diff --git a/ui/src/ui/app-lifecycle.ts b/ui/src/ui/app-lifecycle.ts
index 66c3b54e77b..ae816a0bdb9 100644
--- a/ui/src/ui/app-lifecycle.ts
+++ b/ui/src/ui/app-lifecycle.ts
@@ -34,7 +34,7 @@ type LifecycleHost = {
   chatLoading: boolean;
   chatMessages: unknown[];
   chatToolMessages: unknown[];
-  chatStream: string;
+  chatStream: string | null;
   logsAutoFollow: boolean;
   logsAtBottom: boolean;
   logsEntries: unknown[];