diff --git a/modules/server/containers/builder.nix b/modules/server/containers/builder.nix
index 5c1cd9c..0316723 100644
--- a/modules/server/containers/builder.nix
+++ b/modules/server/containers/builder.nix
@@ -33,7 +33,7 @@ let
   in lib.recursiveUpdate base overrides;
 in {
   mkContainer = builder;
-  mkData = { name, dir, var?{} }: pkgs.runCommand name vars ''
+  mkData = { name, dir, vars?{} }: pkgs.runCommand name vars ''
     export PATH="${pkgs.buildPackages.substituteAll}/bin:$PATH"
     mkdir -p $out
     cp -r ./data/${dir}/. $out/