diff --git a/packages/ui/src/components/message-part.tsx b/packages/ui/src/components/message-part.tsx
index 9bc6e6550..01a6fb5f5 100644
--- a/packages/ui/src/components/message-part.tsx
+++ b/packages/ui/src/components/message-part.tsx
@@ -603,7 +603,9 @@ ToolRegistry.register({
         icon="checklist"
         trigger={{
           title: "To-dos",
-          subtitle: `${props.input.todos?.filter((t: any) => t.status === "completed").length}/${props.input.todos?.length}`,
+          subtitle: props.input.todos
+            ? `${props.input.todos.filter((t: any) => t.status === "completed").length}/${props.input.todos.length}`
+            : "",
         }}
       >
         <Show when={props.input.todos?.length}>