heirodule
First Post
The latest Sage Advice Online answers the question this way
Or does this
But isn't the Alarm spell the sensing trigger for a great variety of traps? If the rogue has to walk right past the alarm trigger to get to the meat of the trap to disable it, it's impossible to disable the trap!No and no.
Unfortunately, the rules don’t clearly define a category of spells that qualify as traps, so we must rely on individual spell descriptions to adjudicate this question.
Despite the alarm spell’s similarity to glyph of warding -- they’re both long-lasting defensive spells used to protect an area -- the spell description for alarm doesn’t contain any details about how to disable it, nor is it listed in the Disable Device skill description as a spell that creates a disarmable trap (PHB, pg. 72). Thus, we must conclude that the alarm spell should not be treated as a trap and cannot be disarmed with Disable Device.
Or does this
mean that you should never have a case where the alarm on the mcguffin sets off the lightning bolt when someone approaches within 20 feet?The proximity trigger used most often for magic device traps is the alarm spell. Unlike when the spell is cast, an alarm spell used as a trigger can have an area that’s no larger than the area the trap is meant to protect.