diff --git a/contrib/sway/spatial.conf b/contrib/sway/spatial.conf
index d45f9cc..3d497f4 100644
--- a/contrib/sway/spatial.conf
+++ b/contrib/sway/spatial.conf
@@ -1,6 +1,7 @@
 # Before including this file, set the following
 # variables:
 #
+# set $mod
 # set $left
 # set $right
 # set $up