D&D 5E Magic Missile vs. Mirror Image

[jaelis]

I agree magic middle cannot target an image

However magic missile is a hit. Being a "hit" makes it an attack. No other spells are hits and so they are not attacks. All works fine here as well and makes sense. It's not about targeting. It's about hitting

I completely respect your reasoning, but do have to point out that nothing in the actual rules supports this. There is a specific discussion in the PHB about what constitutes an attack, and it does not mention hitting. Rather, it mentions an attack roll.

The PHB rule does, however, limit itself to situations where there is some question about whether an effect is an attack. So if in your mind there is no question that something which hits is an attack, then you are good to go. OTOH, since there is some question in my mind, the rules tell me that magic missile is not an attack. Thus we both get to be right by RAW

Furthermore JC's ruling is perfectly correct by RAW: the person wrote in to ask, therefore there was some question about it, therefore the PHB rule applies to them.