diff --git a/metagpt/tools/functions/libs/udf/__init__.py b/metagpt/tools/functions/libs/udf/__init__.py
index add03f376..ad36b2817 100644
--- a/metagpt/tools/functions/libs/udf/__init__.py
+++ b/metagpt/tools/functions/libs/udf/__init__.py
@@ -114,4 +114,5 @@ function_signatures, function_returns = get_function_signatures_in_folder(folder
 UDFS = [func for func in function_signatures
         if not func['udf_name'].startswith(('extract_function_signatures', 'get_function_signatures_in_folder', 'docstring_to_yaml'))]
 
-UDFS_YAML = extract_function_schema_yaml_in_folder(folder_path)
+UDFS_YAML_STR: str = extract_function_schema_yaml_in_folder(folder_path)
+UDFS_YAML: dict = yaml.load(UDFS_YAML_STR, Loader=yaml.FullLoader)