diff --git a/home/fish.nix b/home/fish.nix
index 3dfe11b..10b286b 100644
--- a/home/fish.nix
+++ b/home/fish.nix
@@ -35,6 +35,10 @@
     mkdcd = {
       argumentNames = [ "target" ];
       body = ''
+        if test -z "$target"
+          echo "mkdcd requires an argument" 1>&2
+          return 1
+        end
         mkdir -p $target
         cd $target
       '';