diff --git a/temporalio/workflow.py b/temporalio/workflow.py
index a650ebd1..ed96324a 100644
--- a/temporalio/workflow.py
+++ b/temporalio/workflow.py
@@ -1478,6 +1478,16 @@ def _get_init_fn_takes_workflow_input(
     elif set(init_params) == {"self"}:
         # User __init__ with (self) signature
         return False, None
+    else:
+        # This (in 3.12) differs from the default signature inherited from
+        # object.__init__, which is (self, /, *args, **kwargs). We allow both as
+        # valid __init__ signatures (that do not take workflow input).
+        class StarArgsStarStarKwargs:
+            def __init__(self, *args, **kwargs) -> None:
+                pass
+
+        if init_params == inspect.signature(StarArgsStarStarKwargs.__init__).parameters:
+            return False, None
 
     init_param_types, _ = temporalio.common._type_hints_from_func(init_fn)
     run_param_types, _ = temporalio.common._type_hints_from_func(run_fn)
diff --git a/tests/test_workflow.py b/tests/test_workflow.py
index 2082d7df..9d32e6f8 100644
--- a/tests/test_workflow.py
+++ b/tests/test_workflow.py
@@ -393,10 +393,7 @@ async def run(self, arg: MyDataClass) -> None:
         pass
 
 
-class WorkflowInitGoodSlashStarArgsStarStarKwargsInitZeroParamRun:
-    # TODO: if they include the slash it will be allowed as it is
-    # indistinguishable from the default __init__ inherited from object. But if
-    # they don't it will not be.
+class WorkflowInitGoodSlashStarArgsStarStarKwargs:
     def __init__(self, /, *args, **kwargs) -> None:
         pass
 
@@ -405,6 +402,15 @@ async def run(self) -> None:
         pass
 
 
+class WorkflowInitGoodStarArgsStarStarKwargs:
+    def __init__(self, *args, **kwargs) -> None:
+        pass
+
+    @workflow.run
+    async def run(self) -> None:
+        pass
+
+
 @pytest.mark.parametrize(
     "cls",
     [
@@ -413,7 +419,8 @@ async def run(self) -> None:
         WorkflowInitGoodNoArgInitZeroParamRun,
         WorkflowInitGoodNoArgInitOneParamRun,
         DataClassTypedWorkflowProto,
-        WorkflowInitGoodSlashStarArgsStarStarKwargsInitZeroParamRun,
+        WorkflowInitGoodSlashStarArgsStarStarKwargs,
+        WorkflowInitGoodStarArgsStarStarKwargs,
     ],
 )
 def test_workflow_init_good_does_not_take_workflow_input(cls):
@@ -503,18 +510,6 @@ def test_workflow_init_good_takes_workflow_input(cls):
     ).__temporal_workflow_definition.init_fn_takes_workflow_input
 
 
-class WorkflowInitBadStarArgsStarStarKwargs:
-    # TODO: if they include the slash it will be allowed as it is
-    # indistinguishable from the default __init__ inherited from object. But if
-    # they don't it will not be.
-    def __init__(self, *args, **kwargs) -> None:
-        pass
-
-    @workflow.run
-    async def run(self) -> None:
-        pass
-
-
 class WorkflowInitBadExtraInitParamUntyped:
     def __init__(self, a) -> None:
         pass
@@ -554,7 +549,6 @@ async def run(self, aa: int, bb: str) -> None:
 @pytest.mark.parametrize(
     "cls",
     [
-        WorkflowInitBadStarArgsStarStarKwargs,
         WorkflowInitBadExtraInitParamUntyped,
         WorkflowInitBadMismatchedParamUntyped,
         WorkflowInitBadExtraInitParamTyped,