Well. You could use VCE and the onItemPickup events, along with bot events. Might go sumthin like this:
SWORD BRICK EVENTS
onItemPickup - PlayerVCEMOD Var "GOTSWORD" set 1
BOT BRICK EVENTS
onBotDamaged - Player VCE IfVAR "GOTSWORD" = 1
onVarTrue - Client - ChatMsg - "U hit me with a sword, ouch!"
Just note that if you use any other weapon and hit them while still having the GOTSWORD var it will giv the same chat message. This is basically a work around seeing as how the events you are requesting do not exist.
You might be able to make it work better if you have the ifIteminHand or ifIteminInventory events. With those 2 events you could make it
onBotDamaged - Self/Player - IfItemInHand - Sword (i dont remember if its on player or on self)
onVarTrue - Client - Chat Msg - "U hit me with a sword, ouch!"
Hope this helps! PM me if you need further eventing assistance.