diff --git a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
index 9c77f1f8..5426dbdf 100644
--- a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
+++ b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
@@ -28,6 +28,14 @@ const { following, keepBottomAfterUpdate, onScroll: onPanelScroll, scrollToBotto
 const detailMessageId = ref<string | null>(null);
 const displayedDurationFloorMs = new Map<string, number>();
 const sealedDurationMs = new Map<string, number>();
+type VisibleTimingSample = {
+  durationMs?: number;
+  durationObservedAtMs?: number;
+  lastEventAgeMs?: number;
+  lastEventObservedAtMs?: number;
+  lastEventSourceMs?: number;
+};
+const visibleTimingSamples = new Map<string, VisibleTimingSample>();
 const visibleMessages = computed(() => workbench.sessionDetailLoading ? [] : workbench.activeMessages);
 const hasRunningAgentMessages = computed(() => visibleMessages.value.some(isRunningMessage));
 const { nowMs } = useWorkbenchNowTicker(hasRunningAgentMessages);
@@ -66,6 +74,9 @@ watch(visibleMessages, (messages) => {
   for (const key of Array.from(sealedDurationMs.keys())) {
     if (!visibleKeys.has(key)) sealedDurationMs.delete(key);
   }
+  for (const key of Array.from(visibleTimingSamples.keys())) {
+    if (!visibleKeys.has(key)) visibleTimingSamples.delete(key);
+  }
 }, { immediate: true });
 
 function openDetails(message: ChatMessage): void {
@@ -269,8 +280,12 @@ function messageDurationMeta(message: ChatMessage): { text: string; label: strin
 function monotonicDisplayDurationMs(message: ChatMessage, durationMs: number | null): number | null {
   if (durationMs === null) return null;
   const key = messageDurationFloorKey(message);
-  const previous = displayedDurationFloorMs.get(key);
-  const next = previous === undefined ? durationMs : Math.max(previous, durationMs);
+  const sample = visibleTimingSamples.get(key) ?? {};
+  const previous = sample.durationMs ?? displayedDurationFloorMs.get(key);
+  const next = smoothVisibleIncreasingDurationMs(previous, sample.durationObservedAtMs, durationMs, nowMs.value);
+  sample.durationMs = next;
+  sample.durationObservedAtMs = nowMs.value;
+  visibleTimingSamples.set(key, sample);
   if (next !== previous) displayedDurationFloorMs.set(key, next);
   return next;
 }
@@ -281,12 +296,21 @@ function sealedDisplayDurationMs(message: ChatMessage, durationMs: number | null
   const sealedFloor = sealedDurationMs.get(key);
   const previous = maxDefinedDurationMs(runningFloor, sealedFloor);
   displayedDurationFloorMs.delete(key);
+  visibleTimingSamples.delete(key);
   if (durationMs === null) return previous ?? null;
   const next = previous === null ? durationMs : Math.max(previous, durationMs);
   if (next !== previous) sealedDurationMs.set(key, next);
   return next;
 }
 
+function smoothVisibleIncreasingDurationMs(previous: number | undefined, previousObservedAtMs: number | undefined, targetMs: number, observedAtMs: number): number {
+  const target = Math.max(0, Math.trunc(targetMs));
+  if (previous === undefined || !Number.isFinite(previous)) return target;
+  const elapsedSincePreviousSample = Number.isFinite(previousObservedAtMs) ? Math.max(0, observedAtMs - Number(previousObservedAtMs)) : 0;
+  const visibleCeiling = previous + elapsedSincePreviousSample;
+  return Math.max(previous, Math.min(target, Math.trunc(visibleCeiling)));
+}
+
 function maxDefinedDurationMs(...values: Array<number | undefined>): number | null {
   let maximum: number | null = null;
   for (const value of values) {
@@ -303,12 +327,34 @@ function messageDurationFloorKey(message: ChatMessage): string {
 function messageActivityMeta(message: ChatMessage): { text: string; label: string } | null {
   if (!isRunningMessage(message)) return null;
   const timing = messageTimingForDisplay(message);
-  const ageMs = durationSince(timing?.lastEventAt);
+  const ageMs = visibleLastEventAgeMs(message, timing?.lastEventAt);
   if (ageMs === null) return null;
   const value = formatDuration(ageMs) + "前";
   return { text: `最近 ${value}`, label: `最近事件：${value}` };
 }
 
+function visibleLastEventAgeMs(message: ChatMessage, timestamp: unknown): number | null {
+  const eventAtMs = timestampMs(timestamp);
+  if (eventAtMs === null) return null;
+  const key = messageDurationFloorKey(message);
+  const sample = visibleTimingSamples.get(key) ?? {};
+  const now = nowMs.value;
+  const targetAgeMs = Math.max(0, now - eventAtMs);
+  let nextAgeMs: number;
+  if (sample.lastEventAgeMs === undefined || !Number.isFinite(sample.lastEventAgeMs)) {
+    nextAgeMs = targetAgeMs;
+  } else if (sample.lastEventSourceMs !== undefined && eventAtMs > sample.lastEventSourceMs) {
+    nextAgeMs = 0;
+  } else {
+    nextAgeMs = smoothVisibleIncreasingDurationMs(sample.lastEventAgeMs, sample.lastEventObservedAtMs, targetAgeMs, now);
+  }
+  sample.lastEventAgeMs = nextAgeMs;
+  sample.lastEventObservedAtMs = now;
+  sample.lastEventSourceMs = eventAtMs;
+  visibleTimingSamples.set(key, sample);
+  return nextAgeMs;
+}
+
 function messageTimingForDisplay(message: ChatMessage): ChatMessage["timing"] {
   // The main message card consumes only the durable message timing projection.
   // Trace timing belongs to TraceTimeline/details; letting trace hydration drive the