diff --git a/AIStudyApp/AIStudyApp/Core/Models/APIModels.swift b/AIStudyApp/AIStudyApp/Core/Models/APIModels.swift
index 2977484..8b2232c 100644
--- a/AIStudyApp/AIStudyApp/Core/Models/APIModels.swift
+++ b/AIStudyApp/AIStudyApp/Core/Models/APIModels.swift
@@ -174,7 +174,7 @@ struct KnowledgeBase: Codable, Identifiable {
 struct CreateKnowledgeBaseRequest: Codable {
     let title: String
     let description: String?
-    let coverKey: String?
+    var coverKey: String? = nil
 }
 
 struct KnowledgeBaseCoverUploadResult {