diff --git a/ui/src/ui/app-view-state.ts b/ui/src/ui/app-view-state.ts
index 375faa43137..6716fd96a0a 100644
--- a/ui/src/ui/app-view-state.ts
+++ b/ui/src/ui/app-view-state.ts
@@ -72,6 +72,7 @@ export type AppViewState = {
   fallbackStatus: FallbackStatus | null;
   chatAvatarUrl: string | null;
   chatThinkingLevel: string | null;
+  chatHistoryTruncated?: boolean;
   chatModelOverrides: Record<string, ChatModelOverride | null>;
   chatModelsLoading: boolean;
   chatModelCatalog: ModelCatalogEntry[];