diff --git a/modules/default.nix b/modules/default.nix
index 61fd82d..6c344a1 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -95,6 +95,13 @@
         acceptTerms = true;
         email = "security@sbruder.de";
       };
+
+      system.activationScripts.diff = ''
+        [ -L /run/current-system ] && ${pkgs.nixUnstable}/bin/nix \
+            --experimental-features 'nix-command' \
+            store \
+            diff-closures /run/current-system "$systemConfig"
+      '';
     }
     (lib.mkIf (!config.sbruder.full) {
       # Adapted from nixpkgs/nixos/modules/profiles/minimal.nix