diff --git a/protocol/network/messages.md b/protocol/network/messages.md
index 7fc3dd7..67aa340 100644
--- a/protocol/network/messages.md
+++ b/protocol/network/messages.md
@@ -29,7 +29,7 @@ The `net magic` is designed to be unlikely to occur in normal data--the characte
 
 ### Command String
 
-The `command string` is a fixed-length 12 byte ASCII string.  The command string is used to determine the type of message being transmitted.  Messages with unknown an unrecognized `command string` are ignored.
+The `command string` is a fixed-length 12 byte ASCII string.  Commands may not be longer than 12 bytes.  Commands that are shorter than 12-bytes are right-padded with null bytes (`0x00`).  The command string is used to determine the type of message being transmitted.  Messages with an unrecognized `command string` are ignored.
 
 The following messages are considered standard by all node implementations.