@@ -158,16 +158,16 @@ def spec_for_action(self, action):
             # I think the code below does it - but I'm not yet convinced it is working
             #TODO: add tests to validate this
             plugin = get_marshamallow_plugin(self.spec)
-            action_io_schema = build_action_schema(
-                action_output, 
-                action_input, 
-                base_class=Schema, 
-                name=f"{action.__name__}InputOutputSchema"
-            )
             action_schema = {
                 "allOf": [
                     plugin.resolver.resolve_schema_dict(ActionSchema),
-                    plugin.resolver.resolve_schema_dict(action_io_schema),
+                    {
+                        "type": "object",
+                        "parameters": {
+                            "input": plugin.resolver.resolve_schema_dict(action_input),
+                            "output": plugin.resolver.resolve_schema_dict(action_output),
+                        }
+                    }
                 ]
             }
             # The line below builds an ActionSchema subclass.  This works and
 
@@ -161,6 +161,7 @@ def build_action_schema(
     :param name: str:  (Default value = None)
 
     """
+    #FIXME: this seems to lose the schemas.  I suspect this is down to `nest_if_needed`.
     # Create a name for the generated schema
     if not name:
         name = str(id(output_schema))
 
@@ -64,3 +64,11 @@ def test_build_action_schema_typeerror():
     output_schema = object()
     with pytest.raises(TypeError):
         action_schema = schema.build_action_schema(input_schema, output_schema)
+
+def test_nest_if_needed():
+    nested_schema = schema.nest_if_needed(schema.ActionSchema())
+    assert isinstance(nested_schema, fields.Field)
+    nested_dict = schema.nest_if_needed({"name": fields.Integer()})
+    assert isinstance(nested_schema, fields.Field)
+    nested_field = schema.nest_if_needed(fields.Boolean())
+    assert isinstance(nested_schema, fields.Field)