diff --git a/apps/mobile/src/features/threads/ThreadFeed.tsx b/apps/mobile/src/features/threads/ThreadFeed.tsx
index 77729684a792e..f9195409d095f 100644
--- a/apps/mobile/src/features/threads/ThreadFeed.tsx
+++ b/apps/mobile/src/features/threads/ThreadFeed.tsx
@@ -1734,6 +1734,33 @@ function ThreadFeedPlaceholder(props: {
   );
 }
 
+// A hook's return value is frozen to the compiler, so ThreadFeed's later
+// hooks can't drag this derivation into an uncached scope.
+function useThreadFeedPresentation(
+  props: ThreadFeedProps,
+  expandedTurnIds: ReadonlySet<RunId>,
+  expandedWorkGroups: Record<string, boolean>,
+) {
+  const [feedCache] = useState(createThreadFeedCache);
+  return appendPendingThreadMessages(
+    deriveThreadFeedPresentation(
+      props.feed,
+      props.latestRun,
+      expandedTurnIds,
+      new Set(
+        Object.entries(expandedWorkGroups)
+          .filter(([, expanded]) => expanded)
+          .map(([groupId]) => groupId),
+      ),
+      props.activeWorkStartedAt,
+      props.runlessWorkActive ?? false,
+      feedCache,
+    ),
+    props.feed,
+    props.queuedMessages,
+  );
+}
+
 export const ThreadFeed = memo(function ThreadFeed(props: ThreadFeedProps) {
   const { listRef, onEndFollowEnabledChange, onHeaderMaterialVisibilityChange } = props;
   const workflowOpening = useWorkflowOpening(props.environmentId, props.threadId);
@@ -1759,7 +1786,6 @@ export const ThreadFeed = memo(function ThreadFeed(props: ThreadFeedProps) {
   const disclosureSettleFrameRef = useRef<number | null>(null);
   const disclosureSettleSecondFrameRef = useRef<number | null>(null);
   const disclosureAnchorKeyRef = useRef<string | null>(null);
-  const [feedCache] = useState(createThreadFeedCache);
   const previousLatestTurnRef = useRef(props.latestRun);
   const userScrollSettleTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const headerMaterialVisibleRef = useRef(false);
@@ -2315,23 +2341,7 @@ export const ThreadFeed = memo(function ThreadFeed(props: ThreadFeedProps) {
     reportHeaderMaterialVisibility(false);
   }, [feedThreadKey, reportHeaderMaterialVisibility]);
 
-  const presentedFeed = appendPendingThreadMessages(
-    deriveThreadFeedPresentation(
-      props.feed,
-      props.latestRun,
-      expandedTurnIds,
-      new Set(
-        Object.entries(expandedWorkGroups)
-          .filter(([, expanded]) => expanded)
-          .map(([groupId]) => groupId),
-      ),
-      props.activeWorkStartedAt,
-      props.runlessWorkActive ?? false,
-      feedCache,
-    ),
-    props.feed,
-    props.queuedMessages,
-  );
+  const presentedFeed = useThreadFeedPresentation(props, expandedTurnIds, expandedWorkGroups);
   const setupAnchorIndex = presentedFeed.findIndex(
     (entry) => entry.type === "message" && entry.message.role === "user",
   );