Is it possible to ready an action to counterspell and then use it when a character uses a magic item instead of casting a spell, specifically using dispel magic? I haven't been able to find anything that would address this clearly. I suppose that I might be able to see this as being possible if a character was using a spell completion item or a spell trigger item since it is fairly clear to someone watching that they are using an item to cast a spell. However, the debate that caused this question relates to a command word activated item. In this case it is a pair of boots that cast dimension door when the command word is spoken. My GM asserts that if someone had readied an action to counterspell the character, if the character activated the boots the person with the readied action could then try to counter dimension door using dispel magic. As Ive said I can't find anything that specifically addresses this, but it seems very silly to me. Lets say for the sake of the argument the command word for the boots is 'pickles.' How could someone, even someone who is watching the character closely, possibly figure out 'He said pickles. I must quickly cast my readied spell before his boots activate.' Any insight would be appreciated.