I'm the DM of this game. During one of our games the party where fighting goblins and our Ranger said that he wanted to "Use his Action to Ready, and attack when the foe move". He meant move not in the mechanic way, but rather as soon as the goblin took any action whether that was moving or attacking. I said that he can't and that he should be more specific when declaring what triggers his reaction. This left me thinking.
The PHB isn't exactly clear but the examples it gives are for very specific triggers as in "if the cultist steps on the trapdoor..." or "if the goblin moves next to me...". Can our Ranger declare the Reaction the way he wanted and essentially take a delayed action? He is not getting any additional actions as the Ready is an action by itself and would be losing his reaction if he does take the trigger.
So how specific does a Ready trigger need to be?
