# IF you're allowing a PC to roll, WHEN does autosuccess matter?

#### Jfdlsjfd

##### .
We are told that the GM only asks for a D20 test when the outcome is in doubt (ie, there is chance of success and a chance of failure). We are also told that a natural 1 is always a failure, and a natural 20 is always a success.

So, under what situation would a nat 20 be a success without the "autosuccess rule" AND the GM asked for a roll anyway? If say, he determines that a character needs to roll 27 on the D20 to succeed, he's supposed to not ask for a roll. So no possibility of rolling 20. If there is a possibility of success, 20 will already include a success.

Same, in reverse, with 1.

EDIT: changed the title to show that my question wasn't related to the case where the DM disallows a roll altogether (it was a side thought) but to WHEN (and in that case HOW OFTEN) does the "auto-success on 20" change the outcome of a task.

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#### Peter BOSCO'S

Possibly the "outcome being in doubt" will vary depending on who is acting? Does WOTC expects every DM to have every PC's sheet memorized?

#### Bill Zebub

##### “It’s probably Matt Mercer’s fault.”
There seems to be some confusion about the order of operations between the DC and the idea of "automatic failure/success".

The DM determines whether an attempted action will succeed or fail NOT by computing the DC and then figuring out if it's possible for the player to roll that high. It is determined based on the DM's judgment about the state of the fiction, possibly factoring in the character that will be making the attempt.

IF the DM concludes that it might succeed, but might not, then they set a DC and call for an ability check.

#### Parmandur

##### Book-Friend
We are told that the GM only asks for a D20 test when the outcome is in doubt (ie, there is chance of success and a chance of failure). We are also told that a natural 1 is always a failure, and a natural 20 is always a success.

So, under what situation would a nat 20 be a success without the "autosuccess rule" AND the GM asked for a roll anyway? If say, he determines that a character needs to roll 27 on the D20 to succeed, he's supposed to not ask for a roll. So no possibility of rolling 20. If there is a possibility of success, 20 will already include a success.

Same, in reverse, with 1.

The only way it makes sense is that the provision that "The DM determines whether a d20 test is warranted in any given circumstances is strictly defined by the following sentence, "To be warranted, a d20 test must have a target number no less than 5 and no greater than 30."

That means that:

1. If somehow, your can bring your save DC for your spells to 31, the recipient doesn't get to roll (saving throws are part of d20 test)
2. If the target number (note they don't use DC anymore) for neurosurgery is 30, so your Dexterous, skilled neurosurgeon can have a go at it, then any shmuck has the right to try it because the roll becomes warranted.

So, I don't see a situation where (a) the rules are adhered to strictly (b) there is a possibility of failure that despite the roll normally succeeding on a roll of 1(or failure even on a 20. But I might be missing something.
So, lwtsay the 6 Strength Wizard tries to qualify for the Olympics. He doesn't get a d20 roll, because he cannot succeed due to lack of proficiency. DC doesn't come into play. Of a character cannot do something, they can't roll a d20 Test. If they can roll the test, then they have a 5% minimum chabce of success.

#### Peter BOSCO'S

There seems to be some confusion about the order of operations between the DC and the idea of "automatic failure/success".

The DM determines whether an attempted action will succeed or fail NOT by computing the DC and then figuring out if it's possible for the player to roll that high. It is determined based on the DM's judgment about the state of the fiction, possibly factoring in the character that will be making the attempt.

IF the DM concludes that it might succeed, but might not, then they set a DC and call for an ability check.
Why on earth would the dramatic importance of something happening alter the possibility of something happening? This is not a novel, this is a game. Games have rules, and players who are at all good at math should, barring hidden information such as "there's a trap in that door" almost always be able to closely estimate the probabilities of any action before deciding if they will attempt that action. DM's who just change stuff because they of their "judgement of the state of the fiction" are wrecking the implicit social contract between the DM and the players.

#### Tales and Chronicles

##### Jewel of the North, formerly know as vincegetorix
Why on earth would the dramatic importance of something happening alter the possibility of something happening? This is not a novel, this is a game. Games have rules, and players who are at all good at math should, barring hidden information such as "there's a trap in that door" almost always be able to closely estimate the probabilities of any action before deciding if they will attempt that action. DM's who just change stuff because they of their "judgement of the state of the fiction" are wrecking the implicit social contract between the DM and the players.

''Ability Checks
An ability check tests a character's or monster's innate talent and training in an effort to overcome a challenge. The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results.''

''How to Play

1. The DM describes the environment. The DM tells the players where their adventurers are and what's around them, presenting the basic scope of options that present themselves (how many doors lead out of a room, what's on a table, who's in the tavern, and so on).

2. The players describe what they want to do. Sometimes one player speaks for the whole party, saying, "We'll take the east door," for example. Other times, different adventurers do different things: one adventurer might search a treasure chest while a second examines an esoteric symbol engraved on a wall and a third keeps watch for monsters. The players don't need to take turns, but the DM listens to every player and decides how to resolve those actions.

Sometimes, resolving a task is easy. If an adventurer wants to walk across a room and open a door, the DM might just say that the door opens and describe what lies beyond. But the door might be locked, the floor might hide a deadly trap, or some other circumstance might make it challenging for an adventurer to complete a task. In those cases, the DM decides what happens, often relying on the roll of a die to determine the results of an action.

3. The DM narrates the results of the adventurers' actions. Describing the results often leads to another decision point, which brings the flow of the game right back to step 1.''

There's no social contract wrecking happening here. The DM decide if the character's action in-fiction requires a roll or not.

A situation being impossible is not ''uncertain'', thus does not require a roll.

Not calling for a roll is as much of a DM's decision than calling for one.

#### Bill Zebub

##### “It’s probably Matt Mercer’s fault.”
Why on earth would the dramatic importance of something happening alter the possibility of something happening? This is not a novel, this is a game. Games have rules, and players who are at all good at math should, barring hidden information such as "there's a trap in that door" almost always be able to closely estimate the probabilities of any action before deciding if they will attempt that action. DM's who just change stuff because they of their "judgement of the state of the fiction" are wrecking the implicit social contract between the DM and the players.

When the DM specifies the TN and the consequences for failure, the player should have a chance to change their mind. At least that’s how I play.

#### Larnievc

The DM determines whether an attempted action will succeed or fail NOT by computing the DC and then figuring out if it's possible for the player to roll that high.
Is this how it works? A DM has to know the players’ bonus? I just set a difficulty in my head head and ask them to role ability+proficiency and tell them if they succeed or fail.

Who said we have to know their stats?

#### Larnievc

DM's who just change stuff because they of their "judgement of the state of the fiction" are wrecking the implicit social contract between the DM and the players.
Disagree. The rule of cool is part of being a hero. It’s not a game: it’s a story. And it’s the players and the DM’s jib to make the story satisfying.

Otherwise you may as well be playing Hero Quest.

#### Bill Zebub

##### “It’s probably Matt Mercer’s fault.”
Is this how it works? A DM has to know the players’ bonus? I just set a difficulty in my head head and ask them to role ability+proficiency and tell them if they succeed or fail.

Who said we have to know their stats?

Umm...no. Maybe you missed the big, all-caps "NOT" in the middle of what I wrote?

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