diff --git a/flake.nix b/flake.nix
index 58bf9ae..97439a5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -45,6 +45,9 @@
             pkgs.pyewjnEnv
             pkgs.pyewjn
           ];
+          shellHook = ''
+            export DO_NIX_CUSTOM=1
+          '';
         };
 
       }));