diff --git a/crudkit/core/service.py b/crudkit/core/service.py
index 5126a9b..98b6c86 100644
--- a/crudkit/core/service.py
+++ b/crudkit/core/service.py
@@ -9,9 +9,10 @@ def _is_truthy(val):
     return str(val).lower() in ('1', 'true', 'yes', 'on')
 
 class CRUDService(Generic[T]):
-    def __init__(self, model: Type[T], session: Session):
+    def __init__(self, model: Type[T], session: Session, polymorphic: bool = False):
         self.model = model
         self.session = session
+        self.polymorphic = polymorphic
         self.supports_soft_delete = hasattr(model, 'is_deleted')
 
     def get(self, id: int, include_deleted: bool = False) -> T | None: