[Toroi]

Hook the SendClientMessage function to (or make) a new function, check for the lenght of the string, if its more than the limit, cut it and send the rest in a separate SendClientMessage function

Tools you may need:
https://sampwiki.blast.hk/wiki/Function#Creating_and_Using
https://sampwiki.blast.hk/wiki/Control_Structures#if
https://sampwiki.blast.hk/wiki/Strlen
https://sampwiki.blast.hk/wiki/Strmid
https://sampwiki.blast.hk/wiki/SendClientMessage

Have fun.