diff --git a/Lib/test/test_except_star_aug.py b/Lib/test/test_except_star_aug.py
new file mode 100644
index 0000000000..94ec8aaea3
--- /dev/null
+++ b/Lib/test/test_except_star_aug.py
@@ -0,0 +1,508 @@
+import ast
+import unittest
+
+
+def leaf_types(exc):
+    leaves = []
+    if isinstance(exc, BaseExceptionGroup):
+        for nested in exc.exceptions:
+            leaves.extend(leaf_types(nested))
+    else:
+        leaves.append(type(exc))
+    return leaves
+
+
+class ExceptionGroupAugTest(unittest.TestCase):
+    def test_ast_unparse_opcode_and_validation_surface(self):
+        source = (
+            "try:\n"
+            "    pass\n"
+            "except* ValueError as exc:\n"
+            "    pass\n"
+            "finally:\n"
+            "    pass\n"
+        )
+        tree = ast.parse(source)
+        self.assertIsInstance(tree.body[0], ast.TryStar)
+        rendered = ast.unparse(tree)
+        self.assertIn("except* ValueError as exc", rendered)
+        self.assertNotIn("except ValueError as exc", rendered)
+
+        invalid = ast.Module(
+            body=[ast.TryStar(body=[ast.Pass()], handlers=[], orelse=[], finalbody=[])],
+            type_ignores=[],
+        )
+        ast.fix_missing_locations(invalid)
+        with self.assertRaises(ValueError):
+            compile(invalid, "<invalid-trystar>", "exec")
+
+    def test_subgroup_and_split_partitioning_contracts(self):
+        group = ExceptionGroup(
+            "root",
+            [
+                ValueError("v1"),
+                ExceptionGroup("nested", [TypeError("t"), ValueError("v2")]),
+                OSError("os"),
+            ],
+        )
+        subgroup = group.subgroup(lambda exc: isinstance(exc, ValueError))
+        self.assertEqual(leaf_types(subgroup), [ValueError, ValueError])
+
+        with self.assertRaises(TypeError):
+            group.split((ValueError, 42))
+
+        match, rest = ExceptionGroup("pair", [ValueError("v"), TypeError("t")]).split(ValueError)
+        self.assertEqual(leaf_types(match), [ValueError])
+        self.assertEqual(leaf_types(rest), [TypeError])
+
+        derive_calls = []
+
+        class TrackingGroup(ExceptionGroup):
+            def derive(self, excs):
+                derive_calls.append(tuple(type(exc) for exc in excs))
+                return type(self)(self.message, excs)
+
+        tracked = TrackingGroup("tracked", [ValueError("v"), TypeError("t")])
+        self.assertEqual(leaf_types(tracked.subgroup(ValueError)), [ValueError])
+        self.assertEqual(derive_calls, [(ValueError,)])
+
+    def test_except_star_matching_wrapping_and_forbidden_handlers(self):
+        caught = []
+        try:
+            raise ExceptionGroup("eg", [ValueError("v")])
+        except* Exception as eg:
+            caught.append(eg)
+        self.assertEqual(caught[0].message, "eg")
+        self.assertEqual(leaf_types(caught[0]), [ValueError])
+        self.assertIsInstance(caught[0].exceptions[0], ValueError)
+
+        naked = []
+        try:
+            raise ValueError("naked")
+        except* ValueError as eg:
+            naked.append(eg)
+        self.assertIsInstance(naked[0], ExceptionGroup)
+        self.assertEqual(leaf_types(naked[0]), [ValueError])
+
+        with self.assertRaises(TypeError):
+            try:
+                raise ExceptionGroup("eg", [ValueError("v")])
+            except* ExceptionGroup:
+                pass
+
+    def test_except_star_reraise_and_unmatched_rest(self):
+        seen = []
+        try:
+            raise ExceptionGroup(
+                "root",
+                [ExceptionGroup("inner", [ValueError("v"), TypeError("t")])],
+            )
+        except* ValueError as eg:
+            seen.append(leaf_types(eg))
+        except* TypeError as eg:
+            seen.append(leaf_types(eg))
+        self.assertEqual(seen, [[ValueError], [TypeError]])
+
+        with self.assertRaises(ExceptionGroup) as raised:
+            try:
+                raise ValueError("naked")
+            except* ValueError:
+                raise
+        self.assertEqual(leaf_types(raised.exception), [ValueError])
+
+        handled = []
+        try:
+            try:
+                raise ExceptionGroup("eg", [ValueError("v"), TypeError("t")])
+            except* ValueError as eg:
+                handled.append(leaf_types(eg))
+        except ExceptionGroup as rest:
+            self.assertEqual(handled, [[ValueError]])
+            self.assertEqual(leaf_types(rest), [TypeError])
+        else:
+            self.fail("unmatched TypeError subgroup was not reraised")
+
+        try:
+            try:
+                raise ExceptionGroup("eg", [ValueError("v"), TypeError("t")])
+            except* ValueError:
+                raise
+        except ExceptionGroup as reraised:
+            self.assertEqual(leaf_types(reraised), [ValueError, TypeError])
+        else:
+            self.fail("bare reraise and unmatched rest were not combined")
+
+    def test_except_star_new_exceptions_finally_else_and_routing(self):
+        marker = []
+        try:
+            try:
+                raise ExceptionGroup("eg", [ValueError("v")])
+            except* ValueError:
+                marker.append("handled")
+            finally:
+                marker.append("finally")
+        except ExceptionGroup:
+            self.fail("all sub-exceptions should be handled")
+        self.assertEqual(marker, ["handled", "finally"])
+
+        else_marker = []
+        try:
+            else_marker.append("try")
+        except* ValueError:
+            else_marker.append("handler")
+        else:
+            else_marker.append("else")
+        self.assertEqual(else_marker, ["try", "else"])
+
+        with self.assertRaises(ExceptionGroup) as cm:
+            try:
+                raise ExceptionGroup("eg", [ValueError("v")])
+            except* ValueError:
+                raise TypeError("new")
+        self.assertEqual(leaf_types(cm.exception), [TypeError])
+
+        routed = []
+        try:
+            raise ExceptionGroup("eg", [ValueError("v"), TypeError("t")])
+        except* ValueError as eg:
+            routed.append(("value", leaf_types(eg)))
+        except* TypeError as eg:
+            routed.append(("type", leaf_types(eg)))
+        self.assertEqual(routed, [("value", [ValueError]), ("type", [TypeError])])
+
+    def test_forbidden_control_flow_in_except_star_blocks(self):
+        cases = [
+            "for item in [1]:\n"
+            "    try:\n"
+            "        raise ExceptionGroup('eg', [ValueError()])\n"
+            "    except* ValueError:\n"
+            "        break\n",
+            "for item in [1]:\n"
+            "    try:\n"
+            "        raise ExceptionGroup('eg', [ValueError()])\n"
+            "    except* ValueError:\n"
+            "        continue\n",
+            "def f():\n"
+            "    try:\n"
+            "        raise ExceptionGroup('eg', [ValueError()])\n"
+            "    except* ValueError:\n"
+            "        return 1\n",
+        ]
+        for source in cases:
+            with self.subTest(source=source):
+                with self.assertRaises(SyntaxError):
+                    compile(source, "<forbidden-except-star>", "exec")
+
+    def test_exception_group_constructor_and_metadata_edges(self):
+        with self.assertRaises(ValueError):
+            ExceptionGroup("empty", [])
+        with self.assertRaises(ValueError):
+            ExceptionGroup("bad", [ValueError("v"), object()])
+
+        class Fatal(BaseException):
+            pass
+
+        with self.assertRaises(TypeError):
+            ExceptionGroup("bad-base", [Fatal("fatal")])
+
+        base = BaseExceptionGroup("base", [Fatal("fatal")])
+        self.assertIs(type(base), BaseExceptionGroup)
+        auto = BaseExceptionGroup("auto", [ValueError("v")])
+        self.assertIs(type(auto), ExceptionGroup)
+
+        group = ExceptionGroup("root", [ValueError("v"), TypeError("t")])
+        self.assertEqual(group.message, "root")
+        self.assertEqual(tuple(type(exc) for exc in group.exceptions), (ValueError, TypeError))
+        self.assertIsNone(group.subgroup(KeyError))
+
+        match, rest = group.split((ValueError, TypeError))
+        self.assertEqual(leaf_types(match), [ValueError, TypeError])
+        self.assertIsNone(rest)
+
+        match, rest = group.split(KeyError)
+        self.assertIsNone(match)
+        self.assertEqual(leaf_types(rest), [ValueError, TypeError])
+
+        seen = []
+        self.assertIsNone(group.subgroup(lambda exc: seen.append(type(exc)) or False))
+        self.assertEqual(seen, [ExceptionGroup, ValueError, TypeError])
+
+        try:
+            try:
+                raise OSError("cause")
+            except OSError as cause:
+                raise ExceptionGroup("eg", [TypeError("leaf")]) from cause
+        except ExceptionGroup as eg:
+            clone = eg.subgroup(TypeError)
+            self.assertIs(clone.__cause__, eg.__cause__)
+            self.assertIs(clone.__context__, eg.__context__)
+            self.assertTrue(clone.__suppress_context__)
+            self.assertEqual(leaf_types(clone), [TypeError])
+
+    def test_except_star_runtime_and_compile_matrix(self):
+        cases = [
+            (
+                "tuple_match_else_finally",
+                """
+events = []
+try:
+    raise ExceptionGroup('eg', [ValueError('v'), TypeError('t')])
+except* (ValueError, TypeError) as eg:
+    events.append(('caught', [type(e).__name__ for e in eg.exceptions]))
+else:
+    events.append(('else', []))
+finally:
+    events.append(('finally', []))
+""",
+                [("caught", ["ValueError", "TypeError"]), ("finally", [])],
+            ),
+            (
+                "unmatched_rest_then_outer_group",
+                """
+events = []
+try:
+    try:
+        raise ExceptionGroup('eg', [ValueError('v'), LookupError('l')])
+    except* ValueError as eg:
+        events.append(('value', [type(e).__name__ for e in eg.exceptions]))
+except ExceptionGroup as rest:
+    events.append(('rest', [type(e).__name__ for e in rest.exceptions]))
+""",
+                [("value", ["ValueError"]), ("rest", ["LookupError"])],
+            ),
+            (
+                "new_exceptions_from_two_handlers",
+                """
+events = []
+try:
+    try:
+        raise ExceptionGroup('eg', [ValueError('v'), TypeError('t')])
+    except* ValueError:
+        raise RuntimeError('new-v')
+    except* TypeError:
+        raise OSError('new-t')
+except ExceptionGroup as raised:
+    events = [type(e).__name__ for e in raised.exceptions]
+""",
+                ["RuntimeError", "OSError"],
+            ),
+            (
+                "valid_nested_control_flow",
+                """
+events = []
+try:
+    raise ExceptionGroup('eg', [ValueError('v')])
+except* ValueError:
+    for i in range(2):
+        if i:
+            break
+        events.append(i)
+""",
+                [0],
+            ),
+            (
+                "function_return_after_except_star",
+                """
+def f():
+    try:
+        raise ExceptionGroup('eg', [ValueError('v')])
+    except* ValueError:
+        marker = 'handled'
+    return marker
+events = f()
+""",
+                "handled",
+            ),
+        ]
+        globals_ = {
+            "ExceptionGroup": ExceptionGroup,
+            "LookupError": LookupError,
+            "OSError": OSError,
+            "RuntimeError": RuntimeError,
+            "TypeError": TypeError,
+            "ValueError": ValueError,
+            "range": range,
+            "type": type,
+        }
+        for name, source, expected in cases:
+            with self.subTest(name=name):
+                code = compile(source, f"<{name}>", "exec")
+                ns = {}
+                exec(code, globals_, ns)
+                self.assertEqual(ns["events"], expected)
+
+        invalid_sources = [
+            "try:\n    pass\nexcept ValueError:\n    pass\nexcept* TypeError:\n    pass\n",
+            "try:\n    pass\nexcept*:\n    pass\n",
+            "try:\n    pass\nexcept* ValueError as exc, TypeError:\n    pass\n",
+            "try:\n    pass\nexcept* (ValueError,):\n    pass\nexcept TypeError:\n    pass\n",
+        ]
+        for source in invalid_sources:
+            with self.subTest(source=source):
+                with self.assertRaises(SyntaxError):
+                    compile(source, "<invalid-except-star>", "exec")
+
+    def test_try_star_ast_manual_construction_roundtrip(self):
+        handler = ast.ExceptHandler(
+            type=ast.Name(id="ValueError", ctx=ast.Load()),
+            name="exc",
+            body=[
+                ast.Assign(
+                    targets=[ast.Name(id="handled", ctx=ast.Store())],
+                    value=ast.Call(
+                        func=ast.Name(id="isinstance", ctx=ast.Load()),
+                        args=[
+                            ast.Name(id="exc", ctx=ast.Load()),
+                            ast.Name(id="ExceptionGroup", ctx=ast.Load()),
+                        ],
+                        keywords=[],
+                    ),
+                )
+            ],
+        )
+        tree = ast.Module(
+            body=[
+                ast.Assign(
+                    targets=[ast.Name(id="handled", ctx=ast.Store())],
+                    value=ast.Constant(value=None),
+                ),
+                ast.TryStar(
+                    body=[
+                        ast.Raise(
+                            exc=ast.Call(
+                                func=ast.Name(id="ValueError", ctx=ast.Load()),
+                                args=[ast.Constant(value="manual")],
+                                keywords=[],
+                            ),
+                            cause=None,
+                        )
+                    ],
+                    handlers=[handler],
+                    orelse=[
+                        ast.Assign(
+                            targets=[ast.Name(id="handled", ctx=ast.Store())],
+                            value=ast.Constant(value="else"),
+                        )
+                    ],
+                    finalbody=[
+                        ast.Assign(
+                            targets=[ast.Name(id="done", ctx=ast.Store())],
+                            value=ast.Constant(value=True),
+                        )
+                    ],
+                ),
+            ],
+            type_ignores=[],
+        )
+        ast.fix_missing_locations(tree)
+        ns = {}
+        exec(
+            compile(tree, "<manual-trystar>", "exec"),
+            {"ExceptionGroup": ExceptionGroup, "ValueError": ValueError, "isinstance": isinstance},
+            ns,
+        )
+        self.assertIs(ns["handled"], True)
+        self.assertIs(ns["done"], True)
+
+        rendered = ast.unparse(tree)
+        self.assertIn("except* ValueError as exc", rendered)
+        reparsed = ast.parse(rendered)
+        self.assertIsInstance(reparsed.body[1], ast.TryStar)
+
+        bad_handler = ast.Module(
+            body=[
+                ast.TryStar(
+                    body=[ast.Pass()],
+                    handlers=[ast.Pass()],
+                    orelse=[],
+                    finalbody=[],
+                )
+            ],
+            type_ignores=[],
+        )
+        ast.fix_missing_locations(bad_handler)
+        with self.assertRaises(TypeError):
+            compile(bad_handler, "<bad-trystar-handler>", "exec")
+
+    def test_except_star_error_cleanup_and_reraise_edges(self):
+        def handler_name_is_cleared():
+            try:
+                raise ExceptionGroup("eg", [ValueError("v")])
+            except* ValueError as exc:
+                saved = exc
+            return "exc" in locals(), leaf_types(saved)
+
+        self.assertEqual(handler_name_is_cleared(), (False, [ValueError]))
+
+        def handler_name_is_cleared_when_body_raises():
+            try:
+                try:
+                    raise ExceptionGroup("eg", [ValueError("v")])
+                except* ValueError as exc:
+                    saved = exc
+                    raise RuntimeError("new")
+            except ExceptionGroup as raised:
+                return "exc" in locals(), leaf_types(saved), leaf_types(raised)
+
+        self.assertEqual(
+            handler_name_is_cleared_when_body_raises(),
+            (False, [ValueError], [RuntimeError]),
+        )
+
+        with self.assertRaises(ValueError):
+            try:
+                raise ValueError("plain")
+            except* TypeError:
+                pass
+
+        with self.assertRaises(ExceptionGroup) as mixed:
+            try:
+                raise ExceptionGroup("eg", [ValueError("v"), TypeError("t")])
+            except* ValueError:
+                raise
+            except* TypeError:
+                raise RuntimeError("replacement")
+        self.assertEqual(leaf_types(mixed.exception), [RuntimeError, ValueError])
+
+        invalid_runtime_handlers = [
+            "object",
+            "(ValueError, object)",
+            "(ValueError, ExceptionGroup)",
+            "BaseExceptionGroup",
+        ]
+        for handler in invalid_runtime_handlers:
+            source = (
+                "try:\n"
+                "    raise ExceptionGroup('eg', [ValueError('v')])\n"
+                f"except* {handler}:\n"
+                "    pass\n"
+            )
+            with self.subTest(handler=handler):
+                with self.assertRaises(TypeError):
+                    exec(source, {"ExceptionGroup": ExceptionGroup, "ValueError": ValueError})
+
+        annotated_sources = [
+            "try:\n"
+            "    x: int = 1\n"
+            "except* ValueError:\n"
+            "    pass\n",
+            "try:\n"
+            "    pass\n"
+            "except* ValueError:\n"
+            "    y: int = 2\n"
+            "else:\n"
+            "    z: int = 3\n",
+            "try:\n"
+            "    pass\n"
+            "except* ValueError:\n"
+            "    pass\n"
+            "finally:\n"
+            "    w: int = 4\n",
+        ]
+        for source in annotated_sources:
+            with self.subTest(source=source):
+                compile(source, "<annotated-trystar>", "exec")
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/Lib/test/test_exception_stability_aug.py b/Lib/test/test_exception_stability_aug.py
new file mode 100644
index 0000000000..f4f9c09132
--- /dev/null
+++ b/Lib/test/test_exception_stability_aug.py
@@ -0,0 +1,54 @@
+import ast
+import sys
+import unittest
+
+
+class ExceptionStabilityAugTest(unittest.TestCase):
+    def test_regular_try_except_else_finally_order_is_unchanged(self):
+        events = []
+        try:
+            events.append("try")
+        except ValueError:
+            events.append("except")
+        else:
+            events.append("else")
+        finally:
+            events.append("finally")
+
+        self.assertEqual(events, ["try", "else", "finally"])
+
+    def test_regular_exception_chaining_and_context_are_unchanged(self):
+        try:
+            try:
+                raise KeyError("inner")
+            except KeyError as exc:
+                raise RuntimeError("outer") from exc
+        except RuntimeError as exc:
+            self.assertIsInstance(exc.__cause__, KeyError)
+            self.assertIs(exc.__context__, exc.__cause__)
+            self.assertTrue(exc.__suppress_context__)
+
+    def test_ast_unparse_regular_try_uses_except_keyword(self):
+        source = (
+            "try:\n"
+            "    raise ValueError('x')\n"
+            "except ValueError as exc:\n"
+            "    handled = str(exc)\n"
+        )
+        tree = ast.parse(source)
+        self.assertEqual(type(tree.body[0]).__name__, "Try")
+        rendered = ast.unparse(tree)
+        self.assertIn("except ValueError as exc", rendered)
+        self.assertNotIn("except* ValueError as exc", rendered)
+
+    def test_sys_exc_info_restores_after_handled_exception(self):
+        before = sys.exc_info()
+        try:
+            raise ValueError("handled")
+        except ValueError:
+            self.assertIs(sys.exc_info()[0], ValueError)
+        self.assertEqual(sys.exc_info(), before)
+
+
+if __name__ == "__main__":
+    unittest.main()