diff --git a/scripts/mbedtls_dev/test_generation.py b/scripts/mbedtls_dev/test_generation.py
index d5d7e5f..5de0b88 100644
--- a/scripts/mbedtls_dev/test_generation.py
+++ b/scripts/mbedtls_dev/test_generation.py
@@ -178,9 +178,9 @@
         test_cases = self.targets[name](*target_args)
         self.write_test_data_file(name, test_cases)
 
-def main(args, generator_class: Type[TestGenerator] = TestGenerator):
+def main(args, description: str, generator_class: Type[TestGenerator] = TestGenerator):
     """Command line entry point."""
-    parser = argparse.ArgumentParser(description=__doc__)
+    parser = argparse.ArgumentParser(description=description)
     parser.add_argument('--list', action='store_true',
                         help='List available targets and exit')
     parser.add_argument('targets', nargs='*', metavar='TARGET',