Currently trying to modify a StaffChat skript where when ever you did just /sc without text it give you a error message.
Skript:

options: scprefix:&8[&4StaffChat&8]&7
command /sc [<text>]:
trigger:
if player has permission "is.staff":
if arg-1 is set:
if arg-1 is "toggle":
if {sc.%player%} is "false":
set {sc.%player%} to "true"
send "{@scprefix} Staff chat enabled." to player
if {sc.%player%} is "true":
set {sc.%player%} to "false"
send "{@scprefix} Staff chat disabled." to player
else:
loop all players:
if loop-player has permission "is.staff":
send "{@scprefix} &c%player's display name%&f: &f%arg-1%" to loop-players

on chat:
if {sc.%player%} is "true":
loop all players:
if loop-player has permission "is.staff":
send "{@scprefix} &c%player's display name%&f: &f%message%"