diff --git a/AIStudyApp/AIStudyApp/Features/Library/LibrarySubpages.swift b/AIStudyApp/AIStudyApp/Features/Library/LibrarySubpages.swift
index 984f455..c973d08 100644
--- a/AIStudyApp/AIStudyApp/Features/Library/LibrarySubpages.swift
+++ b/AIStudyApp/AIStudyApp/Features/Library/LibrarySubpages.swift
@@ -144,9 +144,11 @@ struct LibraryDetailPage: View {
     @State private var detailTab = 1
 
     private func appear() async {
-        // Load KB info and sources
+        print("[LibraryDetail] appear() START, kbId=\(knowledgeBaseId)")
         viewModel.knowledgeBase = try? await KnowledgeBaseService.shared.detail(id: knowledgeBaseId)
+        print("[LibraryDetail] KB loaded: \(viewModel.knowledgeBase?.title ?? "nil")")
         await loadSources()
+        print("[LibraryDetail] appear() DONE")
     }
     @State private var sortOption = 0
     @State private var showFolderManager = false
@@ -640,16 +642,16 @@ struct LibraryDetailPage: View {
 
     private func loadSources() async {
         isLoadingSources = true
-        do { sources = try await KnowledgeSourceService.shared.list(kbId: knowledgeBaseId) } catch {}
-        // Fetch reading status for sources
-        for src in sources.prefix(20) {
-            if let progress = try? await ReadingAPIService.shared.getReadingProgress(
-                materialId: src.id, targetType: "knowledge_source"
-            ) {
-                sourceReadingStatus[src.id] = progress.isMarkedRead ? "read" : progress.status
-            } else if MarkedReadStore.shared.contains(src.id) {
-                sourceReadingStatus[src.id] = "read"
+        print("[LibraryDetail] loadSources START, kbId=\(knowledgeBaseId)")
+        do {
+            sources = try await KnowledgeSourceService.shared.list(kbId: knowledgeBaseId)
+            print("[LibraryDetail] loadSources OK, count=\(sources.count)")
+            for src in sources {
+                print("[LibraryDetail]   source: id=\(src.id), title=\(src.title ?? "-"), parseStatus=\(src.parseStatus ?? "-")")
             }
+        } catch {
+            print("[LibraryDetail] loadSources ERROR: \(error.localizedDescription)")
+            print("[LibraryDetail] Full error: \(error)")
         }
         isLoadingSources = false
     }