diff --git a/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.test.ts b/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.test.ts
index 28935038..8da11448 100644
--- a/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.test.ts
+++ b/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.test.ts
@@ -46,3 +46,16 @@ test("conversation panel asks trace panels to collapse after final response appe
 
   assert.match(source, /collapseWhenFinalResponse=\{hasFinalResponse\}/u);
 });
+
+test("conversation panel does not consume replay opportunity before timer fires", async () => {
+  const source = await Bun.file(new URL("./ConversationPanel.tsx", import.meta.url)).text();
+  const effectStart = source.indexOf("const replayRequestedTraceRef = useRef<string | null>(null);");
+  const timerStart = source.indexOf("const timer = window.setTimeout", effectStart);
+  const markRequested = source.indexOf("replayRequestedTraceRef.current = traceId", effectStart);
+  const replayCall = source.indexOf("onReplayTrace();", effectStart);
+
+  assert.ok(effectStart > 0, "replay guard ref exists");
+  assert.ok(timerStart > effectStart, "auto replay uses delayed timer");
+  assert.ok(markRequested > timerStart, "route changes that cancel the timer must not mark replay as already requested");
+  assert.ok(replayCall > markRequested, "replay is marked requested only immediately before dispatching replay");
+});
diff --git a/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.tsx b/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.tsx
index 39b98d97..746d8fa7 100644
--- a/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.tsx
+++ b/web/hwlab-cloud-web/src/components/conversation/ConversationPanel.tsx
@@ -130,12 +130,15 @@ const HISTORICAL_TRACE_REPLAY_DELAY_MS = 4500;
 
 function MessageCard({ message, firstScreenHistory, codeAgentTimeoutMs, onCancel, onRetry, onReplayTrace }: { message: ChatMessage; firstScreenHistory: boolean; codeAgentTimeoutMs: number; onCancel(): void; onRetry(): void; onReplayTrace(): void }): ReactElement {
   const traceKey = `hwlab.workbench.trace-open.${message.traceId ?? message.id}`;
-  const replayRequestedRef = useRef(false);
+  const replayRequestedTraceRef = useRef<string | null>(null);
   useEffect(() => {
-    if (replayRequestedRef.current) return;
+    const traceId = message.traceId ?? message.runnerTrace?.traceId ?? null;
+    if (traceId && replayRequestedTraceRef.current === traceId) return;
     if (!shouldAutoReplayTrace(message)) return;
-    replayRequestedRef.current = true;
-    const timer = window.setTimeout(() => onReplayTrace(), HISTORICAL_TRACE_REPLAY_DELAY_MS);
+    const timer = window.setTimeout(() => {
+      replayRequestedTraceRef.current = traceId;
+      onReplayTrace();
+    }, HISTORICAL_TRACE_REPLAY_DELAY_MS);
     return () => window.clearTimeout(timer);
   }, [message, onReplayTrace]);
   if (message.role === "agent") {