diff --git a/web/hwlab-cloud-web/scripts/workbench-trace-lifecycle.test.ts b/web/hwlab-cloud-web/scripts/workbench-trace-lifecycle.test.ts
new file mode 100644
index 00000000..ecaa7976
--- /dev/null
+++ b/web/hwlab-cloud-web/scripts/workbench-trace-lifecycle.test.ts
@@ -0,0 +1,19 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import type { ChatMessage } from "../src/types/index.ts";
+import { traceLifecycleExpanded } from "../src/components/workbench/trace-lifecycle.ts";
+
+test("Trace lifecycle expands only active agent turns", () => {
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "running", runnerTrace: { status: "running" } })), true);
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "running", runnerTrace: { status: "pending" } })), true);
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "completed", runnerTrace: { status: "running" } })), false);
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "running", runnerTrace: { status: "completed" } })), false);
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "running", runnerTrace: { status: "running", finalResponse: "ok" } })), false);
+  assert.equal(traceLifecycleExpanded(agentMessage({ status: "failed", runnerTrace: { status: "failed" } })), false);
+  assert.equal(traceLifecycleExpanded({ ...agentMessage({ status: "running" }), role: "user", title: "用户" }), false);
+});
+
+function agentMessage(patch: Partial<ChatMessage>): ChatMessage {
+  return { id: "msg_trace_lifecycle", role: "agent", title: "Code Agent", text: "", status: "running", createdAt: "2026-06-15T00:00:00.000Z", ...patch };
+}
diff --git a/web/hwlab-cloud-web/src/components/agent/TraceTimeline.vue b/web/hwlab-cloud-web/src/components/agent/TraceTimeline.vue
index f789fe50..93b759d9 100644
--- a/web/hwlab-cloud-web/src/components/agent/TraceTimeline.vue
+++ b/web/hwlab-cloud-web/src/components/agent/TraceTimeline.vue
@@ -6,7 +6,7 @@ import MessageMarkdown from "@/components/workbench/MessageMarkdown.vue";
 import { traceEventBody, traceEventLabel, traceEventMeta } from "@/components/workbench/message-rendering";
 import { traceDisplayRows, traceNoiseEventCount, type TraceEventRow } from "../../../../../tools/src/hwlab-cli/trace-renderer.ts";
 
-const props = defineProps<{ trace?: RunnerTrace | null; defaultExpanded?: boolean; storageKey?: string }>();
+const props = defineProps<{ trace?: RunnerTrace | null; defaultExpanded?: boolean; storageKey?: string; autoExpanded?: boolean | null }>();
 
 const listRef = ref<HTMLOListElement | null>(null);
 const following = ref(true);
@@ -40,9 +40,15 @@ watch(() => [eventCount.value, props.trace?.status, following.value, expanded.va
 });
 
 watch(() => [props.trace?.traceId, props.storageKey, props.defaultExpanded] as const, () => {
+  if (typeof props.autoExpanded === "boolean") return;
   expanded.value = readStoredExpanded() ?? props.defaultExpanded ?? false;
 }, { immediate: true });
 
+watch(() => [props.trace?.traceId, props.autoExpanded] as const, () => {
+  if (typeof props.autoExpanded !== "boolean") return;
+  expanded.value = props.autoExpanded;
+}, { immediate: true });
+
 watch(expanded, (value) => {
   if (!props.storageKey) return;
   try { window.localStorage.setItem(props.storageKey, value ? "1" : "0"); } catch { /* ignore */ }
diff --git a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
index 99d9764e..daf49fe4 100644
--- a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
+++ b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
@@ -9,6 +9,7 @@ import MessageMarkdown from "@/components/workbench/MessageMarkdown.vue";
 import { useClipboard } from "@/composables/useClipboard";
 import { useWorkbenchStore } from "@/stores/workbench";
 import { traceIdentityText } from "./message-rendering";
+import { traceLifecycleExpanded } from "./trace-lifecycle";
 
 const workbench = useWorkbenchStore();
 const clipboard = useClipboard();
@@ -60,11 +61,6 @@ function scrollToBottom(): void {
   panel.scrollTop = panel.scrollHeight;
 }
 
-function traceDefaultExpanded(message: ChatMessage): boolean {
-  void message;
-  return false;
-}
-
 function traceStorageKey(message: ChatMessage): string {
   return `hwlab.workbench.trace-open.${message.traceId ?? message.runnerTrace?.traceId ?? message.id}`;
 }
@@ -81,7 +77,7 @@ function traceStorageKey(message: ChatMessage): string {
           <button v-if="message.role === 'agent'" class="message-detail-button" type="button" aria-label="运行详情" title="运行详情" @click="openDetails(message)">!</button>
         </div>
       </header>
-      <TraceTimeline v-if="message.role === 'agent' && message.runnerTrace" :trace="message.runnerTrace" :default-expanded="traceDefaultExpanded(message)" :storage-key="traceStorageKey(message)" />
+      <TraceTimeline v-if="message.role === 'agent' && message.runnerTrace" :trace="message.runnerTrace" :auto-expanded="traceLifecycleExpanded(message)" :storage-key="traceStorageKey(message)" />
       <MessageMarkdown class="message-text" :source="message.text" />
     </article>
     <div v-if="workbench.messages.length === 0" class="conversation-empty-hint">发起对话，或从左侧选择 session。</div>
diff --git a/web/hwlab-cloud-web/src/components/workbench/trace-lifecycle.ts b/web/hwlab-cloud-web/src/components/workbench/trace-lifecycle.ts
new file mode 100644
index 00000000..b0df7218
--- /dev/null
+++ b/web/hwlab-cloud-web/src/components/workbench/trace-lifecycle.ts
@@ -0,0 +1,40 @@
+import type { ChatMessage } from "@/types";
+
+export function traceLifecycleExpanded(message: ChatMessage): boolean {
+  if (message.role !== "agent") return false;
+  if (hasTraceTerminalSignal(message)) return false;
+  return traceStatusValues(message).some(isTraceActiveStatus);
+}
+
+function hasTraceTerminalSignal(message: ChatMessage): boolean {
+  if (hasFinalResponseValue(message.finalResponse) || hasFinalResponseValue(message.runnerTrace?.finalResponse)) return true;
+  return traceStatusValues(message).some(isTraceTerminalStatus);
+}
+
+function traceStatusValues(message: ChatMessage): string[] {
+  return [
+    message.status,
+    message.runnerTrace?.status,
+    message.runnerTrace?.traceStatus
+  ].map(normalizeTraceStatus).filter((value): value is string => Boolean(value));
+}
+
+function normalizeTraceStatus(value: unknown): string | null {
+  const text = String(value ?? "").trim().toLowerCase().replace(/_/gu, "-");
+  return text || null;
+}
+
+function isTraceActiveStatus(status: string): boolean {
+  return ["accepted", "pending", "processing", "running", "busy", "creating", "queued"].includes(status);
+}
+
+function isTraceTerminalStatus(status: string): boolean {
+  return ["completed", "failed", "blocked", "timeout", "canceled", "cancelled", "aborted", "error", "done"].includes(status);
+}
+
+function hasFinalResponseValue(value: unknown): boolean {
+  if (value == null) return false;
+  if (typeof value === "string") return value.trim().length > 0;
+  if (typeof value === "object") return Object.keys(value as Record<string, unknown>).length > 0;
+  return true;
+}