diff --git a/src/dabmodel/model.py b/src/dabmodel/model.py
index ffc32ae..87ddc32 100644
--- a/src/dabmodel/model.py
+++ b/src/dabmodel/model.py
@@ -55,13 +55,12 @@ def DABField(default: Any = PydanticUndefined, *, final: bool | None = _Unset, f
 T_BaseElement = TypeVar("T_BaseElement", bound="BaseElement")
 T_BaseElement_ConfigMethod_Arg: TypeAlias = dict[str, Any]
 T_BaseElement_ConfigMethod: TypeAlias = "classmethod[T_BaseElement, [T_BaseElement_ConfigMethod_Arg], T_BaseElement_ConfigMethod_Arg]"
-T_BaseElement_ConfigMethod_OrderedSet: TypeAlias = dict[T_BaseElement_ConfigMethod, None]
 
 
 class ConfigElement:
     def __init__(self) -> None:
-        self.default_values_override_methods: T_BaseElement_ConfigMethod_OrderedSet = {}
-        self.main_build_method: T_BaseElement_ConfigMethod_OrderedSet = {}
+        self.default_values_override_methods: dict[T_BaseElement_ConfigMethod, None] = {}
+        self.main_build_method: dict[T_BaseElement_ConfigMethod, None] = {}
 
     def __copy__(self) -> Self:
         # we cannot deepcopy because of classmethods, so we do a manual enhanced copy
@@ -131,6 +130,7 @@ class BaseElement(
     validate_assignment=True,
     # revalidate_instances="subclass-instances", # pydantic issue  #10681
     validate_default=True,
+    extra="forbid",
     metaclass=BaseElementMeta,
 ):
     class Config:
@@ -154,12 +154,19 @@ class BaseElement(
             assert not runtype_issubclass(
                 field_val.annotation, BaseFeature
             ), "Features can only be in Appliance's features[] dict attribute"
+            """
+            if field_key == "features":
+                cls._saved_default_value[field_key] = dict()
+                for feat_key, feat_value in field_val.items():
+                    cls._saved_default_value[field_key][feat_key] = feat_value.dict()
+            """
             if field_val.default != PydanticUndefined:
                 cls._saved_default_value[field_key] = deepcopy(field_val.default)
         for method, _ in cls._config_element.default_values_override_methods.items():
             method.__func__(cls, cls._saved_default_value)
 
         cls._default_values_override_hook__input_apply__(values)
+
         return cls._saved_default_value
 
     @classmethod
@@ -177,10 +184,12 @@ class BaseFeature(BaseElement, ABC):
         cls,
         values: T_BaseElement_ConfigMethod_Arg,
     ):
+        print(f"BaseFeature._default_values_override_hook__input_apply__ {cls}")
         # applying user-defined values
         for attr_key, attr_val in values.items():
             assert attr_key in cls.model_fields, f"given feature attribute does not exist ({attr_key})"
             cls._saved_default_value[attr_key] = attr_val
+        print(f"BaseFeature._default_values_override_hook__input_apply__ {cls} DONE")
 
 
 def default_values_override(func: T_BaseElement_ConfigMethod) -> T_BaseElement_ConfigMethod:
@@ -219,7 +228,7 @@ class BaseAppliance(Generic[T_Feature], BaseElement, ABC):
     @NoInstanceMethod
     @classmethod
     def add_feature(cls, feat: T_Feature):
-        cls._saved_default_value["features"][type(feat).__name__] = feat
+        cls._saved_default_value["features"][type(feat).__name__] = feat.dict()
 
     @NoInstanceMethod
     @classmethod
@@ -237,12 +246,14 @@ class BaseAppliance(Generic[T_Feature], BaseElement, ABC):
         cls,
         values: T_BaseElement_ConfigMethod_Arg,
     ):
+        print(f"BaseAppliance._default_values_override_hook__input_apply__ {cls}")
         # applying user-defined values
         for attr_key, attr_val in values.items():
             if attr_key == "features":
                 if cls._saved_default_value["features"] is None:
                     cls._saved_default_value["features"] = {}
                 for feature_key, feature_val in attr_val.items():
+                    print(f"searching feature: {feature_key}")
                     assert hasattr(cls, feature_key), f"feature not found ({feature_key})"
                     cls_feature = getattr(cls, feature_key)
                     assert (
@@ -253,3 +264,4 @@ class BaseAppliance(Generic[T_Feature], BaseElement, ABC):
             else:
                 assert attr_key in cls.model_fields, f"given attribute does not exist ({attr_key})"
                 cls._saved_default_value[attr_key] = attr_val
+        print(f"BaseAppliance._default_values_override_hook__input_apply__ {cls} DONE")
diff --git a/test/test_model.py b/test/test_model.py
index 26aa631..74ae1ed 100644
--- a/test/test_model.py
+++ b/test/test_model.py
@@ -85,6 +85,7 @@ class MyAppliance2(MyAppliance):
         values["template_long_name"] = "My appliance template 2 !!"
         values["template_description"] = """A very nice Appliance 2"""
         cls.del_feature(MyAppliance.MyFeature)
+        # values["features"]["MyFeature2"].template_description = """Override feature desc"""
 
 
 class MyAppliance3(dabmodel.BaseAppliance):
@@ -135,8 +136,9 @@ class MyAppliance3(dabmodel.BaseAppliance):
 class MyAppliance4(MyAppliance):
 
     class MyFeature8(dabmodel.BaseFeature):
-        # testtt: Annotated[MyAppliance.MyFeature, Field(MyAppliance.MyFeature())] # error case
-        test_integer_10: Annotated[int, dabmodel.DABField(3189, ge=0)]
+        # testtt: Annotated[MyAppliance.MyFeature, Field(MyAppliance.MyFeature())]  # error case (nested feature)
+        # test_integer_10: Annotated[int, dabmodel.DABField(3189, ge=0, toto="tata")] # error case (extra field)
+        test_integer_10: Annotated[int, dabmodel.DABField(3189, ge=0, toto="tata")]
 
         @dabmodel.default_values_override
         @classmethod
@@ -146,9 +148,10 @@ class MyAppliance4(MyAppliance):
             values["template_short_name"] = "my-feature-8"
             values["template_long_name"] = "My appliance template 8 !!"
             values["template_description"] = """A very nice Appliance 8"""
-            values["test_integer_2"] = 951753
+            values["test_integer_10"] = 951753
+            # values["tete"] = 1 # error case (extra field in feature)
 
-    # testtt: Annotated[MyAppliance.MyFeature, Field(MyAppliance.MyFeature())] # error case
+    # testtt: Annotated[MyAppliance.MyFeature, Field(MyAppliance.MyFeature())]  # error case (feature not in features[] list)
 
     @dabmodel.default_values_override
     @classmethod