diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index e628f6ea6a..4f09c7e1dc 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -660,7 +660,6 @@ export default function ChatView({ threadId }: ChatViewProps) {
   const phase = derivePhase(activeThread?.session ?? null);
   const isSendBusy = sendPhase !== "idle";
   const isPreparingWorktree = sendPhase === "preparing-worktree";
-  const isWorking = phase === "running" || isSendBusy || isConnecting || isRevertingCheckpoint;
   const nowIso = new Date(nowTick).toISOString();
   const activeWorkStartedAt = deriveActiveWorkStartedAt(
     activeLatestTurn,
@@ -684,6 +683,13 @@ export default function ChatView({ threadId }: ChatViewProps) {
     () => derivePendingUserInputs(threadActivities),
     [threadActivities],
   );
+  // phase === "running" alone isn't sufficient: the session can stay "running" even after
+  // the latest turn has completed (server lifecycle guard can reject status updates while
+  // completedAt is set through a separate path) or while waiting for user input.
+  // Use completedAt on the latest turn as the reliable completion signal.
+  const turnDone = !!activeLatestTurn?.completedAt;
+  const isActivelyRunning = phase === "running" && pendingUserInputs.length === 0 && !turnDone;
+  const isWorking = isActivelyRunning || isSendBusy || isConnecting || isRevertingCheckpoint;
   const activePendingUserInput = pendingUserInputs[0] ?? null;
   const activePendingDraftAnswers = useMemo(
     () =>
diff --git a/apps/web/src/components/Sidebar.logic.ts b/apps/web/src/components/Sidebar.logic.ts
index ef338dab67..abc52754ac 100644
--- a/apps/web/src/components/Sidebar.logic.ts
+++ b/apps/web/src/components/Sidebar.logic.ts
@@ -115,7 +115,11 @@ export function resolveThreadStatusPill(input: {
     };
   }
 
-  if (thread.session?.status === "running") {
+  // Use completedAt as the reliable completion signal — activeTurnId can be permanently
+  // stale when the server lifecycle guard rejects status updates.
+  const sidebarTurnDone = !!thread.latestTurn?.completedAt;
+
+  if (thread.session?.status === "running" && !sidebarTurnDone) {
     return {
       label: "Working",
       colorClass: "text-sky-600 dark:text-sky-300/80",