Can a Stealth check ever be made passively?

Question

The PHB, at p. 175, presents passive skill checks as a means to represent two different kinds of in-game scenarios:

Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster....

(Emphasis mine.) Notably, the entire section on passive checks is general and agnostic as to any particular skill. It does not say these skills can be used passively, but not those. The implication, it would seem, is that any skill can potentially be used passively in the right circumstance.

For the detection-type skills -- Perception, Insight, and Investigation -- passive checks are so common and well-documented that I don't feel a need to cite sources for support. Other skills don't lend themselves as readily to passive checks, but it's at least conceivable to use them that way. For example, one could imagine using Passive Medicine to represent a character in a field hospital repeatedly diagnosing and treating injuries among troops at war, or using Passive History to represent a character's spontaneous recall of a particular fact without the player first asking "Does my character know any relevant history here?"

Is there any use-case for Passive Stealth? Or do the rules on hiding and detection (see PHB p. 177) essentially require that all Stealth checks be active?

Answer 1

It's possible, but some important differences between Stealth and Perception make it questionable

The rules on passive checks give us some guidance here. As you mentioned (bold added):

Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster

Although this isn't necessarily an exhaustive list of when Passive Perception would be used, it's the best guidance we have. So let's go through it point by point.

Average Implies Many Tries: What About Failures?

The checks that explicitly have passive versions (Perception, Investigation) are ones which you are essentially taking myriad times every second. You are always noticing hundreds if not thousands of things, most of which your mind edits out. And you are always thinking, even if you try not to. In this sense, they are similar to stealth, since stealth is more of an ongoing process than a single moment's effort.

However, where Perception and Investigation differ from Stealth is that many of these myriad checks can fail without causing the overall effort to fail, as long as some of the checks succeed. If you are walking towards an ambush, and for two seconds don't notice it, you've still "succeeded" on perceiving it if you then notice the ambush on second number 3 (and can react to it before the trap is sprung). However, if you stealthily creep forward for two seconds, and knock over a shelf of fine china in second 3, then stealthily creep forward on second #4, I think it's safe to say that your subsequent stealth won't make the effort a "success."

To summarize, when a passive check is used to represent an average result, it should be done when a failure on the check would not make a subsequent effort harder. If you fail to pick a lock, you may break or twist its mechanism. If you fail to convince someone of something, they may get tired of your attempts to sway them. But if you fail to see something, that doesn't make it less visible later. And if you fail to be silent, you can't make someone un-hear you.

What about a hidden observer?

The second point is a more viable one. A passive check could be used when a DM does not want to reveal to players that there is something happening which could succeed or fail. It's totally valid to suggest that there are times when a character might be observed secretly, and the DM doesn't want to let them know. Perhaps a seemingly inert gargoyle above is really a careful sentry, or an invisible guard is on watch. For whatever reason, it's quite possible that someone could be listening or looking for a character without them knowing.

But most of the time that a character is being stealthy, they only think they might be observed. If you only attempted to be stealthy once you'd actually seen a guard, then the guard would usually have seen or heard you already as well. Rather, most times that people attempt to be stealthy, they know that there might be an enemy ahead, and respond accordingly.

So although a DM certainly has the prerogative to assign a "passive stealth" to a character (so they can hide the fact that an observer is in the area), they risk blurring the line between situations that merit a passive check and ones that do not. And in doing so, they risk setting a "floor" to the standard stealth check, by basically allowing a passive check most times an active one would also be valid. We'll go into this in our next section.

How stealthy must you be to be stealthy by default?

Running with the "unseen observer" angle for a moment, let's assume that a character (who for the sake of simplicity, we'll assume is a Rogue) is not in a situation where they think they might be observed: not in a dim dungeon or mysterious cave, but rather walking down the street of a familiar village, or climbing the stairs of their own home. In these situations, a Rogue would be unlikely to be making active stealth checks. But a passive check could be useful to a DM, to hide the lurking menace and maintain the surprise.

Now, this argument assumes that a stealthy character is stealthy by default, which is not that much of a stretch. After all, it's easy to picture how a trained Rogue might be light on their feet during everyday activities: making only a muffled footsteps as they traversed their own home, or seeming to appear suddenly to a group of friends. These activities might be second nature to a Rogue, the same way that a brawny Fighter might always lift heavy loads with athleticism and grace, even if they weren't trying to show off.

However, it's worth asking exactly how trained or experienced a Rogue needs be to attain this particular level of mastery: where even without trying, they are notably competent at their common skills. And there is an in-game answer to this question: 11th level.

Reliable Talent

By 11th level, you have refined your chosen skills until they approach perfection. Whenever you make an ability check that lets you add your proficiency bonus, you can treat a d20 roll of 9 or lower as a 10.

An 11th level Rogue gets this powerful advantage. To assign a Passive Stealth result before 11th level, then, might be over-valuing the skill level of the character. At the very least, it would be stepping on the toes of an 11th level ability, many of which provide class-defining advantages (especially since there's no way that one character can have 11+ levels in more than one class). As such, giving someone an ability that is similar to an 11th level class ability (which they have not earned) is something I'd highly advise against, without serious thought.

You might be missing out

If you are the DM of a game, and you think that a passive check is warranted, then you are correct: it is the DM's prerogative to call for checks, active or passive, at times they deem appropriate.

But it's worth asking yourself what the passive stealth check is for. If it's for determining the average result of many stealth checks, then consider that those "many" checks may have some failures in them. And if it's for hiding the need for a stealth check from players, keep in mind that stealth, by its nature, is usually done when its need is uncertain.

And perhaps just as importantly, ask yourself what you gain and lose by a passive stealth check. Consider that a "passive perception" check will prevent the players from feeling like they are missing out: after all, if you call for a perception check, and then declare they see nothing, a player will likely feel cheated (perhaps there is something here, but I'll never know). But if a player is asked to make a stealth check, and then told nothing happens, how are they likely to feel? I suspect that the check will either add to a feeling of competency (if the player believes they succeeded) or a feeling of suspense (if they believe they failed). Either of those feelings is a valuable addition to many games: so ask yourself if it's worth losing out on them before you decide on a passive check.

Answer 2

The problem is, there are two uses of the word "passive" and the rules don't do a good job distinguishing them.

You need to ask - is the character actively doing something or is the player actively doing something?

Character Activity

Conan tries to lift the gate. Bêlit tries to intimidate the guard. Akiro tries to calm the panicked horses. These are all active uses of skills.

Akiro reads some runes. Does he know what they mean? Bêlit spots a particular pirate galley. Does she know who the captain is? Conan walks towards a pit trap. Does he notice it before he falls in? These are all passive uses of skills.

Generally, only "knowledge" and "observation" skills can be used passively. Things like athletics, intimidation, and animal handling require the character to actually be doing something. I'd argue that stealth is the same.

Player Activity

Conan's player, Robert, needs to determine if Conan spotted the pit trap. He picks up a d20 and rolls a Wisdom\Perception check. That's an active skill check.

Robert's DM, Lin, wants to maintain some tension at the table by not asking Robert to make the roll, so he compares the pit trap's difficulty to Conan's passive Perception score.

Alternatively, Lin needs Robert to make a perception roll for a large number of traps. Rather than make Robert roll multiple times, he compares the various difficulties to Conan's passive score.

Combining them

It won't cause any issues combining these as long as you are clear about which "passive" you are using.

Answer 3

All skills can be used passively

In theory anyway.

An example of a use for passive Stealth is in long distance travel - what we have here is "a task done repeatedly". When the party sets out on a two week overland journey its perfectly reasonable to use their passive Stealth. And also use the passive perception of the creatures that are looking for them - and vice-versa. It saves a lot of needless dice rolling.

Note that this is a Group Check and "If at least half the group succeeds, the whole group succeeds. Otherwise, the group fails." What this means in practice is you use the passive score of the character in the middle (if there are an odd number) or the one at the bottom of the top half (if there an even number).

Answer 4

Kind of.

As you say, the rules don't specifically exclude the possibility. Its just doesn't make quite as much sense.

You are always aware of your environment to some extent - you don't really have to make an effort to see what's around you for example - so by its very nature "seeing" has a passive component. Although you can make an effort to take more notice of what's going on if you want to.

Hence a skill check can be passive if what the character is doing is, itself, passive.

Moving stealthily, though... this is not, by its nature, a passive action as a character naturally would move... normally. So it makes less sense.

However:

Having said that all that, if a character states that they are always moving stealthily unless otherwise noted then there is no reason why a DM couldn't just use their passive stealth check as a guide to what other creatures in the area notice them. This would remove the need for the DM to keep asking the character to make stealth checks so does provide a benefit.

(Note that there do not appear to be any rules stating that a character moving stealthily moves more slowly in a tactical environment, though it would be reasonable to assume that a character being stealthy would be moving more carefully and therefore slower. This would be a DM decision; it probably wouldn't have much game effect beyond atmosphere.)

Answer 5

Personally, I've entertained the idea of checking passive stealth when I need to determine if one character hears the other, even if he is not hiding.

Imagine a party rummaging through a room. Behind the closed door is another room, where a princess sits, having not gone to a ball, due to upset tummy. Party didn't realize this and is not actively hiding, just walking around. They don't make any particular noise either, just walking from wall to wall, looking at papers or something.

Does the princess hear them (and call the servants with a bell, or just look out the door to see what's that all about)? If they're a party of monks-rogues, I'd say they naturally walk silently, without trying much, and can stay unnoticed. However, if there's a warrior in heavy armor, he clanks quite loudly as he goes, and will probably be heard.

Answer 6

Yes.

I use that to figure out the level of perception needed to notice ambush.

Last time I used it was to see if players detected giant spiders waiting in their web (10 + 7 stealth bonus= 17 perception check/or 17 passive perception to notice).

I personally would not use passive stealth if the creature is moving, only while staying still and also give this option to my players. You have to decide this before you roll stealth of course. If a creature moves stealthily I make them roll stealth.

Answer 7

It's balanced as a GM ability, and they may well do it, but not as a player ability for stealth.

A GM might decide that the goblins have a proficiency of 3, and a dex bonus of 2, so that the DC for detecting an ambush will be about 15. This is an easy method of book keeping, and they have discretion to make passive checks.

As a PC check, it's fairly potent.

Rogue can do a version. Rogue has a talent that gives them a similar auto 10 at level 11.

Reliable Talent By 11th level, you have refined your chosen Skills until they approach perfection. Whenever you make an ability check that lets you add your proficiency bonus, you can treat a d20 roll of 9 or lower as a 10.

So, any stealth check they make will reliably be over 10, and so auto succeed against many challenges. You don't even need to roll, often.

Since rogues tend to have a high proficiency bonus and stat modifier for stealth, passive stealth would remove most of the risk of stealth. That's why it's a level 11 ability. Giving that to players at level 1 would be a fairly large boost in power, and substantially weaken the Rogue's comparative power.

Answer 8

If a tree falls in the woods, did it pass the stealth check?

Passive checks are just that, passive. No extra effort is given/taken for it to occur. It's just the character being the character. Either not trying, or doing something by rote.

Also, realize that "stealth check" is a misnomer. It's really a "stealth challenge".

You can have advantage and roll two natural 20's with a +10 proficiency bonus, but it doesn't really matter until someone is looking for you. You're stealth roll is challenged by the seekers perception. Per the PHB:

When you try to hide, make a Dexterity (Stealth) check. Until you are discovered or you stop hiding, that check's total is contested by the Wisdom (Perception) check of any creature that actively searches for signs of your presence.

Note the emphasis...

Let's look at the two situations of being passive: Not trying, or doing something repeatedly.

If you are not actively trying to be stealthy that means you're not taking any precautions to stay that way; not being quiet, no tippie-toes, not holding breath, not holding equipment to keep it from rattling/clanging/scraping, etc. And per the description of Hiding, you need to try.

You should to be actively looking for a place to best hide; shadows, behind boxes, under the wizard's robes, etc. You also need to be aware of your own body. Otherwise you are like a 3-year-old playing hide-n-seek; stick your head in the closet but leave your butt hanging out.

For "a task done repeatedly"; what action do you envision is being stealthy repeatedly?

If you're standing still, then it's one roll, and you're actively trying to be in the best hiding spot available. If you're on the move, then you are actively looking for a new spot each time you move.

Answer 9

I use Stealth and all skills Passively and also “actively” as in making a roll.

I think Stealth is a great example of why. It sets a base level of “stealth” when you aren’t giving it any extra effort. That is, I think some people are naturally more “stealthy” than others. But rather than thinking of just people, I’ll ask this:

Do you think a deer moving through the woods is naturally more stealthy than most humans?

I do. Even when they aren’t “trying” to be stealthy, they are very quiet. That to me is Passive Stealth.

Another example - the party of PCs is walking down a dungeon passage. Around the corner a party of orcs is doing the same. Do either of the parties notice the other one?

With Passive Stealth and Perception (or Investigation - I use either), it’s easy to know. What’s the worst modified Passive Stealth score of the group?

I will also point out that Passive Perception doesn’t precisely fit either of those two categories. It could be “the average of many tries” but that wouldn’t apply to a momentary thing that happens once (stepping on a twig for example). Likewise, the DM may not inherently be trying to hide success/failure, and they could also hide success/failure by rolling behind the screen.

In other words, do you read those to examples as “exclusive” and no other uses are appropriate, or “inclusive” where they are two examples, but not the only ones.

Personally, I think using Passive scores as the base check for everything makes a near perfect system. But it also means you’ll need to modify Reliable Talent.