览器下载。 */
-export async function downloadRequest(
-  url: string,
-  method: string,
-  data?: unknown,
-  params?: Dict<unknown>,
-  loading?: LoadingTarget,
-): Promise<boolean> {
-  startLoading(loading)
-  try {
-    const response = await request.request<Blob>({
-      url,
-      method,
-      data,
-      params,
-      responseType: 'blob',
-      skipGlobalErrorMessage: true,
-    } as ExportRequestConfig)
-
-    return downloadExportResponse(response, 'download')
-  } finally {
-    finishLoading(loading)
-  }
+/** 发送 POST 请求。 */
+export function post<TData = unknown, T = unknown>(url: string, data?: TData, params?: Dict<unknown>, loading?: LoadingTarget, timeout?: number) {
+  return promise<T>(request.post<ApiResponse<T>>(url, data, { params, timeout }), loading)
 }
 
 /** 发送 GET 请求并将 Blob 响应下载为文件。 */
@@ -250,13 +230,33 @@ export async function postExportExcel<TData = unknown>(
   }
 }
 
-/** 发送 POST 请求。 */
-export function post<TData = unknown, T = unknown>(url: string, data?: TData, params?: Dict<unknown>, loading?: LoadingTarget, timeout?: number) {
-  return promise<T>(request.post<ApiResponse<T>>(url, data, { params, timeout }), loading)
+/** 发送指定方法的 Blob 请求并触发浏览器下载。 */
+export async function downloadRequest(
+  url: string,
+  method: string,
+  data?: unknown,
+  params?: Dict<unknown>,
+  loading?: LoadingTarget,
+): Promise<boolean> {
+  startLoading(loading)
+  try {
+    const response = await request.request<Blob>({
+      url,
+      method,
+      data,
+      params,
+      responseType: 'blob',
+      skipGlobalErrorMessage: true,
+    } as ExportRequestConfig)
+
+    return downloadExportResponse(response, 'download')
+  } finally {
+    finishLoading(loading)
+  }
 }
 
 /** 发送 POST 请求并返回可逐块读取的原始响应。 */
-export function postStream(base: string, path: string, data?: unknown) {
+export function postStream(base: string, path: string, data?: unknown, config?: StreamRequestConfig): Promise<Response> {
   const { auth, user } = useStore()
   const headers: Record<string, string> = { 'Content-Type': 'application/json' }
   if (auth.token) {
@@ -269,6 +269,7 @@ export function postStream(base: string, path: string, data?: unknown) {
     method: 'POST',
     headers,
     body: data === undefined ? undefined : JSON.stringify(data),
+    signal: config?.signal,
   })
 }
 
diff --git a/ui/src/api/admin/workspace/application/application.ts b/ui/src/api/admin/workspace/application/application.ts
index 99e590a5e01..4112bad256f 100644
--- a/ui/src/api/admin/workspace/application/application.ts
+++ b/ui/src/api/admin/workspace/application/application.ts
@@ -2,6 +2,7 @@ import { del, get, getExportFile, post, postStream, put } from '../../core/reque
 import type { ParamsPage, ResponsePage } from '../../core/types'
 import type { ApplicationDetail, ApplicationFormPayload, Dict, PromptGeneratePayload } from '@/api/types'
 import { getWorkspaceId } from '@/utils/resource-context'
+import { ADMIN_API_BASE_PATH } from '@/api/constants'
 
 const getPrefix = () => {
   const workspaceId = getWorkspaceId()
@@ -74,7 +75,7 @@ const putApplicationPublish = (applicationId: string) => {
 
 /** 使用指定模型流式生成或优化系统提示词。 */
 const postPromptGenerate = (applicationId: string, modelId: string, payload: PromptGeneratePayload, signal?: AbortSignal) => {
-  return postStream(`${getPrefix()}/${applicationId}/model/${modelId}/prompt_generate`, payload, { signal })
+  return postStream(ADMIN_API_BASE_PATH, `${getPrefix()}/${applicationId}/model/${modelId}/prompt_generate`, payload, { signal })
 }
 
 export default {
diff --git a/ui/src/api/chat/core/request.ts b/ui/src/api/chat/core/request.ts
index b9728d770bb..5f6a9229892 100644
--- a/ui/src/api/chat/core/request.ts
+++ b/ui/src/api/chat/core/request.ts
@@ -9,9 +9,9 @@ import { useStore } from '@/stores'
 import type { ApiResponse, LoadingTarget } from './types'
 import type { Dict } from '@/api/types'
 import { MsgError } from '@/utils/message'
+import { CHAT_API_BASE_PATH } from '@/api/constants'
 
 const DEFAULT_TIMEOUT = 30 * 60 * 1_000 // 30 minutes
-const CHAT_BASE_PATH = window.MaxKB?.chatPrefix || import.meta.env.VITE_BASE_PATH || '/chat/'
 
 function setRequestHeaders(config: InternalAxiosRequestConfig) {
   const { auth, user } = useStore()
@@ -64,7 +64,7 @@ async function getResponseErrorMessage(error: unknown) {
 }
 
 export const request = axios.create({
-  baseURL: `${CHAT_BASE_PATH.replace(/\/+$/, '')}/api`,
+  baseURL: CHAT_API_BASE_PATH,
   timeout: DEFAULT_TIMEOUT,
   withCredentials: false,
 })
diff --git a/ui/src/api/constants.ts b/ui/src/api/constants.ts
new file mode 100644
index 00000000000..08c27516a2a
--- /dev/null
+++ b/ui/src/api/constants.ts
@@ -0,0 +1,6 @@
+/** Admin 与 Chat 的 API 部署路径配置。 */
+const trimTrailingSlash = (value: string) => value.replace(/\/+$/, '')
+
+export const ADMIN_API_BASE_PATH = trimTrailingSlash(window.MaxKB?.prefix || import.meta.env.VITE_BASE_PATH || '/admin/') + '/api'
+
+export const CHAT_API_BASE_PATH = trimTrailingSlash(window.MaxKB?.chatPrefix || import.meta.env.VITE_BASE_PATH || '/chat/') + '/api'
diff --git a/ui/src/components/conversation/api/index.ts b/ui/src/components/conversation/api/index.ts
index 6d1df02cb67..7560c8a7d6c 100644
--- a/ui/src/components/conversation/api/index.ts
+++ b/ui/src/components/conversation/api/index.ts
@@ -21,13 +21,7 @@ import {
 } from '@/api/chat/core/request'
 import { useStore } from '@/stores'
 import { getWorkspaceId } from '@/utils/resource-context'
-
-const trimTrailingSlash = (value: string) => value.replace(/\/+$/, '')
-const adminApiBase =
-  trimTrailingSlash(window.MaxKB?.prefix || import.meta.env.VITE_BASE_PATH || '/admin/') + '/api'
-
-const chatApiBase =
-  trimTrailingSlash(window.MaxKB?.chatPrefix || import.meta.env.VITE_BASE_PATH || '/chat/') + '/api'
+import { ADMIN_API_BASE_PATH as adminApiBase, CHAT_API_BASE_PATH as chatApiBase } from '@/api/constants'
 
 /** 发送流式 POST 请求，返回原始 `Response` 供 SSE 读取。 */
 function postStream(base: string, path: string, data?: unknown) {