diff --git a/src/app/chat/__tests__/chat-area.helpers.test.ts b/src/app/chat/__tests__/chat-area.helpers.test.ts
index 584c8037..bcc56a9f 100644
--- a/src/app/chat/__tests__/chat-area.helpers.test.ts
+++ b/src/app/chat/__tests__/chat-area.helpers.test.ts
@@ -5,7 +5,7 @@ import type { UiMessage } from "@/data/dto/chat";
 import {
   buildChatRenderItems,
   createChatMessageKeyResolver,
-} from "../components/chat-area";
+} from "../chat-render-items";
 
 describe("chat area render items", () => {
   it("keeps local message keys stable when history is prepended", () => {
diff --git a/src/app/chat/chat-render-items.ts b/src/app/chat/chat-render-items.ts
new file mode 100644
index 00000000..1edc93ea
--- /dev/null
+++ b/src/app/chat/chat-render-items.ts
@@ -0,0 +1,45 @@
+import type { UiMessage } from "@/data/dto/chat";
+
+export type ChatMessageKeyResolver = (message: UiMessage) => string;
+
+export type ChatRenderItem =
+  | { type: "date"; date: string; key: string }
+  | { type: "msg"; message: UiMessage; key: string };
+
+export function createChatMessageKeyResolver(): ChatMessageKeyResolver {
+  const localMessageKeys = new WeakMap<UiMessage, string>();
+  let nextLocalMessageKey = 0;
+
+  return (message) => {
+    if (message.id && message.id.length > 0) return `msg-${message.id}`;
+
+    const existing = localMessageKeys.get(message);
+    if (existing) return existing;
+
+    nextLocalMessageKey += 1;
+    const next = `local-msg-${nextLocalMessageKey}`;
+    localMessageKeys.set(message, next);
+    return next;
+  };
+}
+
+export function buildChatRenderItems(
+  messages: readonly UiMessage[],
+  getMessageKey: ChatMessageKeyResolver,
+): ChatRenderItem[] {
+  const items: ChatRenderItem[] = [];
+
+  messages.forEach((message, index) => {
+    const messageKey = getMessageKey(message);
+    if (index === 0 || message.date !== messages[index - 1].date) {
+      items.push({
+        type: "date",
+        date: message.date,
+        key: `date-${message.date}-${messageKey}`,
+      });
+    }
+    items.push({ type: "msg", message, key: messageKey });
+  });
+
+  return items;
+}
diff --git a/src/app/chat/components/chat-area.tsx b/src/app/chat/components/chat-area.tsx
index 8cfb0953..2c13d681 100644
--- a/src/app/chat/components/chat-area.tsx
+++ b/src/app/chat/components/chat-area.tsx
@@ -22,6 +22,11 @@ import {
   listenChatScrollSnapshotSave,
   saveChatScrollSnapshot,
 } from "../chat-scroll-session";
+import {
+  buildChatRenderItems,
+  createChatMessageKeyResolver,
+  type ChatMessageKeyResolver,
+} from "../chat-render-items";
 import { AiDisclosureBanner } from "./ai-disclosure-banner";
 import { DateHeader } from "./date-header";
 import { LottieMessageBubble } from "./lottie-message-bubble";
@@ -31,10 +36,6 @@ import styles from "./chat-area.module.css";
 const CHAT_AUTO_SCROLL_BOTTOM_THRESHOLD = 96;
 
 type RestoreState = "idle" | "checking" | "restoring" | "settlingBottom" | "done";
-type ChatMessageKeyResolver = (message: UiMessage) => string;
-type ChatRenderItem =
-  | { type: "date"; date: string; key: string }
-  | { type: "msg"; message: UiMessage; key: string };
 
 export interface ChatAreaProps {
   messages: readonly UiMessage[];
@@ -226,7 +227,7 @@ function startStableScrollTask({
 /** 渲染消息列表（按日期分组插入分隔条） */
 function renderMessagesWithDateHeaders(
   messages: readonly UiMessage[],
-  getMessageKey: (message: UiMessage) => string,
+  getMessageKey: ChatMessageKeyResolver,
   isUnlockingMessage?: boolean,
   unlockingMessageId?: string | null,
   onUnlockPrivateMessage?: (messageId: string) => void,
@@ -258,41 +259,3 @@ function renderMessagesWithDateHeaders(
     ),
   );
 }
-
-export function createChatMessageKeyResolver(): ChatMessageKeyResolver {
-  const localMessageKeys = new WeakMap<UiMessage, string>();
-  let nextLocalMessageKey = 0;
-
-  return (message) => {
-    if (message.id && message.id.length > 0) return `msg-${message.id}`;
-
-    const existing = localMessageKeys.get(message);
-    if (existing) return existing;
-
-    nextLocalMessageKey += 1;
-    const next = `local-msg-${nextLocalMessageKey}`;
-    localMessageKeys.set(message, next);
-    return next;
-  };
-}
-
-export function buildChatRenderItems(
-  messages: readonly UiMessage[],
-  getMessageKey: ChatMessageKeyResolver,
-): ChatRenderItem[] {
-  const items: ChatRenderItem[] = [];
-
-  messages.forEach((message, index) => {
-    const messageKey = getMessageKey(message);
-    if (index === 0 || message.date !== messages[index - 1].date) {
-      items.push({
-        type: "date",
-        date: message.date,
-        key: `date-${message.date}-${messageKey}`,
-      });
-    }
-    items.push({ type: "msg", message, key: messageKey });
-  });
-
-  return items;
-}