diff --git a/rdagent/factor_implementation/evolving/knowledge_management.py b/rdagent/factor_implementation/evolving/knowledge_management.py
index b92ec6a7..d79f5a81 100644
--- a/rdagent/factor_implementation/evolving/knowledge_management.py
+++ b/rdagent/factor_implementation/evolving/knowledge_management.py
@@ -30,7 +30,6 @@
 from rdagent.factor_implementation.share_modules.factor_implementation_config import (
     FactorImplementSettings,
 )
-from oai.llm_utils import APIBackend, calculate_embedding_distance_between_str_list
 
 
 class FactorImplementationKnowledge(Knowledge):