Hiding and sneaking past triggers

[hyphz]

Per page 305, it is possible to hide from a spell's trigger that uses visual detection, and a "Stealth check to Sneak" can fool an auditory sensor.

This begs a ton of questions, I'm afraid:

* Does this apply only to spells, or to any triggered effect - in particular, Readied actions?

* When "Sneaking" to fool an auditory sensor, does this refer to the usual Sneak performed as part of a move action, or is it a special case of Sneaking used to specifically hide ambient sound (eg, breathing) that might trigger the spell?

* The spell "Alarm" refers to detecting creatures in the area, but does not have the Auditory or Visual traits nor describe this as a trigger. Does this mean it cannot be snuck past? Are characters aware of which spells this applies to?

[Claxon]

Well for a character to take a Readied Action against you, they'd have to be aware of you, so it seems pretty straightforward that yeah, using Stealth successful against an enemy to hide would prevent them from using a readied action, at least until you stop being hidden (and they may ready an action to do something when you stop being hidden, like after an attack).

[Taja the Barbarian]

Chapter 7: Spells / Setting Triggers wrote:

Source Core Rulebook pg. 305

If a spell is meant to respond only to certain events or under certain conditions—such as magic mouth—it might require you to set a trigger. This is a simple sensory cue that causes the spell to activate. The spell activates as a reaction when the spell’s sensor observes something that fits its trigger. Depending on the spell, the trigger might be the presence of a type of creature, such as “red-haired dwarven women,” or it could be an observed action, such as “whenever someone enters the spell’s area.”

Disguises and illusions fool the spell as long as they appear to match its parameters. For a spell to detect something visually, the spell’s origin point must have line of sight. Darkness doesn’t prevent this, but invisibility does, as does a successful Stealth check to Hide (against the spell’s DC). For auditory detection, line of sight isn’t necessary, though the sound must be audible at the spell’s origin point. A Stealth check to Sneak can fool the sensor.

This specific rule is for Spells.

Readied Actions are similarly dependent on a specific trigger, so a successful Sneak check could nullify it since the successful 'sneaker' is Undetected:

Conditions / Undetected wrote:

Source Core Rulebook pg. 623

When you are undetected by a creature, that creature cannot see you at all, has no idea what space you occupy, and can’t target you, though you still can be affected by abilities that target an area. When you’re undetected by a creature, that creature is flat-footed to you.

A creature you’re undetected by can guess which square you’re in to try targeting you. It must pick a square and attempt an attack. This works like targeting a hidden creature (requiring a DC 11 flat check), but the flat check and attack roll are rolled in secret by the GM, who doesn’t reveal whether the attack missed due to failing the flat check, failing the attack roll, or choosing the wrong square.

A creature can use the Seek action to try to find you.

Just note that making a sneak check generally requires you to have cover or concealment at the end of your movement (you literally don't even get to roll your check if you don't), although there are ways around this.

[hyphz]

The trick is that Sneak is usually used for movement, but the text on spells doesn't say the trigger has to relate to movement. It just says that a Sneak check fools an Auditory sensor, which isn't how the move works at any other time.

Also, is there any answer on Alarm? It seems a bit problematic otherwise, because although Alarm might not be that dangerous, someone can potentially avoid any possibility of a spell being stealthed by casting Alarm, specifying the auditory option, then casting their actual spell with the trigger of "when the Alarm bell rings".

[TheFinish]

hyphz wrote:

The trick is that Sneak is usually used for movement, but the text on spells doesn't say the trigger has to relate to movement. It just says that a Sneak check fools an Auditory sensor, which isn't how the move works at any other time.

Also, is there any answer on Alarm? It seems a bit problematic otherwise, because although Alarm might not be that dangerous, someone can potentially avoid any possibility of a spell being stealthed by casting Alarm, specifying the auditory option, then casting their actual spell with the trigger of "when the Alarm bell rings".

Alarm itself specifies how it works regarding sneaking past it:

"A creature aware of the alarm must succeed at a Stealth check against the spell's DC or trigger the spell when moving into the area."

Of course to be aware of the Alarm you need to detect magic somehow, but once you know it's there sneaking in is perfectly doable.