fix: preserve nullability in null-only anyOf and fix validate param alias

Merge PR #3173 as the preferred fix for the null-only anyOf schema behavior and validate alias handling.

python/composio/utils/schema_converter.py

@@ -234,6 +234,8 @@ def _handle_toplevel_combiner(
             allow_undefined_array_items=True,
             allow_undefined_type=True,
         )
+        if result is type(None):
+            return t.Optional[t.Any]
         # If result is a type (like a Union or Optional), return it directly
         # If result is a model class, return it
         return result
@@ -270,7 +272,7 @@ def _build_union_from_options(options: t.List[t.Dict[str, t.Any]]) -> t.Type:
         pydantic_types.append(ptype)
 
     if len(pydantic_types) == 0:
-        return str  # Fallback
+        return t.Optional[t.Any] if has_null else str
 
     if len(pydantic_types) == 1:
         base_type = pydantic_types[0]

python/composio/utils/shared.py

@@ -210,9 +210,10 @@ def json_schema_to_pydantic_field(
         default = _coerce_default_value(default, json_schema)
 
     # Check if the field name is a reserved Pydantic name
+    original_name = name
     if name in reserved_names:
         name = f"{name}_"
-        alias = name
+        alias = original_name
     else:
         alias = None
 
@@ -222,7 +223,7 @@ def json_schema_to_pydantic_field(
         "alias": alias,
     }
     if not skip_default:
-        field["default"] = ... if name in required else default
+        field["default"] = ... if original_name in required else default
 
     return (
         name,

python/tests/test_schema_parser.py

@@ -121,7 +121,26 @@ class TestJsonSchemaToPydanticField:
         )
 
         assert field_name == "validate_"  # Should be renamed
-        assert field_info.alias == "validate_"  # Should have alias
+        assert field_info.alias == "validate"  # Should preserve original name
+
+    def test_reserved_required_field_name_preserves_required_status(self):
+        """Test that reserved field names keep the original alias and required status."""
+        name = "validate"
+        json_schema = {
+            "type": "string",
+            "description": "A required field with reserved name",
+            "title": "Validate",
+        }
+        required = ["validate"]
+
+        field_name, field_type, field_info = json_schema_to_pydantic_field(
+            name, json_schema, required
+        )
+
+        assert field_name == "validate_"
+        assert field_type is str
+        assert field_info.alias == "validate"
+        assert field_info.default is PydanticUndefined
 
     def test_field_with_examples(self):
         """Test that examples are properly preserved in field info."""
@@ -394,6 +413,14 @@ class TestJsonSchemaToPydanticType:
             result = json_schema_to_pydantic_type(json_schema)
             assert result == expected_type
 
+    def test_anyof_null_only_preserves_nullability(self):
+        """Test that anyOf with only null maps to Optional[Any] instead of str."""
+        result = json_schema_to_pydantic_type({"anyOf": [{"type": "null"}]})
+
+        assert t.get_origin(result) is t.Union
+        assert t.Any in t.get_args(result)
+        assert type(None) in t.get_args(result)
+
     def test_array_type(self):
         """Test array type conversion."""
         json_schema = {"type": "array", "items": {"type": "string"}}