diff --git a/src/core/pagination.ts b/src/core/pagination.ts
index 6b187e9f5..cb9d5c47c 100644
--- a/src/core/pagination.ts
+++ b/src/core/pagination.ts
@@ -154,7 +154,7 @@ export interface CursorPageParams {
   limit?: number;
 }
 
-export class CursorPage<Item extends { id: string }>
+export class CursorPage<Item extends { id?: string }>
   extends AbstractPage<Item>
   implements CursorPageResponse<Item>
 {
diff --git a/src/resources/responses/responses.ts b/src/resources/responses/responses.ts
index ba1447432..09595ad3f 100644
--- a/src/resources/responses/responses.ts
+++ b/src/resources/responses/responses.ts
@@ -2506,7 +2506,7 @@ export interface ResponseInputMessageItem {
   /**
    * The unique ID of the message input.
    */
-  id: string;
+  id?: string;
 
   /**
    * A list of one or many input items to the model, containing different content