diff --git a/desktop/src/features/messages/ui/TimelineMessageList.tsx b/desktop/src/features/messages/ui/TimelineMessageList.tsx
index d1186ef2eb..4f149cf097 100644
--- a/desktop/src/features/messages/ui/TimelineMessageList.tsx
+++ b/desktop/src/features/messages/ui/TimelineMessageList.tsx
@@ -283,6 +283,13 @@ export const TimelineMessageList = React.memo(function TimelineMessageList({
           {group.items.map((item) => (
             <div
               className="timeline-row-cv"
+              data-agent-working={
+                item.kind === "message" &&
+                item.entry.summary != null &&
+                workingThreadHeadIds?.has(item.entry.message.id)
+                  ? "true"
+                  : undefined
+              }
               key={getTimelineItemKey(item)}
               style={timelineRowReserveStyle(item)}
             >
diff --git a/desktop/src/shared/styles/globals/utilities.css b/desktop/src/shared/styles/globals/utilities.css
index 461409e91a..d84df68b37 100644
--- a/desktop/src/shared/styles/globals/utilities.css
+++ b/desktop/src/shared/styles/globals/utilities.css
@@ -22,6 +22,15 @@
     content-visibility: visible;
   }
 
+  /* Rows with an animated working badge must stay painted: under
+     content-visibility: auto the browser may skip/throttle rendering work for
+     off-screen or contained rows, which makes the badge pulse stutter on
+     closed thread ingress rows (the open-thread panel has no containment and
+     animates smoothly). Scoped to the 1-2 rows with active agent work. */
+  .timeline-row-cv[data-agent-working="true"] {
+    content-visibility: visible;
+  }
+
   .content-visibility-auto-interactive {
     content-visibility: auto;
     contain-intrinsic-size: auto 200px;