diff --git a/src/stores/chat/__tests__/chat-machine.transitions.test.ts b/src/stores/chat/__tests__/chat-machine.transitions.test.ts
index 57bf9bdd..eed2dcd4 100644
--- a/src/stores/chat/__tests__/chat-machine.transitions.test.ts
+++ b/src/stores/chat/__tests__/chat-machine.transitions.test.ts
@@ -164,6 +164,30 @@ describe("chatMachine transitions", () => {
     actor.stop();
   });
 
+  it("ignores repeated user login while an authenticated user session is active", async () => {
+    const actor = createActor(createTestChatMachine()).start();
+
+    actor.send({ type: "ChatUserLogin", token: "token" });
+    await waitFor(actor, (snapshot) =>
+      snapshot.matches({ userSession: "ready" }),
+    );
+
+    actor.send({ type: "ChatSendMessage", content: "keep this message" });
+    await waitFor(
+      actor,
+      (snapshot) => snapshot.context.messages.length === 1,
+    );
+
+    actor.send({ type: "ChatUserLogin", token: "another-token" });
+
+    expect(actor.getSnapshot().matches({ userSession: "ready" })).toBe(true);
+    expect(actor.getSnapshot().context.messages).toMatchObject([
+      { content: "keep this message", isFromAI: false },
+    ]);
+
+    actor.stop();
+  });
+
   it("allows multiple messages to be queued without leaving ready state", async () => {
     const actor = createActor(createTestChatMachine()).start();
 
diff --git a/src/stores/chat/chat-auth-sync.tsx b/src/stores/chat/chat-auth-sync.tsx
index fe81d0cc..fe47e785 100644
--- a/src/stores/chat/chat-auth-sync.tsx
+++ b/src/stores/chat/chat-auth-sync.tsx
@@ -10,7 +10,7 @@
 import { useEffect, useRef } from "react";
 import { usePathname, useRouter } from "next/navigation";
 
-import { AuthStorage } from "@/data/storage/auth/auth_storage";
+import { AuthStorage } from "@/data/storage/auth";
 import { useAuthState } from "@/stores/auth/auth-context";
 import { PROTECTED_ROUTES, ROUTES, type StaticRoute } from "@/router/routes";
 
diff --git a/src/stores/chat/chat-machine.ts b/src/stores/chat/chat-machine.ts
index 86dc79ed..09946577 100644
--- a/src/stores/chat/chat-machine.ts
+++ b/src/stores/chat/chat-machine.ts
@@ -1,17 +1,10 @@
 /**
  * Chat 状态机（XState v5）
  *
- * 鉴权解耦（事件驱动）：
- *   chat 机器不感知鉴权 —— 由 <ChatAuthSync /> 派生 loginStatus
- *   ChatAuthSync 派发登录态生命周期事件：
- *     - `ChatGuestLogin` → 游客会话
- *     - `ChatUserLogin { token }` → 其他登录用户会话
- *     - `ChatLogout` → 正式登录用户登出
- *
  * 登录态流转约束：
  *   - 未登录：可以进入游客登录 / 其他登录。
  *   - 游客登录：只可以升级为其他登录，不响应退出。
- *   - 其他登录：可以退出，不响应游客登录。
+ *   - 其他登录：可以退出，不响应游客登录 / 重复其他登录。
  *
  * 状态结构（parent state 模式）：
  *   - `idle`：屏没挂 / 登出
@@ -363,11 +356,6 @@ export const chatMachine = setup({
           target: "#chat.idle",
           actions: "clearChatSession",
         },
-        ChatUserLogin: {
-          target: "#chat.userSession",
-          reenter: true,
-          actions: "startUserSession",
-        },
         ChatQueuedSendStarted: {
           actions: "markQueuedSendStarted",
         },