diff --git a/config/comms.txt b/config/comms.txt
index ae336d484b6..421a7c6dd98 100644
--- a/config/comms.txt
+++ b/config/comms.txt
@@ -1,4 +1,5 @@
-## Communication key for receiving data through world/Topic(), you don't want to give this out
+## Communication key for receiving data through world/Topic(), you don't want to give this out.
+## Must be set to something other than 'default_pwd' and at least 7 characters long to be valid.
 #COMMS_KEY default_pwd
 
 ## World address and port for server receiving cross server messages