diff --git a/lightrag/base.py b/lightrag/base.py
index ee13a11f..c44d6af8 100644
--- a/lightrag/base.py
+++ b/lightrag/base.py
@@ -92,7 +92,7 @@ class StorageNameSpace(ABC):
 @dataclass
 class BaseVectorStorage(StorageNameSpace, ABC):
     embedding_func: EmbeddingFunc
-    cosine_better_than_threshold: float
+    cosine_better_than_threshold: float = field(default=0.2)
     meta_fields: set[str] = field(default_factory=set)
 
     @abstractmethod