diff --git a/nixos/modules/services/x11/window-managers/xmonad.nix b/nixos/modules/services/x11/window-managers/xmonad.nix
index e25a8ae22823..43de746ab1f1 100644
--- a/nixos/modules/services/x11/window-managers/xmonad.nix
+++ b/nixos/modules/services/x11/window-managers/xmonad.nix
@@ -29,6 +29,7 @@ in
 
       extraPackages = mkOption {
         default = self: [];
+        defaultText = "self: []";
         example = literalExample ''
           haskellPackages: [
             haskellPackages.xmonad-contrib