diff --git a/src/autoencoder/model/base.py b/src/autoencoder/model/base.py
index d648dbe..1f74cab 100644
--- a/src/autoencoder/model/base.py
+++ b/src/autoencoder/model/base.py
@@ -6,20 +6,36 @@
 from typing import Any
 from typing import Dict
 from typing import Generator
+from typing import Iterator
 from typing import Optional
 from typing import Tuple
 
 import keras
 from keras.layers import Layer
-from typing_extensions import TypeAlias
 
 
-# custom types
-DefaultParams: TypeAlias = Dict[str, Tuple[Layer, Dict[str, Any]]]
+@dataclass
+class MetaLayer:
+    """Container for a keras Layer and its kwargs."""
+
+    layer: Layer
+    params: Dict[str, Any]
+
+    def __iter__(self) -> Iterator[Any]:
+        """Define iteration behavior."""
+        return iter((self.layer, self.params))
+
 
+class Encode(MetaLayer):
+    """Designate a meta layer as an ecoding layer."""
 
-class BaseLayerParams(ABC):
-    """Autoencoder layers hyperparameters configuration base class."""
+
+class Decode(MetaLayer):
+    """Designate a meta layer as a decoding layer."""
+
+
+class BaseModelParams(ABC):
+    """Autoencoder model layer hyperparameters configuration base class."""
 
     @abstractmethod
     def __init__(self, **kwargs: Dict[str, Any]) -> None:
@@ -28,7 +44,7 @@ def __init__(self, **kwargs: Dict[str, Any]) -> None:
 
     @property
     @abstractmethod
-    def default_parameters(self) -> DefaultParams:
+    def default_parameters(self) -> Dict[str, MetaLayer]:
         """Defines the required default layer parameters attribute."""
         # NOTE: this dictionary sets layer order used to build the keras.Model
         pass
@@ -53,24 +69,25 @@ def _filter_layer_attrs(self) -> Generator[Tuple[str, Dict[str, Any]], None, Non
             # finally get value of constructor args
             yield layer_id, self.__dict__[layer_id]
 
-    def _update_layer_params(
-        self,
-    ) -> Generator[Tuple[Layer, Dict[str, Any]], None, None]:
+    def _update_layer_params(self) -> Generator[MetaLayer, None, None]:
         """Update default layer parameters values."""
         # get layer instance attrs and their values
         for attr, value in self._filter_layer_attrs():
             # unpack default parameters
             layer, params = self.default_parameters[attr]
 
+            # get copy of default params
+            default_params_copy = params.copy()
+
             # check if none
             if value is not None:
-                # merge instance onto default
-                params |= value
+                # update default with any user supplied kwargs
+                default_params_copy |= value
 
             # generate
-            yield layer, params
+            yield MetaLayer(layer, default_params_copy)
 
-    def _build_instance_params(self) -> Tuple[Tuple[Layer, Dict[str, Any]], ...]:
+    def _build_instance_params(self) -> Tuple[MetaLayer, ...]:
         """Create mutable sequence of layer params for instance."""
         return tuple(self._update_layer_params())
 
@@ -79,7 +96,7 @@ def _build_instance_params(self) -> Tuple[Tuple[Layer, Dict[str, Any]], ...]:
 class BaseAutoencoder(ABC):
     """Autoencoder base class."""
 
-    model_config: Optional[BaseLayerParams] = None
+    model_config: Optional[BaseModelParams] = None
 
     def __post_init__(self) -> None:
         """Setup autoencoder model."""
@@ -93,7 +110,7 @@ def __post_init__(self) -> None:
 
     @property
     @abstractmethod
-    def _default_config(self) -> BaseLayerParams:
+    def _default_config(self) -> BaseModelParams:
         """Defines the default layer parameters attribute."""
         pass