diff --git a/langgraph/src/components/MessageBubble.tsx b/langgraph/src/components/MessageBubble.tsx
index 17b9e18..6d8fb65 100644
--- a/langgraph/src/components/MessageBubble.tsx
+++ b/langgraph/src/components/MessageBubble.tsx
@@ -148,15 +148,40 @@ function CodeBlock({
   );
 }
 
+const CONCLUSION_KEYWORDS = /总结|结论|建议|综上|总体|总的来说|核心|要点|小结/;
+const FILLER_PATTERN = /^(根据|针对|您好|你好|好的|感谢|当然|如您所述|以下是|下面是)/;
+
 function extractSummary(text: string): string {
+  const lines = text.split("\n").map((l) => l.trim()).filter(Boolean);
+
+  // 1. 优先：含总结关键词的段落首句
+  for (const line of lines) {
+    if (CONCLUSION_KEYWORDS.test(line) && line.length > 8 && !line.startsWith("#")) {
+      return line.replace(/^[*_#>\s-]+/, "").slice(0, 120);
+    }
+  }
+
+  // 2. 次优先：Markdown 标题（## / ###）之后的第一个非空行
+  for (let i = 0; i < lines.length; i++) {
+    if (/^#{2,3}\s/.test(lines[i]) && lines[i + 1]) {
+      const next = lines[i + 1].replace(/^[*_>\s-]+/, "");
+      if (next.length > 8) return next.slice(0, 120);
+    }
+  }
+
+  // 3. Fallback：跳过开场白，取第一个有实质内容的句子
   const sentences = text.split(/(?<=[.。!！?？])\s+/);
+  const meaningful = sentences.find((s) => s.length > 10 && !FILLER_PATTERN.test(s.trim()));
+  if (meaningful) return meaningful.trim().slice(0, 120);
+
+  // 4. 最终 fallback
   return sentences.slice(0, 2).join(" ").trim();
 }
 
 export default function MessageBubble({ content }: MessageBubbleProps) {
   const [summaryExpanded, setSummaryExpanded] = useState(false);
   const contentLines = content.split("\n").length;
-  const isLong = contentLines > 20;
+  const isLong = contentLines > 25 || content.length > 800;
   const summary = isLong ? extractSummary(content) : null;
 
   return (
@@ -166,7 +191,7 @@ export default function MessageBubble({ content }: MessageBubbleProps) {
           <p className="text-xs text-muted-foreground leading-relaxed line-clamp-2">{summary}…</p>
           <button
             type="button"
-            onClick={() => setSummaryExpanded(true)}
+            onClick={() => setSummaryExpanded((v) => !v)}
             className="mt-1 text-xs text-primary hover:underline"
           >
             展开全文
@@ -174,6 +199,7 @@ export default function MessageBubble({ content }: MessageBubbleProps) {
         </div>
       )}
       {(!isLong || summaryExpanded) && (
+    <>
     <ReactMarkdown
       remarkPlugins={[remarkGfm, remarkMath]}
       rehypePlugins={[rehypeKatex]}
@@ -324,7 +350,21 @@ export default function MessageBubble({ content }: MessageBubbleProps) {
     >
       {content}
     </ReactMarkdown>
+      {summaryExpanded && (
+        <button
+          type="button"
+          onClick={() => {
+            setSummaryExpanded(false);
+          }}
+          className="mt-2 text-xs text-primary hover:underline flex items-center gap-0.5 ml-auto"
+        >
+          收起 ▲
+        </button>
+      )}
+    </>
       )}
     </>
   );
 }
+
+
diff --git a/langgraph/src/components/ThreadSidebar.tsx b/langgraph/src/components/ThreadSidebar.tsx
index aa20170..ac7dde7 100644
--- a/langgraph/src/components/ThreadSidebar.tsx
+++ b/langgraph/src/components/ThreadSidebar.tsx
@@ -80,9 +80,9 @@ export function updateThreadLastActive(threadId: string) {
   }
 }
 
-function formatTime(iso: string) {
+function formatTime(isoOrMs: string | number) {
   try {
-    const d = new Date(iso);
+    const d = typeof isoOrMs === "number" ? new Date(isoOrMs) : new Date(isoOrMs);
     const now = new Date();
     const diffMs = now.getTime() - d.getTime();
     const diffHrs = diffMs / (1000 * 60 * 60);
@@ -224,7 +224,7 @@ export function ThreadSidebar({
                       {displayLabel}
                     </p>
                     <p className="text-[10px] text-muted-foreground">
-                      {formatTime(t.created_at)}
+                      {formatTime(getLastActive(t.thread_id, t.created_at))}
                     </p>
                   </div>
                   <button
diff --git a/langgraph/src/main.tsx b/langgraph/src/main.tsx
index 191dbed..1e0c391 100644
--- a/langgraph/src/main.tsx
+++ b/langgraph/src/main.tsx
@@ -133,7 +133,7 @@ function App() {
   const pendingRetryToolRef = useRef<string | null>(null);
 
   // ── Concurrent submit state ───────────────────────────────────────────────
-  type ConcurrentStatus = "idle" | "generating" | "queued" | "stopping" | "auto-sending";
+  type ConcurrentStatus = "idle" | "generating" | "queued" | "stopping" | "cancelling" | "auto-sending";
 
   // 完整 payload 快照类型
   interface SubmitPayload {
@@ -147,6 +147,7 @@ function App() {
   const [concurrentStatus, setConcurrentStatus] = useState<ConcurrentStatus>("idle");
   const pendingQueueRef = useRef<Array<() => void>>([]);
   const isPollingRef = useRef(false);
+  const wasStoppedRef = useRef(false);
   const [pendingQueueCount, setPendingQueueCount] = useState(0);
 
   const thread = useStream<{ messages: Message[]; ui: UIMsgLocal[] }>({
@@ -175,8 +176,10 @@ function App() {
 
   // Sync concurrent status with thread loading state
   useEffect(() => {
-    if (!thread.isLoading) setConcurrentStatus("idle");
-  }, [thread.isLoading]);
+    if (!thread.isLoading && concurrentStatus !== "cancelling" && concurrentStatus !== "queued") {
+      setConcurrentStatus("idle");
+    }
+  }, [thread.isLoading, concurrentStatus]);
 
   // Listen for retry-tool events from error-result cards
   useEffect(() => {
@@ -431,17 +434,27 @@ function App() {
   function handleConcurrentInterrupt() {
     setShowConcurrentDialog(false);
     setConcurrentStatus("stopping");
+    wasStoppedRef.current = true;
     thread.stop();
     setTimeout(() => {
-      const next = pendingQueueRef.current.shift();
-      if (next) {
-        setPendingQueueCount(pendingQueueRef.current.length);
-        setConcurrentStatus("generating");
-        next();
-      } else {
-        setConcurrentStatus("idle");
-      }
-    }, 300);
+      setConcurrentStatus("cancelling");
+      const waitForStop = () => {
+        if (!thread.isLoading) {
+          wasStoppedRef.current = false;
+          const next = pendingQueueRef.current.shift();
+          if (next) {
+            setPendingQueueCount(pendingQueueRef.current.length);
+            setConcurrentStatus("generating");
+            next();
+          } else {
+            setConcurrentStatus("idle");
+          }
+        } else {
+          setTimeout(waitForStop, 200);
+        }
+      };
+      waitForStop();
+    }, 150);
   }
 
   function handleConcurrentQueue() {
@@ -1014,11 +1027,13 @@ function App() {
               concurrentStatus === "generating"   && "bg-blue-50/80 dark:bg-blue-950/30 text-blue-600 dark:text-blue-400",
               concurrentStatus === "queued"       && "bg-amber-50/80 dark:bg-amber-950/30 text-amber-600 dark:text-amber-400",
               concurrentStatus === "stopping"     && "bg-red-50/80 dark:bg-red-950/30 text-red-600 dark:text-red-400",
+              concurrentStatus === "cancelling"   && "bg-orange-50/80 dark:bg-orange-950/30 text-orange-600 dark:text-orange-400",
               concurrentStatus === "auto-sending" && "bg-green-50/80 dark:bg-green-950/30 text-green-600 dark:text-green-400",
             )}>
               {(concurrentStatus === "generating" || concurrentStatus === "auto-sending") && <Loader2 className="size-3 animate-spin shrink-0" />}
-              {concurrentStatus === "queued"   && <Clock className="size-3 shrink-0" />}
-              {concurrentStatus === "stopping" && <Square className="size-3 shrink-0 fill-current" />}
+              {concurrentStatus === "queued"      && <Clock className="size-3 shrink-0" />}
+              {concurrentStatus === "stopping"    && <Square className="size-3 shrink-0 fill-current" />}
+              {concurrentStatus === "cancelling"  && <Loader2 className="size-3 animate-spin shrink-0" />}
               {concurrentStatus === "queued" ? (
                 <>
                   <span>
@@ -1043,6 +1058,7 @@ function App() {
                 <span>
                   {concurrentStatus === "generating"   && "正在生成回复..."}
                   {concurrentStatus === "stopping"     && "正在停止上一轮..."}
+                  {concurrentStatus === "cancelling"   && "等待当前任务停止..."}
                   {concurrentStatus === "auto-sending" && "正在自动发送下一条..."}
                 </span>
               )}