diff --git a/static/src/app/lifecycle.ts b/static/src/app/lifecycle.ts
index b72378e..60f0818 100644
--- a/static/src/app/lifecycle.ts
+++ b/static/src/app/lifecycle.ts
@@ -23,6 +23,7 @@ export function created() {
 
 export async function mounted() {
     debugLog('Vue应用已挂载');
+    console.log('[DEBUG_SYSTEM][boot] 前端调试版本已加载 2026-04-05');
     if (window.ensureCsrfToken) {
         window.ensureCsrfToken().catch((err) => {
             console.warn('CSRF token 初始化失败:', err);
diff --git a/static/src/app/methods/history.ts b/static/src/app/methods/history.ts
index eb82300..16a113e 100644
--- a/static/src/app/methods/history.ts
+++ b/static/src/app/methods/history.ts
@@ -1,6 +1,16 @@
 // @ts-nocheck
 import { debugLog } from './common';
 
+const SUB_AGENT_DONE_PREFIX_RE = /^(?:✅\s*)?子智能体\s*#?\s*(\d+)\s*任务摘要[:：]/;
+
+function parseSubAgentDoneLabel(rawContent: any): string | null {
+    const content = (rawContent || '').toString().trim();
+    if (!content) return null;
+    const match = content.match(SUB_AGENT_DONE_PREFIX_RE);
+    if (!match || !/已完成/.test(content)) return null;
+    return `子智能体${match[1]} 任务完成`;
+}
+
 export const historyMethods = {
     // ==========================================
     // 关键功能：获取并显示历史对话内容
@@ -315,6 +325,41 @@ export const historyMethods = {
                     this.messages.push(currentAssistantMessage);
                     currentAssistantMessage = null;
                 }
+                if (message.role === 'system') {
+                    const rawContent = message.content || '';
+                    const label = parseSubAgentDoneLabel(rawContent);
+                    console.log('[DEBUG_SYSTEM][history] 命中 role=system 历史消息', {
+                        rawContent,
+                        matchedSubAgentDone: !!label
+                    });
+                    if (label) {
+                        // 历史中的 system 通知转换为 assistant system action，避免被 role=system 过滤掉
+                        this.messages.push({
+                            role: 'assistant',
+                            actions: [
+                                {
+                                    id: `history-system-${Date.now()}-${Math.random()}`,
+                                    type: 'system',
+                                    content: label,
+                                    variant: 'sub_agent_done',
+                                    streaming: false,
+                                    timestamp: Date.now()
+                                }
+                            ],
+                            streamingThinking: '',
+                            streamingText: '',
+                            currentStreamingType: null,
+                            activeThinkingId: null,
+                            awaitingFirstContent: false,
+                            generatingLabel: ''
+                        });
+                    } else {
+                        console.log('[DEBUG_SYSTEM][history] role=system 被历史加载拦截（非子智能体完成）', {
+                            rawContent
+                        });
+                    }
+                    return;
+                }
 
                 debugLog('处理其他类型消息:', message.role);
                 this.messages.push({
diff --git a/static/src/app/methods/taskPolling.ts b/static/src/app/methods/taskPolling.ts
index de7f713..48bcbe3 100644
--- a/static/src/app/methods/taskPolling.ts
+++ b/static/src/app/methods/taskPolling.ts
@@ -17,6 +17,17 @@ export const taskPollingMethods = {
         const eventType = event.type;
         const eventData = event.data || {};
         const eventIdx = event.idx;
+        if (
+            eventType === 'system_message' ||
+            eventType === 'sub_agent_waiting' ||
+            (eventType === 'user_message' && eventData?.sub_agent_notice)
+        ) {
+            console.log('[DEBUG_SYSTEM][event] 捕获关键事件', {
+                eventType,
+                eventIdx,
+                eventData
+            });
+        }
 
         // 事件去重检查
         if (typeof eventIdx === 'number') {
@@ -145,6 +156,10 @@ export const taskPollingMethods = {
                 this.handleUserMessage(eventData, eventIdx);
                 break;
 
+            case 'system_message':
+                this.handleSystemMessage(eventData, eventIdx);
+                break;
+
             default:
                 debugLog(`[TaskPolling] 未知事件类型: ${eventType}`);
         }
@@ -767,6 +782,20 @@ export const taskPollingMethods = {
         this.conditionalScrollToBottom();
     },
 
+    handleSystemMessage(data: any) {
+        const content = (data?.content || data?.message || '').trim();
+        console.log('[DEBUG_SYSTEM][polling] 收到 system_message 事件', {
+            raw: data,
+            normalizedContent: content,
+            currentConversationId: this.currentConversationId
+        });
+        if (!content) {
+            console.log('[DEBUG_SYSTEM][polling] system_message 内容为空，跳过');
+            return;
+        }
+        this.appendSystemAction(content);
+    },
+
     handleTaskError(data: any) {
         const shouldRetry = Boolean(data?.retry);
         if (shouldRetry) {
diff --git a/static/src/app/methods/ui.ts b/static/src/app/methods/ui.ts
index ed8e3a8..05592ff 100644
--- a/static/src/app/methods/ui.ts
+++ b/static/src/app/methods/ui.ts
@@ -16,6 +16,30 @@ import {
 } from '../../composables/usePanelResize';
 import { debugLog } from './common';
 
+const SUB_AGENT_DONE_PREFIX_RE = /^(?:✅\s*)?子智能体\s*#?\s*(\d+)\s*任务摘要[:：]/;
+
+function parseSubAgentDoneLabel(rawContent: any): string | null {
+    const content = (rawContent || '').toString().trim();
+    if (!content) {
+        console.log('[DEBUG_SYSTEM][ui] parseSubAgentDoneLabel: 空内容');
+        return null;
+    }
+    const match = content.match(SUB_AGENT_DONE_PREFIX_RE);
+    const isCompleted = /已完成/.test(content);
+    console.log('[DEBUG_SYSTEM][ui] parseSubAgentDoneLabel', {
+        content,
+        regex: SUB_AGENT_DONE_PREFIX_RE.toString(),
+        matched: !!match,
+        matchAgentId: match?.[1],
+        isCompleted
+    });
+    if (!match || !isCompleted) {
+        return null;
+    }
+    const agentId = match[1];
+    return `子智能体${agentId} 任务完成`;
+}
+
 export const uiMethods = {
     ensureScrollListener() {
         if (this._scrollListenerReady) {
@@ -759,10 +783,18 @@ export const uiMethods = {
     },
 
     addSystemMessage(content) {
-        if (this.hideSystemMessages) {
+        console.log('[DEBUG_SYSTEM][ui] addSystemMessage 入参', { content });
+        const subAgentDoneLabel = parseSubAgentDoneLabel(content);
+        if (!subAgentDoneLabel) {
+            // 其他 system 消息全部隐藏，且不进入渲染链路，避免出现空白块
+            console.log('[DEBUG_SYSTEM][ui] addSystemMessage 被拦截（非子智能体完成）', { content });
             return;
         }
-        this.chatAddSystemMessage(content);
+        console.log('[DEBUG_SYSTEM][ui] addSystemMessage 通过，写入 action', {
+            original: content,
+            normalizedLabel: subAgentDoneLabel
+        });
+        this.chatAddSystemMessage(subAgentDoneLabel, { variant: 'sub_agent_done' });
         this.$forceUpdate();
         this.conditionalScrollToBottom();
     },
diff --git a/static/src/components/chat/ChatArea.vue b/static/src/components/chat/ChatArea.vue
index ae5cab6..b07aefb 100644
--- a/static/src/components/chat/ChatArea.vue
+++ b/static/src/components/chat/ChatArea.vue
@@ -1,7 +1,15 @@
 <template>
   <div class="messages-area" ref="rootEl">
     <div class="messages-flow">
-      <div v-for="(msg, index) in filteredMessages" :key="index" class="message-block">
+      <div
+        v-for="(msg, index) in filteredMessages"
+        :key="index"
+        class="message-block"
+        :class="{
+          'message-block--sub-agent-notice': isSubAgentNoticeOnlyMessage(msg),
+          'message-block--before-sub-agent-notice': isFollowedBySubAgentNotice(index)
+        }"
+      >
         <div v-if="msg.role === 'user'" class="user-message">
           <div class="message-header icon-label">
             <span class="icon icon-sm" :style="iconStyleSafe('user')" aria-hidden="true"></span>
@@ -24,7 +32,7 @@
         <div v-else-if="msg.role === 'assistant'" class="assistant-message">
           <!-- 在 assistant 消息前显示 AI Assistant 头部 -->
           <!-- 只有当前一条消息是 user 且当前消息有内容时才显示 -->
-          <div v-if="index > 0 && filteredMessages[index - 1].role === 'user' && (msg.actions?.length > 0 || msg.awaitingFirstContent)" class="message-header icon-label">
+          <div v-if="index > 0 && filteredMessages[index - 1].role === 'user' && (hasRenderableAssistantActions(msg.actions || []) || msg.awaitingFirstContent)" class="message-header icon-label">
             <span class="icon icon-sm" :style="iconStyleSafe('bot')" aria-hidden="true"></span>
             <span>{{ aiAssistantName }}</span>
             <span v-if="assistantWorkLabel(index)" class="assistant-work-status">{{ assistantWorkLabel(index) }}</span>
@@ -52,6 +60,7 @@
           </div>
           <template v-if="blockDisplayMode === 'minimal'">
             <MinimalBlocks
+              v-if="hasRenderableAssistantActions(msg.actions || [])"
               :actions="msg.actions || []"
               :conversation-running="streamingMessage"
               :is-latest-message="index === latestMessageIndex"
@@ -87,7 +96,7 @@
                 :format-search-domains="formatSearchDomains"
               />
               <div
-                v-else
+                v-else-if="isActionVisible(group.action)"
                 class="action-item"
                 :key="group.action?.id || `${index}-${group.actionIndex}`"
                 :class="{
@@ -139,10 +148,11 @@
                   </div>
                 </div>
 
-                <div v-else-if="group.action?.type === 'system'" class="system-action">
-                  <div class="system-action-content">
-                    {{ group.action.content }}
-                  </div>
+                <div
+                  v-else-if="group.action?.type === 'system' && getSubAgentSystemNoticeLabel(group.action)"
+                  class="sub-agent-system-summary-line"
+                >
+                  {{ getSubAgentSystemNoticeLabel(group.action) }}
                 </div>
 
                 <div
@@ -224,6 +234,7 @@
           <template v-else>
             <div
               v-for="(action, actionIndex) in msg.actions || []"
+              v-if="isActionVisible(action)"
               :key="action.id || `${index}-${actionIndex}`"
               class="action-item"
               :class="{
@@ -274,10 +285,11 @@
                 </div>
               </div>
 
-              <div v-else-if="action.type === 'system'" class="system-action">
-                <div class="system-action-content">
-                  {{ action.content }}
-                </div>
+              <div
+                v-else-if="action.type === 'system' && getSubAgentSystemNoticeLabel(action)"
+                class="sub-agent-system-summary-line"
+              >
+                {{ getSubAgentSystemNoticeLabel(action) }}
               </div>
 
               <div
@@ -423,12 +435,25 @@ const userName = computed(() => {
   }
   return personalization.form.user_name || '用户';
 });
-const filteredMessages = computed(() =>
-  (props.messages || []).filter(m => !(m && m.metadata && m.metadata.system_injected_image) && m.role !== 'system')
-);
+const filteredMessages = computed(() => {
+  const source = props.messages || [];
+  const droppedRoleSystem = source.filter(m => m && m.role === 'system');
+  if (droppedRoleSystem.length > 0) {
+    console.log('[DEBUG_SYSTEM][render] filteredMessages 过滤了 role=system 消息', {
+      count: droppedRoleSystem.length,
+      samples: droppedRoleSystem.slice(0, 3)
+    });
+  }
+  return source.filter(m => !(m && m.metadata && m.metadata.system_injected_image) && m.role !== 'system');
+});
 const latestMessageIndex = computed(() => filteredMessages.value.length - 1);
+const SUB_AGENT_DONE_LABEL_RE = /^子智能体\d+\s*任务完成$/;
+const SUB_AGENT_DONE_PREFIX_RE = /^(?:✅\s*)?子智能体\s*#?\s*(\d+)\s*任务摘要[:：]/;
+const RENDERABLE_ACTION_TYPES = new Set(['thinking', 'text', 'tool', 'append', 'append_payload', 'system']);
 const nowMs = ref(Date.now());
 let timerHandle: number | null = null;
+const debugLoggedSystemActionKeys = new Set<string>();
+const debugLoggedUnknownActionKeys = new Set<string>();
 
 const DEFAULT_GENERATING_TEXT = '生成中…';
 const rootEl = ref<HTMLElement | null>(null);
@@ -486,6 +511,88 @@ function formatDurationMs(durationMs: number): string {
   return `${String(minutes).padStart(2, '0')}:${String(seconds).padStart(2, '0')}`;
 }
 
+function getSubAgentSystemNoticeLabel(action: any): string | null {
+  if (!action || action.type !== 'system') {
+    return null;
+  }
+  const content = typeof action.content === 'string' ? action.content.trim() : '';
+  const key = action?.id || `no-id-${content.slice(0, 32)}`;
+  if (!content) {
+    if (!debugLoggedSystemActionKeys.has(`${key}-empty`)) {
+      console.log('[DEBUG_SYSTEM][render] system action 内容为空', { action });
+      debugLoggedSystemActionKeys.add(`${key}-empty`);
+    }
+    return null;
+  }
+  if (action.variant === 'sub_agent_done' && SUB_AGENT_DONE_LABEL_RE.test(content)) {
+    if (!debugLoggedSystemActionKeys.has(`${key}-variant-pass`)) {
+      console.log('[DEBUG_SYSTEM][render] 命中 variant 渲染', { action, label: content });
+      debugLoggedSystemActionKeys.add(`${key}-variant-pass`);
+    }
+    return content;
+  }
+  const m = content.match(SUB_AGENT_DONE_PREFIX_RE);
+  if (m && /已完成/.test(content)) {
+    if (!debugLoggedSystemActionKeys.has(`${key}-regex-pass`)) {
+      console.log('[DEBUG_SYSTEM][render] 命中 regex 渲染', { action, normalized: `子智能体${m[1]} 任务完成` });
+      debugLoggedSystemActionKeys.add(`${key}-regex-pass`);
+    }
+    return `子智能体${m[1]} 任务完成`;
+  }
+  if (!debugLoggedSystemActionKeys.has(`${key}-blocked`)) {
+    console.log('[DEBUG_SYSTEM][render] system action 被渲染层拦截', {
+      action,
+      regex: SUB_AGENT_DONE_PREFIX_RE.toString(),
+      completed: /已完成/.test(content)
+    });
+    debugLoggedSystemActionKeys.add(`${key}-blocked`);
+  }
+  return null;
+}
+
+function isActionVisible(action: any): boolean {
+  if (!action) {
+    return false;
+  }
+  const actionType = action.type;
+  if (!RENDERABLE_ACTION_TYPES.has(actionType)) {
+    const key = action?.id || `unknown-${actionType || 'none'}`;
+    if (!debugLoggedUnknownActionKeys.has(key)) {
+      console.log('[DEBUG_SYSTEM][render] 未知 action.type，已跳过渲染', {
+        actionType,
+        action
+      });
+      debugLoggedUnknownActionKeys.add(key);
+    }
+    return false;
+  }
+  if (action.type !== 'system') {
+    return true;
+  }
+  return !!getSubAgentSystemNoticeLabel(action);
+}
+
+function hasRenderableAssistantActions(actions: any[] = []): boolean {
+  return (actions || []).some((action) => isActionVisible(action));
+}
+
+function isSubAgentNoticeOnlyMessage(msg: any): boolean {
+  if (!msg || msg.role !== 'assistant') {
+    return false;
+  }
+  const visibleActions = (msg.actions || []).filter((action: any) => isActionVisible(action));
+  if (visibleActions.length !== 1) {
+    return false;
+  }
+  const onlyAction = visibleActions[0];
+  return onlyAction?.type === 'system' && !!getSubAgentSystemNoticeLabel(onlyAction);
+}
+
+function isFollowedBySubAgentNotice(index: number): boolean {
+  const next = filteredMessages.value[index + 1];
+  return !!next && isSubAgentNoticeOnlyMessage(next);
+}
+
 function assistantWorkLabel(index: number): string {
   if (index <= 0) {
     return '';
diff --git a/static/src/components/chat/MinimalBlocks.vue b/static/src/components/chat/MinimalBlocks.vue
index 1805416..5faddd0 100644
--- a/static/src/components/chat/MinimalBlocks.vue
+++ b/static/src/components/chat/MinimalBlocks.vue
@@ -85,6 +85,19 @@
           <div v-else v-html="renderMarkdown(group.content || '', false)"></div>
         </div>
       </div>
+      <div v-else-if="group.type === 'system'" class="summary-group sub-agent-system-group">
+        <div class="summary-line-text sub-agent-system-summary-line">
+          <div class="summary-content-wrapper">
+            <span class="summary-preview">{{ group.content || '' }}</span>
+          </div>
+          <div class="summary-status-icon">
+            <svg class="check-icon" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+              <circle cx="12" cy="12" r="10" />
+              <polyline points="7.5 12 10.5 15 16.5 9" />
+            </svg>
+          </div>
+        </div>
+      </div>
     </template>
   </div>
 </template>
@@ -118,7 +131,7 @@ interface Step {
 }
 
 interface BlockGroup {
-  type: 'summary' | 'text';
+  type: 'summary' | 'text' | 'system';
   id: string;
   actions?: Action[];
   content?: string;
@@ -204,7 +217,7 @@ const blockGroups = computed(() => {
   props.actions.forEach((action, idx) => {
     if (action.type === 'thinking' || action.type === 'tool') {
       currentGroup.push(action);
-    } else if (action.type === 'text') {
+    } else if (action.type === 'text' || action.type === 'system') {
       // 先保存当前的 thinking/tool 组
       if (currentGroup.length > 0) {
         // 使用第一个 action 的 id 作为 group id，保证稳定性
@@ -217,13 +230,26 @@ const blockGroups = computed(() => {
         groupIndex++;
         currentGroup = [];
       }
-      // 添加 text 组
-      groups.push({
-        type: 'text',
-        id: `text-${idx}`,
-        content: action.content,
-        streaming: action.streaming
-      });
+      if (action.type === 'text') {
+        const text = typeof action.content === 'string' ? action.content : '';
+        if (!text.trim()) {
+          return;
+        }
+        // 添加 text 组
+        groups.push({
+          type: 'text',
+          id: `text-${idx}`,
+          content: text,
+          streaming: action.streaming
+        });
+      } else {
+        // 添加 system 组（用于子智能体完成通知，保持顺序）
+        groups.push({
+          type: 'system',
+          id: `system-${idx}`,
+          content: action.content
+        });
+      }
     }
   });
 
@@ -494,6 +520,18 @@ watch(() => props.actions, () => {
   margin: 16px 0;
 }
 
+.sub-agent-system-group {
+  margin: 0;
+}
+
+.sub-agent-system-group .sub-agent-system-summary-line {
+  cursor: default;
+}
+
+.sub-agent-system-group .sub-agent-system-summary-line:hover {
+  background-color: transparent;
+}
+
 /* 摘要行（只有文字） */
 .summary-line-text {
   display: grid;
diff --git a/static/src/stores/chat.ts b/static/src/stores/chat.ts
index 65254a5..4afa71c 100644
--- a/static/src/stores/chat.ts
+++ b/static/src/stores/chat.ts
@@ -289,15 +289,25 @@ export const useChatStore = defineStore('chat', {
       msg.streamingText = '';
       msg.currentStreamingType = null;
     },
-    addSystemMessage(content: string) {
+    addSystemMessage(content: string, meta: any = null) {
       const msg = this.ensureAssistantMessage();
       clearAwaitingFirstContent(msg);
+      console.log('[DEBUG_SYSTEM][store] addSystemMessage 写入 actions', {
+        content,
+        meta,
+        currentMessageIndex: this.currentMessageIndex,
+        actionsBefore: Array.isArray(msg?.actions) ? msg.actions.length : -1
+      });
       msg.actions.push({
         id: randomId('system'),
         type: 'system',
         content,
+        variant: meta?.variant || null,
         timestamp: Date.now()
       });
+      console.log('[DEBUG_SYSTEM][store] addSystemMessage 写入完成', {
+        actionsAfter: Array.isArray(msg?.actions) ? msg.actions.length : -1
+      });
     },
     getActiveThinkingAction(msg: any) {
       if (!msg || !Array.isArray(msg.actions)) {
diff --git a/static/src/styles/components/chat/_chat-area.scss b/static/src/styles/components/chat/_chat-area.scss
index fc82856..719e7e6 100644
--- a/static/src/styles/components/chat/_chat-area.scss
+++ b/static/src/styles/components/chat/_chat-area.scss
@@ -363,6 +363,26 @@
     margin-bottom: 24px;
 }
 
+.message-block.message-block--sub-agent-notice {
+    margin-bottom: 8px;
+}
+
+.message-block.message-block--before-sub-agent-notice {
+    margin-bottom: 8px;
+}
+
+.message-block.message-block--before-sub-agent-notice .minimal-blocks-container {
+    margin-bottom: 8px;
+}
+
+.message-block.message-block--before-sub-agent-notice .minimal-blocks-container > :last-child {
+    margin-bottom: 0;
+}
+
+.message-block.message-block--sub-agent-notice .minimal-blocks-container {
+    margin: 0;
+}
+
 .user-message {
     display: flex;
     flex-direction: column;
@@ -937,6 +957,14 @@ body[data-theme='dark'] .more-icon {
     gap: 8px;
 }
 
+.sub-agent-system-summary-line {
+    padding: 0 20px 0 15px;
+    margin: 0;
+    font-size: 15px;
+    line-height: 1.7;
+    color: var(--claude-text-secondary);
+}
+
 .append-block,
 .append-placeholder {
     margin: 12px 0;