feat: Implement incremental historical event loading and a centralized state synchronization mechanism, including stream reconnection, for the AgentAudit page.

backend/app/services/agent/agents/analysis.py

@@ -574,6 +574,17 @@ Final Answer: {{"findings": [...], "summary": "..."}}"""
                 # 重置空响应计数器
                 self._empty_retry_count = 0
 
+                # 🔥 检查是否是 API 错误（从 BaseAgent.stream_llm_call 返回）
+                if llm_output.startswith("[API_ERROR:"):
+                    # 提取错误类型和消息
+                    match = re.match(r"\[API_ERROR:(\w+)\]\s*(.*)", llm_output)
+                    if match:
+                        error_type = match.group(1)
+                        error_message = match.group(2)
+                        logger.error(f"[{self.name}] Fatal API error: {error_type} - {error_message}")
+                        await self.emit_event("error", f"LLM API 错误 ({error_type}): {error_message}")
+                        break
+
                 # 解析 LLM 响应
                 step = self._parse_llm_response(llm_output)
                 self._steps.append(step)

backend/app/services/agent/agents/base.py

@@ -1033,7 +1033,7 @@ class BaseAgent(ABC):
 
                         # 使用特殊前缀标记 API 错误，让调用方能够识别
                         # 格式：[API_ERROR:error_type] user_message
-                        if error_type in ("rate_limit", "quota_exceeded", "authentication", "connection"):
+                        if error_type in ("rate_limit", "quota_exceeded", "authentication", "connection", "server_error"):
                             accumulated = f"[API_ERROR:{error_type}] {user_message}"
                         elif not accumulated:
                             accumulated = f"[系统错误: {error_msg}] 请重新思考并输出你的决策。"

backend/app/services/agent/agents/orchestrator.py

@@ -331,6 +331,19 @@ Action Input: {{"参数": "值"}}
                             await asyncio.sleep(5)  # 等待 5 秒后重试
                             continue
 
+                        elif error_type == "server_error":
+                            # 服务器错误 (5xx) - 重试
+                            api_retry_count = getattr(self, '_api_retry_count', 0) + 1
+                            self._api_retry_count = api_retry_count
+                            if api_retry_count >= 3:
+                                logger.error(f"[{self.name}] Too many server errors, stopping")
+                                await self.emit_event("error", f"API 服务端错误重试次数过多: {error_message}")
+                                break
+                            logger.warning(f"[{self.name}] Server error, retrying ({api_retry_count}/3)")
+                            await self.emit_event("warning", f"API 服务端繁忙或异常，重试中 ({api_retry_count}/3)")
+                            await asyncio.sleep(10)  # 等待 10 秒后重试（服务端错误通常需要更久恢复）
+                            continue
+
                 # 重置 API 重试计数器（成功获取响应后）
                 self._api_retry_count = 0
 

backend/app/services/agent/agents/recon.py

@@ -509,6 +509,17 @@ Final Answer: [JSON格式的结果]"""
                 # 重置空响应计数器
                 self._empty_retry_count = 0
 
+                # 🔥 检查是否是 API 错误（从 BaseAgent.stream_llm_call 返回）
+                if llm_output.startswith("[API_ERROR:"):
+                    # 提取错误类型和消息
+                    match = re.match(r"\[API_ERROR:(\w+)\]\s*(.*)", llm_output)
+                    if match:
+                        error_type = match.group(1)
+                        error_message = match.group(2)
+                        logger.error(f"[{self.name}] Fatal API error: {error_type} - {error_message}")
+                        await self.emit_event("error", f"LLM API 错误 ({error_type}): {error_message}")
+                        break
+
                 # 解析 LLM 响应
                 step = self._parse_llm_response(llm_output)
                 self._steps.append(step)

backend/app/services/agent/agents/verification.py

@@ -718,6 +718,17 @@ class VerificationAgent(BaseAgent):
                 
                 self._total_tokens += tokens_this_round
 
+                # 🔥 检查是否是 API 错误（从 BaseAgent.stream_llm_call 返回）
+                if llm_output.startswith("[API_ERROR:"):
+                    # 提取错误类型和消息
+                    match = re.match(r"\[API_ERROR:(\w+)\]\s*(.*)", llm_output)
+                    if match:
+                        error_type = match.group(1)
+                        error_message = match.group(2)
+                        logger.error(f"[{self.name}] Fatal API error: {error_type} - {error_message}")
+                        await self.emit_event("error", f"LLM API 错误 ({error_type}): {error_message}")
+                        break
+
                 # 🔥 Handle empty LLM response to prevent loops
                 if not llm_output or not llm_output.strip():
                     logger.warning(f"[{self.name}] Empty LLM response in iteration {self._iteration}")

backend/app/services/llm/adapters/litellm_adapter.py

@@ -251,6 +251,9 @@ class LiteLLMAdapter(BaseLLMAdapter):
         except litellm.exceptions.APIConnectionError as e:
             api_response = self._extract_api_response(e)
             raise LLMError(f"无法连接到 API 服务", self.config.provider, api_response=api_response)
+        except (litellm.exceptions.ServiceUnavailableError, litellm.exceptions.InternalServerError) as e:
+            api_response = self._extract_api_response(e)
+            raise LLMError(f"API 服务暂时不可用 ({type(e).__name__})", self.config.provider, 503, api_response=api_response)
         except litellm.exceptions.APIError as e:
             api_response = self._extract_api_response(e)
             raise LLMError(f"API 错误", self.config.provider, getattr(e, 'status_code', None), api_response=api_response)
@@ -469,6 +472,17 @@ class LiteLLMAdapter(BaseLLMAdapter):
                 "accumulated": accumulated_content,
                 "usage": None,
             }
+        except (litellm.exceptions.ServiceUnavailableError, litellm.exceptions.InternalServerError) as e:
+            # 服务不可用 - 服务器端 5xx 错误
+            logger.error(f"Stream server error ({type(e).__name__}): {e}")
+            yield {
+                "type": "error",
+                "error_type": "server_error", 
+                "error": str(e),
+                "user_message": f"API 服务暂时不可用 ({type(e).__name__})",
+                "accumulated": accumulated_content,
+                "usage": None,
+            }
 
         except Exception as e:
             # 其他错误 - 检查是否是包装的速率限制错误

frontend/src/pages/AgentAudit/index.tsx

@@ -146,23 +146,33 @@ function AgentAuditPageContent() {
   }, [loadAgentTree]);
 
   // 🔥 NEW: 加载历史事件并转换为日志项
-  const loadHistoricalEvents = useCallback(async () => {
+  const loadHistoricalEvents = useCallback(async (isSync = false) => {
     if (!taskId) return 0;
 
-    // 🔥 防止重复加载历史事件
+    // 🔥 只有在非同步模式下才检查是否已加载过（首屏加载）
-    if (hasLoadedHistoricalEventsRef.current) {
+    if (!isSync && hasLoadedHistoricalEventsRef.current) {
       console.log('[AgentAudit] Historical events already loaded, skipping');
       return 0;
     }
+
+    // 如果是首屏加载，标记为已尝试加载
+    if (!isSync) {
       hasLoadedHistoricalEventsRef.current = true;
+    }
 
     try {
-      console.log(`[AgentAudit] Fetching historical events for task ${taskId}...`);
+      const currentSeq = lastEventSequenceRef.current;
-      const events = await getAgentEvents(taskId, { limit: 500 });
+      console.log(`[AgentAudit] Fetching historical events for task ${taskId} (after_sequence=${currentSeq})...`);
+
+      // 🔥 传递当前已知的最后序列号，实现增量加载
+      const events = await getAgentEvents(taskId, {
+        after_sequence: currentSeq,
+        limit: 500
+      });
       console.log(`[AgentAudit] Received ${events.length} events from API`);
 
       if (events.length === 0) {
-        console.log('[AgentAudit] No historical events found');
+        console.log('[AgentAudit] No new historical events found');
         return 0;
       }
 
@@ -629,8 +639,43 @@ function AgentAuditPageContent() {
     disconnectStreamRef.current = disconnectStream;
   }, [disconnectStream]);
 
+  // 🔥 Centralized Sync State Function
+  const syncState = useCallback(async () => {
+    if (!taskId) return;
+
+    console.log('[AgentAudit] Synchronizing state...');
+    try {
+      // 1. 同步任务基本信息、发现项和树结构
+      await Promise.all([loadTask(), loadFindings(), loadAgentTree()]);
+
+      // 2. 增量同步日志完成状态或缺失日志
+      await loadHistoricalEvents(true);
+
+      // 3. 如果连接断开且任务仍在运行，尝试重新连接流
+      if (!isConnected && isRunning) {
+        console.log('[AgentAudit] Stream disconnected while task running, attempting reconnect...');
+        hasConnectedRef.current = false; // 允许重新连接
+        connectStream();
+      }
+    } catch (err) {
+      console.error('[AgentAudit] Failed to sync state:', err);
+    }
+  }, [taskId, loadTask, loadFindings, loadAgentTree, loadHistoricalEvents, isConnected, isRunning, connectStream]);
+
   // ============ Effects ============
 
+  // 🔥 Visibility Change Listener - 同步状态的主要触发器
+  useEffect(() => {
+    const handleVisibilityChange = () => {
+      if (document.visibilityState === 'visible') {
+        syncState();
+      }
+    };
+
+    document.addEventListener('visibilitychange', handleVisibilityChange);
+    return () => document.removeEventListener('visibilitychange', handleVisibilityChange);
+  }, [syncState]);
+
   // Status animation
   useEffect(() => {
     if (!isRunning) return;