diff --git a/web/src/engine/messageIdentity.test.ts b/web/src/engine/messageIdentity.test.ts
new file mode 100644
index 00000000..ac8dbbfe
--- /dev/null
+++ b/web/src/engine/messageIdentity.test.ts
@@ -0,0 +1,48 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  isSameMessage,
+  filterPendingLiveMessages,
+  mergeLiveOverHistory,
+} from './messageIdentity';
+import type { ChatMessage } from '../types/workbench';
+
+const base = (patch: Partial<ChatMessage>): ChatMessage => ({
+  id: 'tmp-1',
+  sessionId: 'sess-1',
+  role: 'user',
+  content: 'hello',
+  timestamp: '10:00',
+  ...patch,
+});
+
+test('isSameMessage: clientTurnId match', () => {
+  const local = base({ id: 'tmp-user', clientTurnId: 'turn-abc' });
+  const server = base({ id: 'msg-101', serverId: 101, clientTurnId: 'turn-abc' });
+  assert.equal(isSameMessage(local, server), true);
+});
+
+test('isSameMessage: serverId match without turn', () => {
+  const local = base({ id: 'ast-123', serverId: 102, role: 'assistant' });
+  const server = base({ id: 'msg-102', serverId: 102, role: 'assistant' });
+  assert.equal(isSameMessage(local, server), true);
+});
+
+test('filterPendingLiveMessages: real temp vs server id', () => {
+  const history = [base({ id: 'msg-101', serverId: 101, clientTurnId: 'turn-abc' })];
+  const live = [
+    base({ id: 'tmp-user', clientTurnId: 'turn-abc' }),
+    base({ id: 'tmp-asst', role: 'assistant', clientTurnId: 'turn-abc', serverId: 102 }),
+  ];
+  const pending = filterPendingLiveMessages(live, history);
+  assert.equal(pending.length, 1);
+  assert.equal(pending[0].role, 'assistant');
+});
+
+test('mergeLiveOverHistory preserves server id from live', () => {
+  const history = base({ id: 'msg-101', serverId: 101, content: 'hello' });
+  const live = base({ id: 'tmp-user', serverId: 101, content: 'hello', status: undefined });
+  const merged = mergeLiveOverHistory(history, live);
+  assert.equal(merged.id, 'msg-101');
+  assert.equal(merged.serverId, 101);
+});
diff --git a/web/src/tests/workflow-chat-chronology.test.ts b/web/src/tests/workflow-chat-chronology.test.ts
index dc307616..d5982502 100644
--- a/web/src/tests/workflow-chat-chronology.test.ts
+++ b/web/src/tests/workflow-chat-chronology.test.ts
@@ -2,6 +2,7 @@ import { test, describe } from 'node:test';
 import assert from 'node:assert/strict';
 import { flattenDayStack } from '../hooks/useVirtualMessages';
 import { ChatDayBucket, ChatMessage } from '../types/workbench';
+import { filterPendingLiveMessages } from '../engine/messageIdentity';
 
 describe('工作流切换与消息展示时序测试套件', () => {
   test('1. 当存在历史 seed 消息且追加新实时消息时，新消息必须严格沉淀在末尾', () => {
@@ -12,8 +13,11 @@ describe('工作流切换与消息展示时序测试套件', () => {
       { id: 'seed-4', sessionId: 'sess-1', role: 'assistant', content: '历史答复2', timestamp: '09:11' },
     ];
 
+    const clientTurnId = 'turn-live-abc';
     const newlySentUserMsg: ChatMessage = {
-      id: 'msg-live-1',
+      id: 'tmp-user-uuid',
+      clientTurnId,
+      clientMessageId: `${clientTurnId}:user`,
       sessionId: 'sess-1',
       role: 'user',
       content: '分析一下测试方案中，有哪些比较难的项目，以及需要特别注意的地方',
@@ -21,46 +25,61 @@ describe('工作流切换与消息展示时序测试套件', () => {
     };
 
     const newlyRepliedAsstMsg: ChatMessage = {
-      id: 'ast-live-2',
+      id: 'tmp-asst-uuid',
+      clientTurnId,
+      clientMessageId: `${clientTurnId}:assistant`,
       sessionId: 'sess-1',
       role: 'assistant',
       content: '针对肌骨超声AI辅助诊断系统的系统验证方案...',
       timestamp: '10:01',
+      serverId: 102,
     };
 
-    const fullLiveMessages: ChatMessage[] = [
-      ...historicalMessages,
-      newlySentUserMsg,
-      newlyRepliedAsstMsg,
-    ];
+    // 切回项目时 live 仅保留进行中/未对账的 temp 消息（历史已由服务端窗口提供）
+    const fullLiveMessages: ChatMessage[] = [newlySentUserMsg, newlyRepliedAsstMsg];
 
-    // 模拟服务端只持久化了新返回的 2 条记录 (原 Bug 触发场景)
+    // 服务端窗口含历史 + 新落库消息（真实 ID 与本地 temp 不同）
     const serverDayStack: ChatDayBucket[] = [
       {
         dayKey: '2026-09-11',
-        count: 2,
-        loadedCount: 2,
+        count: 6,
+        loadedCount: 6,
         truncated: false,
-        firstMessageId: 101,
+        firstMessageId: 97,
         lastMessageId: 102,
         messages: [
-          { ...newlySentUserMsg, serverId: 101 },
-          { ...newlyRepliedAsstMsg, serverId: 102 },
+          ...historicalMessages.map((m, i) => ({
+            ...m,
+            id: `msg-${97 + i}`,
+            serverId: 97 + i,
+          })),
+          {
+            id: 'msg-101',
+            clientTurnId,
+            clientMessageId: `${clientTurnId}:user`,
+            sessionId: 'sess-1',
+            role: 'user' as const,
+            content: newlySentUserMsg.content,
+            timestamp: '10:00',
+            serverId: 101,
+          },
+          {
+            id: 'msg-102',
+            clientTurnId,
+            clientMessageId: `${clientTurnId}:assistant`,
+            sessionId: 'sess-1',
+            role: 'assistant' as const,
+            content: newlyRepliedAsstMsg.content,
+            timestamp: '10:01',
+            serverId: 102,
+          },
         ],
       },
     ];
 
-    // 运用修复后的保序合并算法
     const todayStr = '2026-09-11';
-    const existingMsgIds = new Set<string>();
-    for (const b of serverDayStack) {
-      for (const m of b.messages) {
-        existingMsgIds.add(m.id);
-        if (m.serverId) existingMsgIds.add(`msg-${m.serverId}`);
-      }
-    }
-
-    const pendingLive = fullLiveMessages.filter((m) => !existingMsgIds.has(m.id));
+    const historyMessages = serverDayStack.flatMap((b) => b.messages);
+    const pendingLive = filterPendingLiveMessages(fullLiveMessages, historyMessages);
 
     const result = serverDayStack.map((b) => ({ ...b, messages: [...b.messages] }));
     const todayBucket = result.find((b) => b.dayKey === todayStr)!;
@@ -87,58 +106,49 @@ describe('工作流切换与消息展示时序测试套件', () => {
 
     const flat = flattenDayStack(result);
 
-    // 校验总数
     assert.equal(flat.length, 6);
-    // 校验第 1 条依然是历史第一条，绝对没有被反转
-    assert.equal(flat[0].id, 'seed-1');
-    assert.equal(flat[1].id, 'seed-2');
-    assert.equal(flat[2].id, 'seed-3');
-    assert.equal(flat[3].id, 'seed-4');
-    // 校验最后两条为刚刚发送的用户提问和助手回复，严格在最底部
-    assert.equal(flat[4].id, 'msg-live-1');
-    assert.equal(flat[5].id, 'ast-live-2');
+    assert.equal(pendingLive.length, 0);
+    assert.equal(flat.filter((m) => m.clientTurnId === clientTurnId).length, 2);
+    assert.equal(flat[4].id, 'msg-101');
+    assert.equal(flat[5].id, 'msg-102');
   });
 
-  test('2. 页面刷新后，即使本地 liveMessages 未包含新消息，按时间戳与自增 ID 排序也绝对不倒挂在历史消息前', () => {
-    // 模拟服务端返回完整按时间排布的消息
-    const historicalMessages: ChatMessage[] = [
-      { id: 'm-jigu-1', sessionId: 'sess-jigu-u1', role: 'system', content: '助手就位', timestamp: '09:00', createdAt: '2026-09-11T09:00:00+08:00', serverId: 25217 },
-      { id: 'm-jigu-2', sessionId: 'sess-jigu-u1', role: 'user', content: '用户需求', timestamp: '09:14', createdAt: '2026-09-11T09:14:00+08:00', serverId: 25218 },
+  test('2. 切回项目时相同正文不应因 temp/server id 差异重复展示', () => {
+    const clientTurnId = 'turn-jigu-dup';
+    const liveMessages: ChatMessage[] = [
+      {
+        id: 'tmp-user',
+        clientTurnId,
+        sessionId: 'sess-jigu-u1',
+        role: 'user',
+        content: '分析一下测试方案中...',
+        timestamp: '10:06',
+        serverId: 25227,
+      },
     ];
-
-    const serverRecentMessages: ChatMessage[] = [
-      { id: 'msg-25227', sessionId: 'sess-jigu-u1', role: 'user', content: '分析一下测试方案中...', timestamp: '10:06', createdAt: '2026-09-11T10:06:46+08:00', serverId: 25227 },
-      { id: 'msg-25228', sessionId: 'sess-jigu-u1', role: 'assistant', content: '针对测试方案...', timestamp: '10:07', createdAt: '2026-09-11T10:07:26+08:00', serverId: 25228 },
+    const serverDayStack: ChatDayBucket[] = [
+      {
+        dayKey: '2026-09-11',
+        count: 1,
+        loadedCount: 1,
+        truncated: false,
+        firstMessageId: 25227,
+        lastMessageId: 25227,
+        messages: [
+          {
+            id: 'msg-25227',
+            clientTurnId,
+            sessionId: 'sess-jigu-u1',
+            role: 'user',
+            content: '分析一下测试方案中...',
+            timestamp: '10:06',
+            serverId: 25227,
+          },
+        ],
+      },
     ];
-
-    const allInBucket = [...serverRecentMessages, ...historicalMessages]; // 故意打乱测试排序算法鲁棒性
-
-    const getMessageSortTime = (m: ChatMessage): number => {
-      if (m.createdAt) {
-        const t = new Date(m.createdAt).getTime();
-        if (!isNaN(t)) return t;
-      }
-      if (m.timestamp && m.timestamp.includes(':')) {
-        const [hh, mm] = m.timestamp.split(':').map(Number);
-        if (!isNaN(hh) && !isNaN(mm)) {
-          const d = new Date();
-          d.setHours(hh, mm, 0, 0);
-          return d.getTime();
-        }
-      }
-      return 0;
-    };
-
-    allInBucket.sort((a, b) => {
-      const tA = getMessageSortTime(a);
-      const tB = getMessageSortTime(b);
-      if (tA !== 0 && tB !== 0 && tA !== tB) return tA - tB;
-      return (a.serverId || 0) - (b.serverId || 0);
-    });
-
-    assert.equal(allInBucket[0].id, 'm-jigu-1');
-    assert.equal(allInBucket[1].id, 'm-jigu-2');
-    assert.equal(allInBucket[2].id, 'msg-25227');
-    assert.equal(allInBucket[3].id, 'msg-25228');
+    const history = serverDayStack.flatMap((b) => b.messages);
+    const pending = filterPendingLiveMessages(liveMessages, history);
+    assert.equal(pending.length, 0);
   });
 });