D&D (2024) Auto-succeed/fail on ability checks

[Maxperson]

Sorry—are you accusing me of not reading the rules?

Not at all. It was just a humor post. I do humor posts a lot. If I were accusing you of that, I'd say it straight out. People who have been here longer can confirm that I'm pretty straightforward and blunt.

 

[Ibrandul]

You know 1D&D already answered this whole discussion effectively by saying don't allow checks where the DC is 30 or higher right? (Also: never ask for a roll when the DC is 5 or lower). Huge numbers of people seem to have missed that entirely. This entire discussion seems to have missed that, in fact.

I do know that. I'm describing a situation where the ability check DC is (say) 25, but the PC can't get up to a 25 result with a nat 20 + mods, because their mods are +4 or less.

I think everyone agrees that in this situation, if the DM calls for this ability check then under 2014 RAW it would fail no matter the roll, whereas under 1D&D it would succeed on a nat 20.

What some have argued is that, under 2014 RAW, such a check is prohibited in the first place: the DM must first determine whether a 20 would succeed after mods are added, and if the answer is "No," then the check must not be called for.

My position is: no, 2014 RAW say nothing to prohibit the DM from calling for an ability check that would fail on a nat 20 + mods, if the DM determines that succeeding at the proposed task is possible in general.

 

[Maxperson]

A PC wants to attempt a very hard task (DC 25). It's not impossible that someone could succeed at this task; indeed, other members of the party could succeed. But the PC doesn't have a shot at it, because their modifiers can only get them to a +2 (and no one has provided bardic inspiration, etc.)

Some have argued for the following position: according to RAW, the DM should never call for an ability check in this situation, because a nat 20 would fail. In other words: if a nat 20 would fail, the task is by definition impossible for this PC and the die must not be rolled.

Okay. Now for my actual response to this post.

I haven't seen the bolded part at all in this thread. I have seen a few people say that they will for their game make that ruling, and that IS supported by RAW. The same RAW that I use for gating rolls behind proficiency, also allows for DMs to gate rolls behind bonuses. The new rule about autosuccess on a 20 only applies if an appropriate roll is called for. If the DM is answering the two questions I posted earlier today using the criteria of bonuses and possible success via those bonuses, then it would be inappropriate to allow the PC with +2 to roll for a DC 25 check.

One implication of this position is that the new "nat 20 auto-succeeds on ability checks" playtest rule is entirely superfluous except as a pedagogical redundancy to eliminate a persistent misunderstanding, because DMs should never call for any roll that this new rule would affect in any way.

AcererakTriple6 has expressed this position very clearly multiple times. You wrote some things that made me think this was your position, too. Perhaps I misunderstood.

@AcererakTriple6 has only said that he would rule that way, not that RAW requires it and the DM should never call for such rolls. While it's not my position to gate all rolls behind bonuses like that, I'm also not going allow a roll for anything I set a DC for and a character is proficient in.

What I am probably going to do is set a number between 3 and 5(I haven't decided yet). That will be the luck factor where an auto 20 could succeed. If I choose 5 and a PC is 1-5 short of being able to make the roll with his bonuses, he will still get a roll to get lucky with a 20. If I pick 3, that PC would need to be within 3 of possibly making the target DC.

There's no way in hell a commoner or even a PC with a 0 bonus is getting a roll to make a DC 30 on a natural 20. It's not happening.

The new rule isn't superfluous, but it is subordinate to the DMG rules. It only kicks in on rolls that the DM has deemed appropriate using whatever criteria the DM has chosen.

My position is: RAW do permit ability checks to sometimes be made even when a nat 20 will fail.

Sure, but only on those rolls the DM deems appropriate.

It has nothing to do with whether DMs are also permitted to say to some players, "If I permitted your PC to make a check for this, a nat 20 would succeed; but it is impossible for X or Y reason, so I won't permit it." Clearly, they are not only allowed to do so but should do so for some X's and Y's. But there's very little guidance in the RAW on what "X or Y reason" can or should be here, and there is certainly nothing to indicate that "X or Y reason" must include "because your mods aren't good enough and a nat 20 would fail, even though the task is possible in the sense that other PCs could succeed."

There is very little guidance, and I think that's intentional. This edition was designed to be rulings over rules and the more guidance provided, the more tightly constrained DMs will feel. They leave it wide open for the DM to determine what criteria will be used to deem a roll automatically successful, automatically unsuccessful, or require a roll.

 

[Maxperson]

You know 1D&D already answered this whole discussion effectively by saying don't allow checks where the DC is 30 or higher right? (Also: never ask for a roll when the DC is 5 or lower). Huge numbers of people seem to have missed that entirely. This entire discussion seems to have missed that, in fact.

No, we didn't miss that and it was brought up early on. I think it's pretty much just accepted at this point. What is being discussed right now are ways of gating rolls that fall within the 5-30 range and the appropriateness of doing so.

 

[MarkB]

Because apparently, the way it was written before was confusing for DMs and players, because "do natural 20s automatically succeed on an ability check?" was an extremely common question on 5e forums.

It's not just a disambiguation though, it's a deliberate change to the rule. If you're gating a player's ability to roll a check behind "must be able to meet the DC on at least a 20", then you're not implementing auto-success on a natural 20.

 

[Minigiant]

Indeed. Impossible knowledge check successes are a great way for the DM and player to devise some new color to the character's backstory to explain why they happen to have that particular oddball piece of knowledge.

I think almost anyone with a real life specialty in any type of knowledge (be it from education, career, or hobby) has both a sense of knowledge that there is actually no chance a non-specialist would possess and the experience of encountering a non-specialist who (at least sort of) knew some specific facts within their specialty that they never expected a non-specialist to possess. It is useful for DMs to reflect on those experiences in deciding when to let non-proficient characters roll on knowledge checks specifically. I think if a fact is interesting enough to be relevant to an adventure, a five percent chance of a non-specialist happening to have picked up at least a clue or hazy hint of that fact somewhere in their decades (or for some characters, centuries) of varied life experience is not nearly as unrealistic as it seems at first blush.

The issue comes when the action is so specialized or lore is so secretive that the nonspecialist could not have perform the action nor happened across the info.

Therefore the fiat of the DM to determine the impossible becomes more important.

It's not a bad thing but it's a new thing to think about.

 

[Lanefan]

Because I don't have to know them.

DM: "If you are proficient with Arcana, give me a roll."

I don't care what your modifiers are. I just excluded everyone without Arcana regardless of their modifiers.

Which may mean you've just unfairly excluded a PC whose modifiers from sources other than Arcana would be enough to give a chance of success. I think that's the issue here; that if someone legitimately has a chance of success then it's unfair to arbitrarily deny that chance.

 

[Maxperson]

Which may mean you've just unfairly excluded a PC whose modifiers from sources other than Arcana would be enough to give a chance of success. I think that's the issue here; that if someone legitimately has a chance of success then it's unfair to arbitrarily deny that chance.

Modifiers aren't enough for everything. I'm a smart guy and have a fairly good int bonus and have an interest in history. That doesn't compare to what someone who has a degree in history. He will know a lot of things that I don't, even if his proficiency bonus means that he and I have the same plus.

It's not at all unfair to exclude those who are not proficient from some rolls.

 

[Bill Zebub]

All five PCs are rolling. Under the new rule, one PC out of five needs to roll a 20 to succeed, and everyone succeeds on a 20. There’s a 22.6% chance that at least one will do so.

And let's say that one of them has a +10 to the check— a cleric with a +5 Wis mod, plus a proficiency bonus of +5 at level 16. Everyone else's mods are lower. Under the old rule, that cleric had a 5% chance of success, and no one else had a chance (unless they boosted it with bardic inspiration, etc., if the DM permitted that). Under the new rule, the cleric has the same chance of success as everybody else. Her stats and skills do not matter.

Unless the DM rules that it’s not possible for anybody but the cleric.

 

[Levistus's_Leviathan]

It's not just a disambiguation though, it's a deliberate change to the rule. If you're gating a player's ability to roll a check behind "must be able to meet the DC on at least a 20", then you're not implementing auto-success on a natural 20.

The 5e DMG says that if a d20 test would be outside the range of a PCs abilities, there's no point in having them roll. The design intentions haven't changed at all. They're just changing the wording to make it more clear what they want to have happen.