diff --git a/apps/ai-game-creator-shell/src/App.tsx b/apps/ai-game-creator-shell/src/App.tsx
index f24759d9e..21ff93a40 100644
--- a/apps/ai-game-creator-shell/src/App.tsx
+++ b/apps/ai-game-creator-shell/src/App.tsx
@@ -815,67 +815,69 @@ export function App({
     [gameChatOnly],
   );
 
-  function updateProjectSupervisorResponseStream(
-    incoming: AgentRuntimeResponseStream | null | undefined,
-    runtime: AgentRuntimeState,
-  ) {
-    let nextStream = mergeProjectSupervisorResponseStream(
-      projectSupervisorResponseStreamRef.current,
-      incoming,
-      runtime,
-    );
-    const candidateStream = nextStream;
-    if (candidateStream?.status === 'ready' && gameChatOnly) {
-      const text = candidateStream.accumulatedText.trim();
-      const responseKey = projectSupervisorResponseStreamIdentity(
-        candidateStream,
+  const updateProjectSupervisorResponseStream = useCallback(
+    (
+      incoming: AgentRuntimeResponseStream | null | undefined,
+      runtime: AgentRuntimeState,
+    ) => {
+      let nextStream = mergeProjectSupervisorResponseStream(
+        projectSupervisorResponseStreamRef.current,
+        incoming,
+        runtime,
       );
-      const messageId = `runtime-response:${responseKey}`;
-      const alreadyCommitted =
-        gameChatCommittedResponseStreamKeysRef.current.has(responseKey) ||
+      const candidateStream = nextStream;
+      if (candidateStream?.status === 'ready' && gameChatOnly) {
+        const text = candidateStream.accumulatedText.trim();
+        const responseKey =
+          projectSupervisorResponseStreamIdentity(candidateStream);
+        const messageId = `runtime-response:${responseKey}`;
+        const alreadyCommitted =
+          gameChatCommittedResponseStreamKeysRef.current.has(responseKey) ||
+          latestMessagesRef.current.some(
+            (message) => message.messageId === messageId,
+          );
+        if (text && !alreadyCommitted) {
+          gameChatCommittedResponseStreamKeysRef.current.add(responseKey);
+          const nextMessage: ChatMessage = {
+            role: 'assistant',
+            text: candidateStream.accumulatedText,
+            messageId,
+            agentId: PROJECT_SUPERVISOR_AGENT_ID,
+            updatedAt: candidateStream.updatedAt,
+            runtimeOwned: true,
+          };
+          setMessages((current) => {
+            if (current.some((message) => message.messageId === messageId)) {
+              latestMessagesRef.current = current;
+              return current;
+            }
+            const nextMessages = [...current, nextMessage];
+            latestMessagesRef.current = nextMessages;
+            return nextMessages;
+          });
+        }
+        // Ready text is now a normal chat message; transientReply must not show
+        // the same response a second time while polling/event delivery catches up.
+        nextStream = null;
+      } else if (
+        candidateStream &&
         latestMessagesRef.current.some(
-          (message) => message.messageId === messageId,
-        );
-      if (text && !alreadyCommitted) {
-        gameChatCommittedResponseStreamKeysRef.current.add(responseKey);
-        const nextMessage: ChatMessage = {
-          role: 'assistant',
-          text: candidateStream.accumulatedText,
-          messageId,
-          agentId: PROJECT_SUPERVISOR_AGENT_ID,
-          updatedAt: candidateStream.updatedAt,
-          runtimeOwned: true,
-        };
-        setMessages((current) => {
-          if (current.some((message) => message.messageId === messageId)) {
-            latestMessagesRef.current = current;
-            return current;
-          }
-          const nextMessages = [...current, nextMessage];
-          latestMessagesRef.current = nextMessages;
-          return nextMessages;
-        });
+          (message) =>
+            message.runtimeOwned &&
+            message.role === 'assistant' &&
+            message.text === candidateStream.accumulatedText &&
+            typeof message.updatedAt === 'number' &&
+            message.updatedAt >= candidateStream.startedAt,
+        )
+      ) {
+        // Keep the existing supervisor-chat behavior for restored history.
+        nextStream = null;
       }
-      // Ready text is now a normal chat message; transientReply must not show
-      // the same response a second time while polling/event delivery catches up.
-      nextStream = null;
-    } else if (
-      candidateStream &&
-      latestMessagesRef.current.some(
-        (message) =>
-          message.runtimeOwned &&
-          message.role === 'assistant' &&
-          message.text === candidateStream.accumulatedText &&
-          typeof message.updatedAt === 'number' &&
-          message.updatedAt >= candidateStream.startedAt,
-      )
-    ) {
-      // Keep the existing supervisor-chat behavior for restored history.
-      nextStream = null;
-    }
-    projectSupervisorResponseStreamRef.current = nextStream;
-    setProjectSupervisorResponseStream(nextStream);
-  }
+      projectSupervisorResponseStreamRef.current = nextStream;
+      setProjectSupervisorResponseStream(nextStream);
+    },
+    [gameChatOnly],
+  );
 
   function resetProjectSupervisorState() {
     projectSupervisorHistoryLoadVersionRef.current += 1;
@@ -1155,7 +1157,7 @@ export function App({
       disposed = true;
       cleanup?.();
     };
-  }, [updateProjectSupervisorRuntime]);
+  }, [updateProjectSupervisorResponseStream, updateProjectSupervisorRuntime]);
 
   useEffect(() => {
     const invoke = resolveTauriInvoke();
diff --git a/apps/ai-game-creator-shell/tests/agentRuntimeModel.test.ts b/apps/ai-game-creator-shell/tests/agentRuntimeModel.test.ts
index 7757782ff..746c6c2a5 100644
--- a/apps/ai-game-creator-shell/tests/agentRuntimeModel.test.ts
+++ b/apps/ai-game-creator-shell/tests/agentRuntimeModel.test.ts
@@ -8,12 +8,12 @@ import type {
 } from '../src/app/types';
 import {
   formatAgentRuntimeEvent,
+  mergeGameChatRuntimeResponseMessagesIntoHistory,
   projectRuntimeVisibleCurrentWork,
   projectRuntimeVisibleError,
   projectSupervisorChatRuntimeStatus,
   projectSupervisorResponseStreamIdentity,
   projectSupervisorVisibleConversationText,
-  mergeGameChatRuntimeResponseMessagesIntoHistory,
   submitProjectSupervisorRuntimeTask,
 } from '../src/features/agent-runtime/model';