diff --git a/backend/app/services/llm_graph_builder.py b/backend/app/services/llm_graph_builder.py
index bbb2c69..9326b51 100644
--- a/backend/app/services/llm_graph_builder.py
+++ b/backend/app/services/llm_graph_builder.py
@@ -122,7 +122,9 @@ class LLMGraphBuilderService:
             except Exception as e:
                 fail_count += 1
                 last_error = e
-                logger.error(f"Chunk {i+1} extraction failed: {e}")
+                import traceback
+                logger.error(f"Chunk {i+1} extraction failed: {type(e).__name__}: {e}")
+                logger.error(f"Chunk {i+1} traceback: {traceback.format_exc()}")
                 if progress_callback:
                     progress_callback(f"Chunk {i+1} error: {e}", (i + 1) / total)