diff --git a/apps/web/src/components/execution/PhaseActions.tsx b/apps/web/src/components/execution/PhaseActions.tsx
index e92ad97..2187bb1 100644
--- a/apps/web/src/components/execution/PhaseActions.tsx
+++ b/apps/web/src/components/execution/PhaseActions.tsx
@@ -19,9 +19,12 @@ export function PhaseActions({
   const detailMutation = trpc.spawnArchitectDetail.useMutation();
   const [isDetailingAll, setIsDetailingAll] = useState(false);
 
-  // Phases eligible for detailing: no tasks AND no active detail agent
+  // Phases eligible for detailing: no tasks AND no actively running detail agent
   const eligiblePhaseIds = useMemo(
-    () => phasesWithoutTasks.filter((id) => !detailAgentByPhase.has(id)),
+    () => phasesWithoutTasks.filter((id) => {
+      const agent = detailAgentByPhase.get(id);
+      return !agent || agent.status === "idle";
+    }),
     [phasesWithoutTasks, detailAgentByPhase],
   );
 
diff --git a/apps/web/src/components/execution/PhaseDetailPanel.tsx b/apps/web/src/components/execution/PhaseDetailPanel.tsx
index 2a7cbfb..9e72f0c 100644
--- a/apps/web/src/components/execution/PhaseDetailPanel.tsx
+++ b/apps/web/src/components/execution/PhaseDetailPanel.tsx
@@ -207,7 +207,7 @@ export function PhaseDetailPanel({
     detailAgent?.status === "running" ||
     detailAgent?.status === "waiting_for_input";
   const showDetailButton =
-    !detailAgent && !hasTasks;
+    !hasTasks && (!detailAgent || detailAgent.status === "idle");
   const showChangeSet =
     detailAgent?.status === "idle" && !!latestChangeSet;