diff --git a/selfdrive/car/data_test.py b/selfdrive/car/data_test.py
new file mode 100644
index 00000000000000..ba676ab2b3f76c
--- /dev/null
+++ b/selfdrive/car/data_test.py
@@ -0,0 +1,38 @@
+# sentinel value to detect when to replace a field's default
+from dataclasses import dataclass, field
+
+auto = object()
+
+
+def check_auto(name, bases, cls_dict):
+  default = 1
+
+  cls_annotations = cls_dict.get('__annotations__', {})
+  print('cls_annotations2', cls_annotations)
+
+  for name, val in cls_dict.items():
+    print('test', name, val)
+    if val == auto:
+      # cls_dict[name] = default
+      # cls_dict[name] = cls_annotations[name]
+      cls_dict[name] = field(default_factory=cls_annotations[name])
+      default += 1
+
+  cls = type(name, bases, cls_dict)
+  return cls
+
+
+@dataclass(frozen=True)
+class State(metaclass=check_auto):
+  test: int = auto
+  test2: str = auto
+  test3: bool = auto
+
+
+s = State()
+# print(s)  # State(val_A=1, val_B=2, val_C=3)
+# assert s.val_B == 2
+#
+# s = State(val_A=5)
+# assert s.val_A == 5
+# assert s.val_C == 3
diff --git a/selfdrive/car/data_test2.py b/selfdrive/car/data_test2.py
new file mode 100644
index 00000000000000..57f869c8161957
--- /dev/null
+++ b/selfdrive/car/data_test2.py
@@ -0,0 +1,40 @@
+class Auto:
+  """A placeholder class to denote an automatically assigned default value."""
+
+  def __repr__(self):
+    return "<Auto>"
+
+
+from dataclasses import dataclass, field, fields as dc_fields
+from typing import Any, List
+
+def apply_auto_defaults(cls):
+    for f in dc_fields(cls):
+        # Check if the field's default is an instance of Auto
+        if isinstance(f.default, Auto):
+            # Determine the appropriate default factory based on type hints
+            if f.type == bool:
+                default_factory = bool
+            elif f.type == list:
+                default_factory = list
+            elif f.type == int:
+                default_factory = int
+            else:
+                raise TypeError(f"Unsupported field type for auto-default: {f.type}")
+            # Replace the placeholder with an actual dataclass field with default_factory
+            setattr(cls, f.name, field(default_factory=default_factory))
+    return cls
+
+
+@apply_auto_defaults
+@dataclass
+class CarControl:
+    enabled: bool = Auto()  # Auto will be replaced with field(default_factory=bool)
+    speed: int = Auto()     # Auto will be replaced with field(default_factory=int)
+    tags: List[str] = Auto()  # Auto will be replaced with field(default_factory=list)
+
+# This will instantiate the dataclass with the fields set to their default types
+car_control = CarControl()
+print(car_control.enabled)  # Expected: False
+print(car_control.speed)    # Expected: 0
+print(car_control.tags)     # Expected: []