diff --git a/src/services/apiClient.ts b/src/services/apiClient.ts
index 9538b1b..bbc312d 100644
--- a/src/services/apiClient.ts
+++ b/src/services/apiClient.ts
@@ -155,6 +155,26 @@ export async function stopDialog(taskId: string): Promise<StopDialogResponse> {
   });
 }
 
+/** 压缩对话响应 */
+export interface CompactDialogResponse {
+  success: boolean;
+  taskId: string;
+  message?: string;
+  error?: string;
+}
+
+/**
+ * 手动压缩对话历史
+ * POST /api/dialog/compact
+ */
+export async function compactDialog(taskId: string): Promise<CompactDialogResponse> {
+  console.log(`[API] 压缩对话: taskId=${taskId}`);
+  return request<CompactDialogResponse>('/api/dialog/compact', {
+    method: 'POST',
+    body: { taskId }
+  });
+}
+
 /**
  * 创建成功的工具结果
  */
diff --git a/src/services/dialogService.ts b/src/services/dialogService.ts
index aad42ec..3f6b6ca 100644
--- a/src/services/dialogService.ts
+++ b/src/services/dialogService.ts
@@ -73,6 +73,8 @@ export interface DialogCallbacks {
   onError?: (message: string) => void;
   /** 通知消息 */
   onNotification?: (message: string) => void;
+  /** 上下文使用量更新 */
+  onContextUsage?: (data: { currentTokens: number; maxTokens: number; percentage: number }) => void;
 }
 
 /**
@@ -553,6 +555,12 @@ export class DialogSession {
       onComplete: (data) => {
         this.isActive = false;
         this.finalizeTextSegment();
+
+        // 追踪 AI 消息（用于后端重启后恢复）
+        if (this.accumulatedText) {
+          historyManager.trackAiMessage(this.accumulatedText);
+        }
+
         // 发送所有段落
         callbacks.onComplete?.(this.segments);
       },
@@ -639,6 +647,11 @@ export class DialogSession {
         await historyManager.saveCompactedData(data.compactedData);
       },
 
+      onContextUsage: (data) => {
+        console.log('[DialogSession] onContextUsage:', data.currentTokens, '/', data.maxTokens);
+        callbacks.onContextUsage?.(data);
+      },
+
       onOpen: () => {
         console.log('[DialogSession] SSE 连接已建立');
       },
diff --git a/src/services/sseHandler.ts b/src/services/sseHandler.ts
index 081ff32..d2c94bf 100644
--- a/src/services/sseHandler.ts
+++ b/src/services/sseHandler.ts
@@ -27,7 +27,8 @@ import type {
   AgentStartEvent,
   AgentProgressEvent,
   AgentCompleteEvent,
-  AgentErrorEvent
+  AgentErrorEvent,
+  ContextUsageEvent
 } from '../types/api';
 import type { MemoryCompactedEvent } from '../types/memory';
 
@@ -71,6 +72,8 @@ export interface SSECallbacks {
   onAgentError?: (data: AgentErrorEvent) => void;
   /** 记忆压缩完成 */
   onMemoryCompacted?: (data: MemoryCompactedEvent) => void;
+  /** 上下文使用量更新 */
+  onContextUsage?: (data: ContextUsageEvent) => void;
   /** 连接打开 */
   onOpen?: () => void;
   /** 连接关闭 */
@@ -325,6 +328,9 @@ function dispatchEvent(
     case 'memory_compacted':
       callbacks.onMemoryCompacted?.(data as MemoryCompactedEvent);
       break;
+    case 'context_usage':
+      callbacks.onContextUsage?.(data as ContextUsageEvent);
+      break;
     default:
       console.log(`[SSE] 未知事件类型: ${eventType}`, data);
   }
diff --git a/src/utils/messageHandler.ts b/src/utils/messageHandler.ts
index ead218a..177b75a 100644
--- a/src/utils/messageHandler.ts
+++ b/src/utils/messageHandler.ts
@@ -27,6 +27,9 @@ let useBackendService = true;
 /** 当前对话会话 */
 let currentSession: DialogSession | null = null;
 
+/** 最后一个活跃的 taskId（用于压缩等操作） */
+let lastTaskId: string | null = null;
+
 /** 待执行的计划（Plan 模式确认后自动执行） */
 let pendingPlanExecution: {
   panel: vscode.WebviewPanel;
@@ -128,6 +131,8 @@ async function handleUserMessageWithBackend(
   // 创建或复用会话
   if (!currentSession || !currentSession.active) {
     currentSession = dialogManager.createSession(extensionPath, reuseTaskId);
+    // 保存 taskId 用于后续操作（如压缩）
+    lastTaskId = currentSession.getTaskId();
     if (reuseTaskId) {
       console.log('[MessageHandler] 复用 taskId 创建会话:', reuseTaskId);
     }
@@ -253,6 +258,16 @@ async function handleUserMessageWithBackend(
       onNotification: (message) => {
         vscode.window.showInformationMessage(message);
       },
+
+      onContextUsage: (data) => {
+        // 发送上下文使用量到 WebView
+        panel.webview.postMessage({
+          command: 'contextUsage',
+          currentTokens: data.currentTokens,
+          maxTokens: data.maxTokens,
+          percentage: data.percentage
+        });
+      },
     }, mode);
   });
 }
@@ -310,7 +325,15 @@ export async function abortCurrentDialog(): Promise<void> {
  * 获取当前会话的 taskId
  */
 export function getCurrentTaskId(): string | null {
-  return currentSession?.getTaskId() || null;
+  return currentSession?.getTaskId() || lastTaskId;
+}
+
+/**
+ * 设置最后的 taskId（加载历史会话时调用）
+ */
+export function setLastTaskId(taskId: string): void {
+  lastTaskId = taskId;
+  console.log('[MessageHandler] 设置 lastTaskId:', taskId);
 }
 
 /**