diff --git a/validator.py b/validator.py
old mode 100644
new mode 100755
index 6b914c9..c4cb129
--- a/validator.py
+++ b/validator.py
@@ -1,3 +1,6 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i python3 -p python3 tcsh
+
 from __future__ import annotations
 from dataclasses import dataclass