Using the Rules Better: A Return to Passive Stealth
It’s been a while since thinking about the possibility of Passive Stealth prompted me to consider the overall topic of contested checks in 5E, and to decide that they aren’t a terribly good mechanic. You can always go back and read the previous article about contested checks, but suffice it to say here that I think it makes much better sense from a design perspective to get rid of contested checks in favor of having a d20 roll for one side of the contest and a DC to roll against for the other. Unfortunately, despite the various benefits of using that design instead of contested checks, I didn’t get much closer to solving the problem with stealthy movement. Sure, getting rid of contested checks meant that we wouldn’t be using them to determine the success of moving stealthily, but that didn’t seem to address the overall problems that crop up when the party wants to sneak around. Well, after some consideration, I think I have a solution for you… even if it isn’t based much on the contested checks fix.
Stealth Without Contested Checks
If we just implement the contested checks fix, the stealth issue resolves itself as a Dexterity(Stealth) check rolled by whomever is doing the sneaking, against the Passive Perception (as with a DC) of whomever is supposed to not notice. That’s much better than the contested check mechanic, but it still isn’t a very good solution, because groups sneaking around is still almost impossible.
Let’s assume that we have a standard party of four characters, and let’s further assume that none of them have Stealth proficiency, and also that they all have decent Dexterity. Each of them will be adding +2 to their d20 rolls to move stealthily.
The party will be sneaking by a single guard, so in accordance with the contested checks fix, we will choose a DC to use instead of rolling a contested check between the guard’s Perception and the party members’ Stealth. We’ll make this guard a fairly lousy specimen, and set the DC for sneaking by him at 10. Probably this would be higher, as most NPC’s and monsters tend to have at least some bonus to Wisdom, and a guard might even have proficiency in Perception, but we’ll stick with the unobservant guard because I have a point to make.
So, if the DC to sneak by the guard is 10, and the PC’s each get to add a +2 to their checks to sneak by, that means that each of the PC’s will need to roll an 8 or better (I resolve ties in the favor of the players) to sneak by the guard. For the entire party to sneak by, all four of them will have to roll an 8 or better; if one of them fails, then at that character will at least be noticed and the overall goal of the party sneaking by will also fail.
How likely is this to work, then? There’s a 35% chance that any of the individual characters will mess up badly enough to be noticed, but when we consider that we need none of them to mess up, the odds swing significantly against an overall success for the party. Just for starters, the chance that the first party member will screw up the attempt is 35%, but even if he makes it then the chance that the second party member will be the one to screw it up for everyone is 22%. The chance of the third member being the one to screw it up is about 14%, and the chance of the fourth member being the screw-up is 9%.
Remember, though, that the chances of each successive member being the one to mess it up for everyone are getting less because it’s increasingly likely that an earlier member will be the one to mess it up. We have to add up all of the results, so the chance that at least one of the party members will ruin the sneaking attempt is about 80%. And that’s for sneaking by a single guard who isn’t the most observant individual to begin with. If we had multiple guards, or guards who were actually chosen because they were alert fellows with keen senses, it just gets worse. Even if we just had two rather unobservant guards, and had to roll checks to sneak by each of them, the odds of the whole party successfully sneaking by both of them drops to right around 4%.
So, that whole idea of fixing contested checks in order to fix stealth… doesn’t help here. Don’t get me wrong, it works great in a lot of other situations, and it’s still (almost) always better than using contested checks. The stealth problem inspired that hack, but unfortunately the hack doesn’t actually help with the issue it was originally developed to solve.
Oh well, then. We’ll just have to try something else.
Back to the Basics: Action Adjudication
The first step towards fixing this problem with stealthy movement is to go back to our first principles of action adjudication: we need to consider whether the attempt to sneak can succeed, and we need to consider whether the attempt can fail. If an attempt to sneak either can’t succeed or can’t fail, we have no business rolling dice in the first place, so let’s think a bit about what situations impose immediate success or immediate failure for characters trying to move stealthily.
Bear in mind that the emphasis in this article is going to fall heavily on sight as the sense that determines success or failure, because in most cases it will be. Hearing comes in second, so please remember that when I’m talking about characters being seen that characters making a lot of noise will be heard as well. I doubt that any enemies will be smelling out characters trying to move stealthily, or somehow tasting them as they try to sneak by. But remember to consider noise, even if I don’t place a lot of deliberate emphasis on it.
Sneaking That Can’t Fail
We’ll get this one out of the way first, because it has less potential for complexity than the other side of the coin. When do we know that an attempt to sneak can’t fail?
Something that we know about any sneaking situation is that there has to be someone to sneak past. Yes, it might very well be that the player thinks there’s someone to sneak past when in fact there isn’t, but it’s not possible for a character to sneak badly and be noticed when there’s nobody there. Why am I even bringing this up? The DM might have cause to pretend that there are observers, if the characters would have reason to doubt whether there were any. Just because the PC’s can’t see an observer doesn’t mean there isn’t one there, and just because there isn’t one there doesn’t mean they have to have certain knowledge of that fact.
It might also be that there are possible observers, but for some reason they are incapable of observing. Enemies without darkvision or a light source can’t see in the dark. Enemies with abilities like echolocation or tremorsense can be baffled if there’s an excess of noise or vibration, or even no noise (silence spells) or no vibration (flying or levitating characters). In those cases, we need to consider the possibility that the attempt to sneak can’t fail, and that dice are not needed.
Even without having to deal with special modes of perception like darkvision and tremorsense, there are plenty of mundane reasons why observers might not be able to observe as the party sneaks by. Maybe the party is sneaking through a room full of sleeping enemies. Maybe there’s thick smoke or fog, or lots of noise from weather or machinery. There will still be a danger of being caught in some of these situations (sleeping people can be woken by clumsy noise), and we will deal with that later, but situations certainly exist where nobody will be able to notice the party moving past. If they’re moving through a white-out blizzard with howling winds by feeling their way along a guide rope, we don’t need dice to know that they won’t be noticed.
Sneaking That Can’t Succeed
This part is not difficult to conceptualize. Unless you’re under an invisibility effect, if someone is looking directly at you, they are going to see you. You can’t sneak by a guard, sentry, or other onlooker if they are looking right at you. So, if there’s someone watching a hallway, or a door, or a gate, nobody can sneak through it. Dice do not need to be rolled to know that if you step into someone’s field of view, under normal circumstances, they are going to see you.
Not Normal Circumstances
The issues of “lightly obscured” and “heavily obscured” come up here, and even though they are awkward concepts, I’m going to get into them because they’re in the 5E rules and should probably not be thrown out without at least some discussion. The problem with lightly and heavily obscured areas is that they are not really quantifiable; the PHB gives a general idea of what areas count as lightly or heavily obscured, but aside from some mechanics involving disadvantage on perception checks and on when it’s possible to hide (another problem of its own, which we will address later), obscured areas don’t do much.
So, we’ll redefine them, and because they have to do with visibility, we’ll base the definition on how well you can see in obscured areas, and we’ll keep it simple. Heavily obscured areas can’t be seen in at all: if an area is heavily obscured because of darkness, then a light source fixes the issue, but areas that are heavily obscured because of smoke or fog remain heavily obscured even with light. That goes for magical darkness as well, which has its own definitions that mostly don’t need to be tinkered with.
Lightly obscured areas are more along the lines of dim or misty, so in order to define them in terms of what you can see, we’ll say that you can only see things in lightly obscured areas when you know what to look for and where to look. If you’re watching a door in a lightly obscured area, and someone opens it, you’ll notice. If you see someone move out of an non-obscured area and into a lightly obscured area, you’ll still be able to keep track of them, but you’ll probably lose them if they move while you’re looking away. Also, there are some mechanics involving hiding in lightly obscured areas, but we’ll get back to those when it’s time to discuss hiding in general.
Doors Opening, Doors Closing
Doors are a problem for characters who want to sneak around, because sneaking through a door is always difficult to manage. There are ways to deal with them, just like any other obstacle, but a closed door creates serious complications for characters moving stealthily.
The main problem with doors is that you can’t really open or close them without someone noticing. Obviously if someone is looking directly at the door, like a lookout, or if someone is standing right next to the door, like a guard, then that door can’t be opened without alerting someone, and any attempt to sneak by will fail, no dice needed. Even if they aren’t specifically looking at the door, people in a room will probably notice it opening, and then someone coming in through it, unless either they’re very distracted or some special measures are taken.
Level of distraction is best left to DM discretion, and I’m not going to try to set out mechanics for deciding what might be going on in a room that would prevent those inside from noticing a door opening and someone coming through it. “Special measures” can cover a few different things, but the most common examples are coming through the door using magic or the like (a character seeping into the room under a gaseous form spell would likely go unnoticed), or taking some precautions to prevent noise (like carefully oiling the hinges and other hardware, or casting a silence spell around the door area). Bear in mind, though, that none of this will help if someone is actively watching the door. Distractions, spells, and oiled hinges only matter if there are people in the room, but they’re paying attention to other things.
Remember, though, when we’re talking about doors, that we mostly aren’t rolling any dice to deal with them: they’re just reasons why dice aren’t needed. There might be cause for a Sleight of Hand check to be rolled in order to very carefully open a door that’s been doctored up to open without creaking hardware, but for the most part doors are just a reason for stealthy movement to not be able to succeed. That’s rather unfortunate, but it can’t really be avoided. Doors are a problem, and they are a common problem, and there are not a lot of effective solutions for that problem. Well, we never said it had to be easy.
Hide and Sneak
There’s a prerequisite for sneaking that we’re going to need to cover before we can get into the kind of sneaking that can succeed or fail: you can’t start sneaking if someone can see you. And that brings us to hiding, and to the idea of being hidden.
Being hidden is another one of those things that doesn’t require rolling dice. You can be essentially hidden because you’re in a heavily obscured area and nobody can see anything, you included. You can be hidden because you’re in a lightly obscured area, and nobody is directly looking at you, and you’re standing still and not drawing attention to yourself. You can be hidden because there’s something blocking the line of sight between you and whomever you’re hiding from. When it comes right down to it, being under the effect of invisibility or greater invisibility more or less makes you hidden.
And, of course, the way you get hidden is to take some action to hide, and this is also something we don’t need dice for. The basic notion is that before you take the action, you can be seen, and after you take the action, you can’t be seen and nobody can figure out just where you are. If there’s a single box in the room, and you dive behind it, then even though you can’t be seen everyone knows where you are. That’s not hiding, that’s taking cover. However, if you’re in a warehouse full of boxes, and you dive behind one of them, then you’re hidden, because you could have moved behind any of the other boxes, making your actual location unknown.
There are skills, racial and class abilities, and all kinds of other mechanics in the 5E rules that have to do with hiding and the special circumstances under which various characters can pull it off when normally it wouldn’t work. For the purposes of this article, all of those mechanics still work; there’s no reason they shouldn’t. Just be aware that being able to hide successfully under unusual circumstances doesn’t automatically provide the ability to sneak around once you’re hidden. It’s also at the DM’s discretion as to whether you can quickly hide again and continue to be undetected if you give your position away while sneaking.
Sneaking With Risk Involved
Once we get beyond sneaking that can’t fail and sneaking that can’t succeed, we come to the place where things get interesting. Fortunately, most kinds of sneaking do fall under the can’t-fail or can’t-succeed categories. For the rest, I’m going to propose a really simple mechanic to decide whether characters can move stealthily: if you haven’t been noticed, you can move without being noticed until you draw attention to yourself. This will take some unpacking, but it’s deliberately intuitive so that the DM doesn’t have to spend a lot of time figuring out mechanics. We’ll go through one item at a time.
Not Being Noticed
First, if you’re successfully hiding, then you count as not being noticed. There are ways of not being noticed other than hiding, but hiding always counts as not being noticed.
Second, if somebody is not looking at you currently and hasn’t looked at you previously, you count as not being noticed by that person. This works collectively as well, so you might count as not being noticed by a whole group of people… but if just one of those people looks at you, now you’ve been noticed.
Third, if there’s nobody around except you, and possibly your allies, you count as not being noticed. This should go without saying, and it’s also just a special case of the previous point, but we’ll put it out there explicitly for the sake of clarity; all this really means is that if you start your stealthy movement in an empty room, you don’t have to take any special measures to hide before you can start sneaking into the next room.
Drawing Attention to Yourself
There are two basic ways in which a character can draw attention to herself. There’s a way in which it can be done without needing to roll dice, and a way that does require rolling of dice.
Attention Without Dice
Simply put, if you’re trying to sneak and you take an action that would place you under any of the circumstances given in the section above about “sneaking that can’t succeed”, then you have drawn attention to yourself. Move into someone’s field of view, open a door in a way that gets the attention of someone in the next room, leave any obscured area, or mess around with something in a lightly obscured area that’s being actively watched, and you will be noticed. No dice need to be rolled for these, just based on the principles of action adjudication. If it can’t be done, don’t roll dice about it.
Attention With Dice
This is probably the section that everyone has been waiting for, but I think it’s probably the least important part of this article. That doesn’t mean it’s going to be short to discuss or easy to design, but hopefully it’s the part of the design that needs to be used the least. We’ve covered almost all of the ins and outs of hiding and sneaking without needing dice at all, and I count that as a win… the whole point of this article was to come up with something that I started out calling “passive stealth”, meaning the ability for characters to move stealthily to a certain degree without requiring dice to be rolled, much like passive perception allows characters to notice things to a certain degree without requiring dice to be rolled. And now we have a way for characters to move quietly and evade notice to a certain degree without requiring dice to be rolled. Well, mostly without requiring dice to be rolled.
Of course, eventually the dice get involved. The time we’re going to need dice when dealing with stealth is to decide when unfortunate things happen that cause characters who are sneaking to accidentally draw attention to themselves. Because I like to stick with designs that work, and because the d20 System is easily understood and frequently used in D&D, we’ll handle attention-getting mishaps using a normal d20 roll, with some modifiers, that will be compared to a DC. Just like we do all the time in this game, and have been doing for years.
The initial inclination here is to choose a DC that reflects how difficult it is to sneak past a particular opponent or group of opponents, with a higher DC for enemies with higher perception, and an adjustment for more enemies to account for more sets of eyes and ears, or something along those lines. That’s not how we’re going to do it, though, because this DC isn’t about how hard it is to succeed in sneaking past specific enemies. This DC is about how easy it is to fail in sneaking in general.
What it comes down to is this: if we’re following the model I’ve set out where sneaking works until someone notices you, then the DC needs to be based on avoiding accidentally drawing attention to yourself. For most characters, most of the time, that shouldn’t be too hard to do: just avoid stepping on branches or knocking over furniture, and people who haven’t noticed you will probably keep on doing what they were already doing, and your movement will continue to go unnoticed.
So this DC is going to be low. Really low. So low, in fact, that it will seem almost laughable. So low that we’re even going to have some problems deciding how low to set it, because the normal probabilities are awkward when the numbers get small, and especially when we start talking in terms of “not failing” instead of “succeeding”, which in D&D mechanics aren’t quite the same thing. We’re going to have to be very careful with setting the DC and determining what modifiers should be added. There are some side considerations as well, mostly dealing with house rules concerning d20 throws and how to resolve ties.
It will matter if your house rules say that a natural 1 is an automatic failure, outside of attack rolls. Yes, the rules-as-written don’t say anything about natural 1’s and natural 20’s being special unless it’s an attack roll, but a lot of tables don’t do it that way. Maybe they like the feeling that comes from the ever-present possibility of crushing failure or amazing success through sheer luck. Maybe they didn’t read the rules carefully and they think that the automatic success and failure d20-roll mechanic is intended to be universal rather than just for attacks.
The difference here will mostly come down to whether you think it’s a good thing for even the most stealthy character to constantly have a 5% chance of a stealth-ending mishap. This could go either way, and it’s really a matter of preference: some people like the confidence of a sure thing, and would prefer characters with sufficiently high modifiers to have guaranteed success, while other people like the excitement that comes from knowing that anyone can fail if their luck runs out. It’s your choice, and it doesn’t make much of a difference to the design here, as long as it’s clear how it applies.
You’re also going to have to decide clearly up front whether a check has to exceed the DC for success, or whether a tie between the check and the DC is sufficient. With low DC’s, this can be a much more pronounced difference than with the normal-range DC’s that apply to most checks, and it’ll be a little more clear later on just how much difference it makes between success on a tie and failure on a tie.
Stealth Checks for a Low DC
Now, when I’m talking about choosing a low DC, bear in mind that I’m talking about a DC of around 5. Maybe a little more, maybe a little less, but we’ll use 5 as a starting point. The main problem with a DC that low is that we will have difficulty keeping the check relevant. With a really low DC, many characters will be adding bonuses from stat modifiers and proficiency that will result in their passing the check every single time. If you go with natural 1 as an automatic failure, then you won’t get 100% success as an outcome, but you can absolutely get 95% success as an outcome if the modifiers get you above the DC, even if you roll a 2 on your d20 check. If a natural 1 doesn’t mean anything special, then 100% success for characters with high enough modifiers is possible, and with a really low DC, “high enough modifiers” don’t need to be very high.
Considering the low DC, there needs to be a change made in order to avoid the problem with automatic success on Stealth checks. According to the PHB, the check required is expressed as Dexterity(Stealth), which is your DEX modifier plus your proficiency bonus as applicable. When we change up the modifiers to work with the low DC, the main difference is that the Dexterity modifier will not be added to the roll. We aren’t doing Dexterity(Stealth) as set out by the PHB. We’re doing something more like Nothing(Stealth). If a character has Stealth proficiency, then they can add their proficiency bonus to their d20 roll, but nobody gets to add their Dexterity.
I’ll give you two reasons to leave DEX out of the calculation: a mechanics reason, and a common-sense game-world reason to back it up. The mechanics reason is that if we allow everyone to add their DEX, then we have to set the DC high enough to not make the check an automatic pass for high-DEX characters (meaning those with at least a +3 modifier, which isn’t exceptionally high), but not so high that low-DEX characters don’t get reasonable odds of success. This is complicated by the fact that DEX is one of those stats that characters either have a lot of, or else not much at all. You don’t find a lot of middle-of-the-road DEX stats out there. You also don’t find a lot of characters with Stealth proficiency who don’t have high DEX, and that messes up the numbers even more. If we’re going to choose a DC that provides reasonable risk of a stealth-ending mishap across the board, DEX needs to be out of the situation entirely.
As promised, we can explain this in terms that make sense from an in-game perspective. When this check is being rolled, it’s to avoid a mishap that would draw attention to the character. Characters who have Stealth proficiency will have been trained to move quietly, notice subtle hazards like gravel to grate and small puddles to splash, and otherwise do a better job avoiding noisy accidents when creeping along. That’s why we add the proficiency bonus for characters who have the Stealth proficiency. However, the Dexterity issue is more one of diminishing returns. You don’t have to be a champion acrobat to avoid tripping over larger objects or even your own feet, and in fact there’s probably not much difference between champion acrobats and everyone else as far as the usual stumble-and-fall accidents go. Mostly they don’t happen, and when they do, they really are accidents and tend to be unavoidable as many accidents are. Maybe the high-DEX characters would avoid damage from tripping and falling using some graceful ballet moves, but we aren’t worried about damage. We’re worried about drawing attention, and good enough is good enough, and great isn’t necessarily that much better.
That having been said, if there’s a character with a negative DEX modifier, that modifier has to be subtracted from the Stealth check, because being a klutz does in fact make you more likely to stumble and get noticed while sneaking along. So, if DEX is your dump stat, being sneaky is going to be difficult. If your DEX is better than average, even a lot better, it’s not going to make much difference when you just have to avoid tripping over your own feet.
Passing Without a Trace
This whole system of passive stealth throws a massive kink into the mechanics of the pass without trace spell. Or else pass without trace throws a massive kink into passive stealth.
The upshot of the spell is that the caster and all of her companions get a massive +10 to their Dexterity(Stealth) checks for an hour. This has always been a problem, but it’s especially a problem since we’ve done away with Dexterity(Stealth) checks. I’ll propose two ways to fix this spell: a general fix that makes the whole situation less ridiculous, and a specific fix that makes it not break the passive stealth system.
In general, I recommend that DM’s limit the effectiveness of pass without trace based upon the environment where it is used. Inside buildings, on city streets, or in other non-natural and constructed areas, the spell only works to prevent the affected creatures from leaving any signs which could be used to track them. In closed natural environments, like stone caves or dirt tunnels, the spell works more or less as described, but it doesn’t work nearly as well as it does in open natural environments, like forests and grasslands. The point is that the spell’s ability to shield the caster’s allies from detection is dependent on there actually being places to hide in the environment, and that a natural environment is needed for a ranger-and-druid spell to work effectively.
The whole spell description about “a veil of shadows and silence [that] radiates from you” is suspiciously like an invisibility spell, and adding +10 to any check is pretty much a guaranteed pass. And yet pass without trace is only a second-level spell. Never mind how this veil of shadows moving around would look… not suspicious at all, I’m sure.
As far as the passive stealth system works, the best way to handle castings of pass without trace is to grant proficiency in Stealth in closed natural environments, and double proficiency in Stealth in open natural environments. In non-natural or constructed environments, the spell has no effect whatsoever on the operation of passive stealth. Problem solved.
Choosing the Magic Number
So, when we choose that DC, the numbers that make a difference are the proficiency bonus by level and the average rolls from a d20 with no modifiers. Characters with proficiency will be adding their proficiency, and all of the other characters will be adding nothing. Using my own house rules regarding automatic failures and how to handle ties, I’ll go through this assuming that a natural 1 always means a failed check, and that ties are resolved in the favor of the players.
The fact of the matter is that no matter where we set the DC, characters with proficiency are going to reach a level where they’ll have that 95% success rate every time. It’s just a matter of at what level, and fortunately we can predict that because the proficiency bonus increases regularly for all characters: starting at +2, it increases to +3 at fifth level, to +4 at ninth level, to +5 at thirteenth level, and finally to +6 at seventeenth level.
That means that a DC of 5 is an automatic success for fifth-level characters, ninth-level characters always succeed at DC 6, thirteenth-level characters always succeed at DC 7, and so on. At least using my house rules; you can figure your own out easily enough by subtracting the lowest possible successful roll (either a 1 or a 2) from the total number needed to either tie or beat the DC, and comparing the result to the proficiency bonus chart.
The fact of the matter is that we need to deliberately not worry about automatic success happening for proficient characters at levels that seem too early. It’s going to happen eventually, after all. Also, because the entire party is probably not going to have Stealth proficiency, the overall liability concerning sneaking around as a group settles on the non-proficient characters. Letting the stealthy characters scout around by themselves with reasonable confidence is no harm, especially if you play natural 1’s as automatic failures. Finally, remember that this whole dice-rolling part is going to be the most seldom used and overall least important part of the whole passive stealth system.
All of that being said, let’s figure out the best DC. We’ll start with a party of four characters, none of whom have stealth proficiency, and then adjust the numbers to include some party members who are proficient, because most parties will have at least one member proficient in Stealth. If our hypothetical parties can come out of this with a good chance of sneaking through an area without drawing anyone’s notice, we’ll have done what we needed to do.
For a DC of 5 (and remembering that I’m resolving any ties in the players’ favor), an individual character without proficiency has an 80% chance of evading notice, and a party of four such characters has about a 41% chance of all making it through without drawing anyone’s attention. If you give one of the characters a +2 proficiency bonus, which is the lowest possible proficiency bonus, then that character has a 90% chance of evading notice, and the entire party has a 46% chance of all making it through. And, if you increase that proficiency bonus to +3, the party has a 49% chance of overall success.
In case you were wondering, changing the house rules so that a natural 1 is not an automatic failure doesn’t make any overall difference until you raise the proficiency bonus for the one character to +4, at which point the party has a 51% chance for success.
Now, when we set the DC to 5, we have to accept that a fifth-level character will have odds of success that are as good as they’re ever going to get; that character can only fail the check on a d20 roll of natural 1, because even a roll of 2 with a +3 proficiency bonus will meet DC 5. If we either eliminate natural 1 as an automatic failure, or else require the players to exceed the DC, the point of guaranteed results doesn’t happen until ninth level. If we do both of those things, we put it off until thirteenth level, where even the lowest d20 roll combined with a +5 proficiency will exceed DC 5, making that a true 100% chance of success.
And the Winner Is…
If, like me, you like natural 1’s to fail automatically, and players have to meet the DC but not exceed it, I recommend DC 5. That 40% base chance of party success isn’t great, but it’s a lot better than the 20% chance that we looked at when the party was trying to sneak by a single underqualified guard. Personally, I’m inclined to stick with DC 5 even if I’m a little underwhelmed by that 40%, because dropping the DC to 4 would mean that even a first-level character with stealth proficiency would already have reached that superlative can’t-get-better-odds-than-this point, and the overall success for the party without any proficiency would only rise to 52% in exchange, or to 58% with a single proficient character in the party. I’m not crazy about fifth level being the point of ultimate stealth mastery, but I definitely don’t think the numbers improve enough to justify having first level characters at the functional pinnacle of stealth.
If I cared enough about raising the level at which the odds of success with stealth max out, I would probably try a DC of 6, which would make ninth level the point at which the chances don’t get any better further along. However, that would drop the overall party odds to just 32% without proficient characters, and I’m not sure I would find it to be worth the trade-off. It might sound like a good trade to you, though, so now you have the numbers to consider.
The Final Wrap-Up
The way to get a “passive stealth” that allows individual characters or whole parties to move around quietly and cautiously, gaining the benefit of not being seen or heard until they do something to give themselves away, is primarily based on adjudicating stealthy actions according to the tried-and-true method of asking whether the stealthy movement can succeed, and whether it can fail. The fact is that most of your situations involving sneaking can be resolved this way, and that’s a good thing… because it’s simple, and because it makes sneaking around not dependent on a lot of rolling of Dexterity checks, or Stealth checks, or any other checks. After all, the point of having something as a passive ability is to eliminate the need for so many checks, so we’re meeting the conceptual requirement here.
If we really need to handle a situation where success isn’t guaranteed and failure isn’t automatic, we can roll some dice to figure out whether individuals or groups can manage to sneak by their enemies, if the conditions are right. Don’t think of this in terms of characters moving stealthily enough to defeat the observation skills of the adversaries, but in terms of characters not doing anything clumsy or stupid and giving themselves away. We set a low DC, limit the modifiers that can be added to the check, and let the characters do their best to not engage their enemies’ attention. It’s far from a sure thing, but the odds aren’t all that bad, and clever players can probably come up with ways to boost their chances with magic or guile.
The question I’m left asking myself is this: if it’s possible to have this passive stealth, and anyone can use it more or less all the time, why are we even bothering to make it a thing? There are two answers here.
The first, most important answer is that passive stealth applies to groups, but it applies to them because groups are composed of individuals, and the true value of passive stealth is so that your rangers and rogues can sneak and slither and scout around without having to roll dozens of checks, at least one of which will go poorly and leave them exposed deep within enemy territory. The chances of entire parties sneaking around are less than compelling, but that’s a reasonable outcome, because the fact is that groups do not sneak well.
If a lot of this article seems focused around parties moving stealthily as a group, that’s because groups being stealthy is more complicated than individuals being stealthy, and more complicated things take up more space for mechanics and how they work. Really, I think the greatest strength of the passive stealth system is that it allows the truly stealthy characters to have their moments of glory as scouts and thieves and assassins. My vision here is not primarily one of groups sneaking around, but instead of individual characters sneaking around with confidence and effectiveness.
The second answer as to why we’re bothering to have passive stealth when it can work all the time is that it makes sense for it to work all the time. When you’re adventuring around in dangerous places, you don’t go loudly and advertise your presence. You move quietly, you avoid making noise, you keep your voice down and your lights shaded. I suppose you might consider that moving around quietly takes more time to get places than moving normally, but I honestly don’t think that it should make much difference at all on the 5-foot or 10-foot grid scale. Also, it does nobody any harm for the party to move around cautiously, especially since the flow of the game isn’t being interrupted by constantly taking time to roll and evaluate checks. Most of what’s needed is for the DM to realize when the sneaking can’t fail, and when it has to fail, and that’s not a lot of additional plates to spin.
So, there you have it, and it works more or less as I wanted it to when the issue first came up. And, even if passive stealth doesn’t use the contested checks fix that I came up with in the first place in order to make it work, coming up with the fix for contested checks was a good thing anyway. Now, go forth and sneak… and try not to trip over your own feet.