diff --git a/src/dabmodel/model.py b/src/dabmodel/model.py
index 57adf45..f02ad3d 100644
--- a/src/dabmodel/model.py
+++ b/src/dabmodel/model.py
@@ -31,7 +31,7 @@ import inspect, ast, textwrap
 from frozendict import deepfreeze
 from typeguard import check_type, TypeCheckError, CollectionCheckStrategy
 
-ALLOWED_ANNOTATIONS: dict[str, type] = {
+ALLOWED_ANNOTATIONS: dict[str, Any] = {
     "Union": Union,
     "Optional": Optional,
     "List": List,
@@ -55,7 +55,14 @@ ALLOWED_ANNOTATIONS: dict[str, type] = {
     "tuple": tuple,
 }
 
-ALLOWED_MODEL_FIELDS_TYPES: tuple[type] = (str, int, float, complex, bool, bytes)
+ALLOWED_MODEL_FIELDS_TYPES: tuple[type[Any], ...] = (
+    str,
+    int,
+    float,
+    complex,
+    bool,
+    bytes,
+)
 
 
 class DABModelException(Exception):
diff --git a/test/test_model.py b/test/test_model.py
index 0956450..e636f0e 100644
--- a/test/test_model.py
+++ b/test/test_model.py
@@ -1876,14 +1876,6 @@ class MainTests(unittest.TestCase):
         self.immutable_vars__test_field(app2, "testVar5", ("a", "b"), ("h", "c"))
         self.immutable_vars__test_field(app2, "testVar6", ("a", "b"), ("h", "c"))
 
-    def test_field_is_readonly(self):
-        class App(dm.BaseAppliance):
-            x: int = 1
-
-        app = App()
-        with self.assertRaises(dm.ReadOnlyField):
-            app.x = 2
-
     def test_new_field_forbidden(self):
         class App(dm.BaseAppliance):
             x: int = 1
@@ -1974,22 +1966,6 @@ class MainTests(unittest.TestCase):
         with self.assertRaises(dm.ReadOnlyField):
             app.x = 99
 
-    def test_new_public_field_forbidden(self):
-        class App(dm.BaseAppliance):
-            x: int = 1
-
-        app = App()
-        with self.assertRaises(dm.NewFieldForbidden):
-            app.newfield = "oops"
-
-    def test_private_field_allowed_assignment(self):
-        class App(dm.BaseAppliance):
-            x: int = 1
-
-        app = App()
-        app._debug = "ok"
-        self.assertEqual(app._debug, "ok")
-
     def test_feature_override_does_not_leak_between_instances(self):
         class App(dm.BaseAppliance):
             class F1(dm.BaseFeature):
@@ -2071,31 +2047,6 @@ class MainTests(unittest.TestCase):
             class C(A, B):
                 pass
 
-    def test_wrong_feature_override(self):
-        class App(dm.BaseAppliance):
-            class F1(dm.BaseFeature):
-                val: int = 1
-
-        with self.assertRaises(dm.InvalidFieldValue):
-            App(F1={"doesnotexist": 123})
-
-    def test_nested_list_frozen(self):
-        class A(dm.BaseAppliance):
-            x: list[list[int]] = [[1, 2]]
-
-        a = A()
-        with self.assertRaises(AttributeError):
-            a.x[0].append(3)  # inner list should also be frozen
-
-    def test_feature_override_no_leakage(self):
-        class App(dm.BaseAppliance):
-            class F1(dm.BaseFeature):
-                val: int = 1
-
-        a1 = App(F1={"val": 99})
-        a2 = App()
-        self.assertEqual(a2.F1.val, 1)  # no leakage
-
     def test_initializer_can_use_math(self):
 
         class App(dm.BaseAppliance):
@@ -2110,6 +2061,426 @@ class MainTests(unittest.TestCase):
         # math.ceil(1.2)=2, math.floor(2.8)=2 → 4
         self.assertEqual(app.val, 4)
 
+    def test_deepfreeze_nested_mixed_tuple_list(self):
+        class App(dm.BaseAppliance):
+            data: tuple[list[int], tuple[int, list[int]]] = ([1, 2], (3, [4, 5]))
+
+        app = App()
+
+        # Top-level: must be tuple
+        self.assertIsInstance(app.data, tuple)
+
+        # First element of tuple: should have been frozen to tuple, not list
+        self.assertIsInstance(app.data[0], tuple)
+
+        # Nested second element: itself a tuple
+        self.assertIsInstance(app.data[1], tuple)
+
+        # Deepest element: inner list should also be frozen to tuple
+        self.assertIsInstance(app.data[1][1], tuple)
+
+        # Check immutability
+        with self.assertRaises(TypeError):
+            app.data[0] += (99,)  # tuples are immutable
+
+        with self.assertRaises(TypeError):
+            app.data[1][1] += (42,)  # inner tuple also immutable
+
+    def test_inacurate_type(self):
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance1(dm.BaseAppliance):
+                SomeVar: list = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance2(dm.BaseAppliance):
+                SomeVar: list[Any] = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance3(dm.BaseAppliance):
+                SomeVar: list[object] = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance4(dm.BaseAppliance):
+                SomeVar: dict = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance5(dm.BaseAppliance):
+                SomeVar: dict[str, Any] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance6(dm.BaseAppliance):
+                SomeVar: dict[Any, Any] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance7(dm.BaseAppliance):
+                SomeVar: dict[Any, str] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance8(dm.BaseAppliance):
+                SomeVar: dict[str, object] = {}
+
+    def test_deepfreeze_nested_dict_list_set(self):
+        class App(dm.BaseAppliance):
+            data: dict[str, list[int] | set[str] | dict[str, list[int] | set[str]]] = {
+                "numbers": [1, 2, 3],
+                "letters": {"a", "b", "c"},
+                "mixed": {"x": [4, 5], "y": {"z"}},
+            }
+
+        app = App()
+
+        # Top-level: should be frozendict
+        self.assertEqual(type(app.data).__name__, "frozendict")
+
+        # Lists must be frozen to tuple
+        self.assertIsInstance(app.data["numbers"], tuple)
+        self.assertIsInstance(app.data["mixed"]["x"], tuple)
+
+        # Sets must be frozen to frozenset
+        self.assertIsInstance(app.data["letters"], frozenset)
+        self.assertIsInstance(app.data["mixed"]["y"], frozenset)
+
+        # Check immutability
+        with self.assertRaises(TypeError):
+            app.data["numbers"] += (99,)
+
+        with self.assertRaises(AttributeError):
+            app.data["letters"].add("d")
+
+        with self.assertRaises(TypeError):
+            app.data["mixed"]["x"] += (6,)
+
+    def test_unknown_parameters_raise(self):
+        class App(dm.BaseAppliance):
+            a: int = 1
+
+        with self.assertRaises(dm.InvalidFieldValue) as cm:
+            App(foo=123)
+
+        self.assertIn("Unknown parameters:", str(cm.exception))
+        self.assertIn("foo", str(cm.exception))
+
+    def test_variadic_tuple_annotation_ok_and_errors(self):
+        class A(dm.BaseAppliance):
+            xs: tuple[int, ...] = (1, 2, 3)
+
+        self.assertEqual(A().xs, (1, 2, 3))
+
+        class B(dm.BaseAppliance):
+            xs: "Tuple[int, ...]" = (4, 5)
+
+        self.assertEqual(B().xs, (4, 5))
+
+        # wrong inner type should fail
+        with self.assertRaises(dm.InvalidFieldValue):
+
+            class _Bad(dm.BaseAppliance):
+                xs: tuple[int, ...] = (1, "x")
+
+    def test_field_override_typechecked_and_instance_local(self):
+        class App(dm.BaseAppliance):
+            a: list[int] = [1]
+
+        app1 = App(a=[9])
+        app2 = App()
+        # deepfreeze: lists become tuples
+        self.assertEqual(app1.a, (9,))
+        self.assertEqual(app2.a, (1,))  # no leakage
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(a=["oops"])  # wrong inner type
+
+    def test_runtime_attach_bound_feature_success(self):
+        class App(dm.BaseAppliance):
+            class F1(dm.BaseFeature):
+                val: int = 1
+
+        class Extra(App.F1):  # stays bound to App
+            val = 7
+
+        app = App(Extra=Extra)
+        self.assertTrue(hasattr(app, "Extra"))
+        self.assertIsInstance(app.Extra, Extra)
+        self.assertEqual(app.Extra.val, 7)
+
+    def test_cant_override_inherited_feature_annotation(self):
+        class App(dm.BaseAppliance):
+            class F1(dm.BaseFeature):
+                val: int = 1
+
+        with self.assertRaises(dm.ReadOnlyFieldAnnotation):
+
+            class Extra(App.F1):
+                val: str = "test"
+
+    def test_feature_fields_are_frozen_after_override(self):
+        class App(dm.BaseAppliance):
+            class F(dm.BaseFeature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        # dict override
+        app1 = App(F={"nums": [9], "tag": "y"})
+        self.assertEqual(app1.F.nums, (9,))
+        self.assertEqual(app1.F.tag, "y")
+        with self.assertRaises(AttributeError):
+            app1.F.nums.append(3)  # tuple
+
+        # subclass override
+        class F2(App.F):
+            nums = [4, 5]
+
+        app2 = App(F=F2)
+        self.assertEqual(app2.F.nums, (4, 5))
+        with self.assertRaises(dm.ReadOnlyField):
+            app2.F.nums += (6,)  # still immutable
+
+    def test_feature_dict_partial_override_keeps_other_defaults(self):
+        class App(dm.BaseAppliance):
+            class F(dm.BaseFeature):
+                a: int = 1
+                b: str = "k"
+
+        app = App(F={"b": "z"})
+        self.assertEqual(app.F.a, 1)  # default remains
+        self.assertEqual(app.F.b, "z")  # overridden
+
+    def test_root_field_override_nonexisting_rejected(self):
+        class App(dm.BaseAppliance):
+            x: int = 1
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(y=2)  # not in schema -> unknown parameter
+
+    def test_feature_override_linear_chain(self):
+        # Base appliance defines Feat1
+        class A(dm.BaseAppliance):
+            class Feat1(dm.BaseFeature):
+                x: int = 1
+
+        # ✅ Appliance B overrides Feat1 by subclassing A.Feat1
+        class B(A):
+            class Feat1(A.Feat1):
+                y: int = 2
+
+        self.assertTrue(issubclass(B.Feat1, A.Feat1))
+
+        # ✅ Appliance C overrides Feat1 again by subclassing B.Feat1 (not A.Feat1)
+        class C(B):
+            class Feat1(B.Feat1):
+                z: int = 3
+
+        self.assertTrue(issubclass(C.Feat1, B.Feat1))
+        self.assertTrue(issubclass(C.Feat1, A.Feat1))
+
+        # ❌ Bad: D tries to override with a *fresh* BaseFeature, not subclass of B.Feat1
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class D(B):
+                class Feat1(dm.BaseFeature):
+                    fail: str = "oops"
+
+        # ❌ Bad: E tries to override with ancestor (A.Feat1) instead of B.Feat1
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class E(B):
+                class Feat1(A.Feat1):
+                    fail: str = "oops"
+
+        # ✅ New feature name in child is always fine
+        class F(B):
+            class Feat2(dm.BaseFeature):
+                other: str = "ok"
+
+        self.assertTrue(hasattr(F, "Feat2"))
+
+    def test_feature_override_chain_runtime_replacement(self):
+        # Build a linear chain: A -> B -> C for feature 'Feat1'
+        class A(dm.BaseAppliance):
+            class Feat1(dm.BaseFeature):
+                x: int = 1
+
+        class B(A):
+            class Feat1(A.Feat1):
+                y: int = 2
+
+        class C(B):
+            class Feat1(B.Feat1):
+                z: int = 3
+
+        # ✅ OK: at instantiation of C, replacing Feat1 with a subclass of the LATEST (C.Feat1)
+        class CFeat1Plus(C.Feat1):
+            w: int = 4
+
+        c_ok = C(Feat1=CFeat1Plus)
+        self.assertIsInstance(c_ok.Feat1, CFeat1Plus)
+        self.assertEqual(
+            (c_ok.Feat1.x, c_ok.Feat1.y, c_ok.Feat1.z, c_ok.Feat1.w), (1, 2, 3, 4)
+        )
+
+        # ❌ Not OK: replacing with a subclass of the ancestor (A.Feat1) — must target latest (C.Feat1)
+        class AFeat1Alt(A.Feat1):
+            pass
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            C(Feat1=AFeat1Alt)
+
+        # ❌ Not OK: replacing with a subclass of the mid ancestor (B.Feat1) — still must target latest (C.Feat1)
+        class BFeat1Alt(B.Feat1):
+            pass
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            C(Feat1=BFeat1Alt)
+
+    def test_feature_inheritance_tree_and_no_leakage(self):
+        class A(dm.BaseAppliance):
+            class F1(dm.BaseFeature):
+                a: int = 1
+
+            class F2(dm.BaseFeature):
+                b: int = 2
+
+        # ✅ Child inherits both features automatically
+        class B(A):
+            c: str = "extra"
+
+        b1 = B()
+        self.assertIsInstance(b1.F1, A.F1)
+        self.assertIsInstance(b1.F2, A.F2)
+        self.assertEqual((b1.F1.a, b1.F2.b, b1.c), (1, 2, "extra"))
+
+        # ✅ Override only F2, F1 should still come from A
+        class C(B):
+            class F2(B.F2):
+                bb: int = 22
+
+        c1 = C()
+        self.assertIsInstance(c1.F1, A.F1)  # unchanged
+        self.assertIsInstance(c1.F2, C.F2)  # overridden
+        self.assertEqual((c1.F1.a, c1.F2.b, c1.F2.bb), (1, 2, 22))
+
+        # ✅ No leakage: instances of B are not affected by C's override
+        b2 = B()
+        self.assertIsInstance(b2.F2, A.F2)
+        self.assertFalse(hasattr(b2.F2, "bb"))
+
+        # ✅ Adding a new feature in D is independent of previous appliances
+        class D(C):
+            class F3(dm.BaseFeature):
+                d: int = 3
+
+        d1 = D()
+        self.assertIsInstance(d1.F1, A.F1)
+        self.assertIsInstance(d1.F2, C.F2)
+        self.assertIsInstance(d1.F3, D.F3)
+
+        # ✅ No leakage: instances of A and B should not see F3
+        a1 = A()
+        self.assertFalse(hasattr(a1, "F3"))
+        b3 = B()
+        self.assertFalse(hasattr(b3, "F3"))
+
+    def test_appliance_inheritance_tree_feature_isolation(self):
+        class A(dm.BaseAppliance):
+            class F1(dm.BaseFeature):
+                a: int = 1
+
+        # Branch 1 overrides F1
+        class B(A):
+            class F1(A.F1):
+                b: int = 2
+
+        # Branch 2 also overrides F1 differently
+        class C(A):
+            class F1(A.F1):
+                c: int = 3
+
+        # ✅ Instances of B use B.F1
+        b = B()
+        self.assertIsInstance(b.F1, B.F1)
+        self.assertEqual((b.F1.a, b.F1.b), (1, 2))
+        self.assertFalse(hasattr(b.F1, "c"))
+
+        # ✅ Instances of C use C.F1
+        c = C()
+        self.assertIsInstance(c.F1, C.F1)
+        self.assertEqual((c.F1.a, c.F1.c), (1, 3))
+        self.assertFalse(hasattr(c.F1, "b"))
+
+        # ✅ Base appliance A still uses its original feature
+        a = A()
+        self.assertIsInstance(a.F1, A.F1)
+        self.assertEqual(a.F1.a, 1)
+        self.assertFalse(hasattr(a.F1, "b"))
+        self.assertFalse(hasattr(a.F1, "c"))
+
+        # ✅ No leakage: B's override doesn't affect C and vice versa
+        b2 = B()
+        c2 = C()
+        self.assertTrue(hasattr(b2.F1, "b"))
+        self.assertFalse(hasattr(b2.F1, "c"))
+        self.assertTrue(hasattr(c2.F1, "c"))
+        self.assertFalse(hasattr(c2.F1, "b"))
+
+    def test_appliance_inheritance_tree_runtime_attach_isolation(self):
+        class A(dm.BaseAppliance):
+            class F1(dm.BaseFeature):
+                a: int = 1
+
+        class B(A):
+            class F1(A.F1):
+                b: int = 2
+
+        class C(A):
+            class F1(A.F1):
+                c: int = 3
+
+        # Define new runtime-attachable features
+        class FextraB(B.F1):
+            xb: int = 99
+
+        class FextraC(C.F1):
+            xc: int = -99
+
+        # ✅ Attach to B at instantiation
+        b = B(F1=FextraB)
+        self.assertIsInstance(b.F1, FextraB)
+        self.assertEqual((b.F1.a, b.F1.b, b.F1.xb), (1, 2, 99))
+        self.assertFalse(hasattr(b.F1, "c"))
+        self.assertFalse(hasattr(b.F1, "xc"))
+
+        # ✅ Attach to C at instantiation
+        c = C(F1=FextraC)
+        self.assertIsInstance(c.F1, FextraC)
+        self.assertEqual((c.F1.a, c.F1.c, c.F1.xc), (1, 3, -99))
+        self.assertFalse(hasattr(c.F1, "b"))
+        self.assertFalse(hasattr(c.F1, "xb"))
+
+        # ✅ Base appliance still untouched
+        a = A()
+        self.assertIsInstance(a.F1, A.F1)
+        self.assertEqual(a.F1.a, 1)
+        self.assertFalse(hasattr(a.F1, "b"))
+        self.assertFalse(hasattr(a.F1, "c"))
+        self.assertFalse(hasattr(a.F1, "xb"))
+        self.assertFalse(hasattr(a.F1, "xc"))
+
+        # ✅ Repeated instantiations stay isolated
+        b2 = B()
+        c2 = C()
+        self.assertIsInstance(b2.F1, B.F1)
+        self.assertIsInstance(c2.F1, C.F1)
+        self.assertFalse(hasattr(b2.F1, "xb"))
+        self.assertFalse(hasattr(c2.F1, "xc"))
+
 
 # ---------- main ----------