Adjudicating Invalid Actions

[PhoenixPhyre]

So some of the more contentious threads recently have got me thinking. When and how should a DM declare an action invalid?

By invalid I don't mean ineffective (like with damage immunity). I mean that the action as stated cannot happen due to being outside either the fiction or the rules. For example:

Swinging off a chandelier when the party is 200 miles from the nearest chandelier.
Casting Charm Person with a declared target of a dog.
Casting a spell as bonus action when the casting time is an action.
Attacking a target that the character does not know is there (due to vision, stealth, etc)
etc.


I can see a few options (in order from nicest to nastiest for the character):

Intervene at action declaration. No resources (actions, spell slots, ammunition, etc) wasted.
Intervene at action declaration. Action wasted, but nothing else.
Intervene after declaration. Resources burned and player learns why the attempt failed.
Narrate as usual, but no effect other than resources wasted.


My personal feelings? I tend to default to the first two for anything that the character would know as a competent adventurer. It's impossible to swing off a chandelier that doesn't exist (and the character knows that it doesn't exist). Generally I'll take the second for things the player should have known better (like using a spell on an invalid target). The third is my default for major illusions (and similar effects) and cases where the spell or action would generally work but not in this specific case (casting cure wounds on a disguised undead). I don't think I have a use for the last option.

Thoughts? When and how do you declare an attempted action invalid? What effects does it have?

[Laurefindel]

Usually, I just tell the players that they can't do that because [reason]. There are no chandelier, you already used your action etc. I simply tell the players to rephrase their action.

Now casting a spell at the wrong target is not an invalid action. You can do it, just don't expect it to work. I'm ok with players not knowing every single spell be heart; when something like that happens, I just tell them that their character would know it and allow them to cast another spell instead.

As for the effectively invisible target; if the characters have a good reason to think that the target is there (because they are guided by a friend, because they saw a spell originate from there, becasue they can clearly hear it etc.), they are allowed a swing, albeit at disadvantage as per the invisible condition. In doubt, they have to use the search action first.

[JellyPooga]

In cases like these, I too would opt for either of the first two options you present.

In the second case, where it applies to invalid targets, I'd generally allow a Lore roll (Arcana, History, Nature or Religion) to avoid losing the action too. Players don't know what Characters know, so let the dice (and skill mods) decide if the action (and potentially spell/other resource) would be wasted.

If it's a blatant brain fart, then I'm more forgiving than if it's willful ignorance on the Players part. If it's a genuine lack of Player knowledge (e.g. assuming a Unicorn is a Beast instead of a Celestial), then use the Lore check. If it's something both the Player and Character know full well (e.g. they've previously made a Lore check to determine the validity), then waste both action and resource (usually a spell slot).

In short; be forgiving...up to a point. If a Player's being an idiot, then let him know what he is.

[BW022]

It would depend on how/why the player might have declared their intent to take the action.


Where they not paying attention when the party left the city and they still thought they were in the inn?
Are they a new player who didn't know charm person doesn't affect animals?
Are they knowingly trying to cheat the rule system and get extra actions in?
Maybe they do know where the creature is? Perhaps they have some ability you aren't aware of... say blind sight?


Start by asking. Why do you think your character is able to do that? This may involve explaining to them that they left the inn a long time ago, that charm person don't affect a dog, give them a chance to let you know that they have some ability you overlooked, etc. Ask follow-ups until you have determined if this is a mistake, rules misunderstanding, just too new to the game, you didn't factor in the character has a bat familiar, etc. In most cases, they'll switch actions if they realize it isn't possible.

If they still attempt an action (which isn't against the rules but makes no sense), either tell them it isn't possible or let them know that that their character doesn't think it is possible. If they insist... then allow it to happen but fail.


"You leap into the air, grab what you think in a chandelier and fall on your butt when you grab the air."
"You cast the spell and target the dog. You feel the magical energy leave you, move towards the dog, and then dissipate into the air around it. The dog wags its tail and sniffs. One spell slot is used."
"You hurriedly try casting a spell in a much shorter period of time. The magic forms around your hand but as the symbols aren't completed correctly the magic just flows in random directions. One spell slot is used." (If it got to that point)
"Please roll a d8 and a d12. You target a random square where you think the creature might be. The arrow sails across the forest trees and scares some birds in the large oak tree you fire the arrow into."

[Giant2005]

You intervene at the point that the character should realize.
The character would know that there is no chandelier to swing on, so you tell him so prior to him wasting his action.
The dog looks too much like a human for the character to know that it was a dog prior to using their action; so you tell them that the spell failed after the action and limited resources have been used (I know the dog doesn't look like a human and ordinarily the character would know that, but this is a really, really human-looking dog for the sake of the example).

[Plaguescarred]

Each situation is unique but in general i try to tell a player in advance that his desired action is invalid and the reasons it is so. I try not to screw with with a PC's action too much and if a situation could lead to a potential waste of action by being invalid, i will also try to warn the player that there's a risk he waste his action before he attempt to do so because i believe in DM transparency whenever possible.

[Shining Wrath]

If the player attempts to use something that's not there, like a chandelier, I'd ask them "What chandelier"?
If the player attempts to cast a spell on an invalid target I'd probably tell them in advance - or one of the other players would.
Casting a spell as a bonus action when the casting time is an action, tell them in advance. Again, one of the other players is likely to say something - we have a lot of knowledge and a non-adversarial table.
Attacking a target they don't know is there - well, now, that gets interesting. How much of a lack of knowledge is there? If my wizard is deathly afraid of Intellect Devourers, and throws Fire Bolts into shadows because he "thought he saw something", that's role playing. If it so happens the targeted space contains a sneaky drow rogue, he might hit it.

[JakOfAllTirades]

I'd make a sincere effort to inform the player/character the action is pointless before I've passed the point of violating Wheaton's Law.

[rollingForInit]

I always intervene before any resources are burnt if it's something the characters should definitely know, or if it's something the players should know. It could be that the players misunderstood the environment, for instance, and a character wouldn't try to swing off a chandelier that isn't there. Makes no sense, no action should be wasted. A player might also attempt to cast Charm Person on a dog, because they misread the spell description. In that case, I'd remind the player that it won't work. In many cases the character would know this as well.

Really, I can't see many reasons to do anything besides that. If you do, you're basically punishing the player for not remember every rule by heard, or punishing them because you didn't describe something clearly enough.

Only situation I'd do otherwise is if some form of deceit is going on in-game. The chandelier in the ceiling is actually an illusion, or the person a player cast Charm Person at is an angel in disguise that is really immune. But then, those wouldn't be invalid actions, just actions with different results than anticipated.

[Vogonjeltz]

So some of the more contentious threads recently have got me thinking. When and how should a DM declare an action invalid?

By invalid I don't mean ineffective (like with damage immunity). I mean that the action as stated cannot happen due to being outside either the fiction or the rules. For example:
•Swinging off a chandelier when the party is 200 miles from the nearest chandelier.
•Casting Charm Person with a declared target of a dog.
•Casting a spell as bonus action when the casting time is an action.
•Attacking a target that the character does not know is there (due to vision, stealth, etc)
•etc.


I can see a few options (in order from nicest to nastiest for the character):
•Intervene at action declaration. No resources (actions, spell slots, ammunition, etc) wasted.
•Intervene at action declaration. Action wasted, but nothing else.
•Intervene after declaration. Resources burned and player learns why the attempt failed.
•Narrate as usual, but no effect other than resources wasted.


My personal feelings? I tend to default to the first two for anything that the character would know as a competent adventurer. It's impossible to swing off a chandelier that doesn't exist (and the character knows that it doesn't exist). Generally I'll take the second for things the player should have known better (like using a spell on an invalid target). The third is my default for major illusions (and similar effects) and cases where the spell or action would generally work but not in this specific case (casting cure wounds on a disguised undead). I don't think I have a use for the last option.

Thoughts? When and how do you declare an attempted action invalid? What effects does it have?

If the player is mistaken about the availability of whatever, I inform them of that.

i.e. There's no chandelier. What did you want to do instead?

If that involves them re-doing their movement based on their new understanding of what is actually going on in the scene, that's fine. It wouldn't be fair of me to penalize the player for not having a full spatial awareness of the scene if we're just using theater of the mind.

If the criteria for casting the spell are such that it's obviously not right (i.e. it's a Dog instead of a humanoid), then I'd just let them know that it doesn't work on beasts like dogs. If the player was like "I know, but I still want to try casting it" I'd just inform them the spell fizzles and they've expended a spell slot.

The latter two examples are simply informing the player.

First that it requires an action. Also, it's worth noting there's no bonus action until there's an ability with a bonus action that uses it. And there's only one per turn at best.

Second, remind them that they have forgotten their character's knowledge is not the same as their player's knowledge.

[Ruslan]

Open question - how do you deal with this:

DM: As you navigate the mountain pass, a crossbow bolt whooshes past your ear, nearly hitting you. About hundred-and-twenty feet upslope, you see what appears to be a very small humanoid, reloading a very large crossbow. What do you do?
Bob (player): I charge and hit it with my sword!
DM: You rush your full extend of movement toward the enemy, closing sixty feet of distance. You are still sixty feet away. Mindy, your turn.
Mindy (player): I shoot an arrow at it, then move behind the nearest boulder to take cover.
Bob: Wait, did you say hundred and twenty? I though you said twenty.

[Vogonjeltz]

Open question - how do you deal with this:

DM: As you navigate the mountain pass, a crossbow bolt whooshes past your ear, nearly hitting you. About hundred-and-twenty feet upslope, you see what appears to be a very small humanoid, reloading a very large crossbow. What do you do?
Bob (player): I charge and hit it with my sword!
DM: You rush your full extend of movement toward the enemy, closing sixty feet of distance. You are still sixty feet away. Mindy, your turn.
Mindy (player): I shoot an arrow at it, then move behind the nearest boulder to take cover.
Bob: Wait, did you say hundred and twenty? I though you said twenty.

Presumably this happened in the span of about 30 seconds real time, so I'd ask Bob if he wanted to do something different.

[PhoenixPhyre]

Open question - how do you deal with this:

DM: As you navigate the mountain pass, a crossbow bolt whooshes past your ear, nearly hitting you. About hundred-and-twenty feet upslope, you see what appears to be a very small humanoid, reloading a very large crossbow. What do you do?
Bob (player): I charge and hit it with my sword!
DM: You rush your full extend of movement toward the enemy, closing sixty feet of distance. You are still sixty feet away. Mindy, your turn.
Mindy (player): I shoot an arrow at it, then move behind the nearest boulder to take cover.
Bob: Wait, did you say hundred and twenty? I though you said twenty.

If Bob is relatively new or doesn't have a history of pushing the limits, I'd warn him before narrating the result:
DM: You realize that you can't get there in one turn?

Otherwise, I'd roll back to give Bob another chance. Once or twice. After that, he's gaming the system and needs to stop. Then I'd tell him "This is becoming a habit. No dice." and move on with Mindy's turn.

I'm not a fan of adversarial "gotcha" DM styles, but I think an important aspect of the DM's job is to maintain order and teach proper behavior.

[Plaguescarred]

Open question - how do you deal with this:

DM: As you navigate the mountain pass, a crossbow bolt whooshes past your ear, nearly hitting you. About hundred-and-twenty feet upslope, you see what appears to be a very small humanoid, reloading a very large crossbow. What do you do?
Bob (player): I charge and hit it with my sword!
DM: You rush your full extend of movement toward the enemy, closing sixty feet of distance. You are still sixty feet away. Mindy, your turn.
Mindy (player): I shoot an arrow at it, then move behind the nearest boulder to take cover.
Bob: Wait, did you say hundred and twenty? I though you said twenty.As a DM i'd tell Bob that he can move 60 feet but the enemy will be out of reach being still 60 feet away, rather than resolving (half) the action he wanted to achieve and pass to the next.

If by any chance i overlooked it though and did as described, i'd ask if Bob wants to change what he did.

[pwykersotz]

You intervene at the point that the character should realize.
The character would know that there is no chandelier to swing on, so you tell him so prior to him wasting his action.
The dog looks too much like a human for the character to know that it was a dog prior to using their action; so you tell them that the spell failed after the action and limited resources have been used.

This is the best answer so far, in my opinion. Players have brainfarts, but if the character would obviously know something, it should get corrected at that point. But if the character wouldn't realize it yet, I wouldn't correct it. This method assumes you aren't requiring skill checks for trivial matters.

[Plaguescarred]

I wouldn't let a PC waste an action and spellslot on a creature he can't even target with a spell in the first place, its a ''gotcha'' move not nice IMO. If the spell cannot target a creature as a DM i'd tell the player.

[pwykersotz]

I wouldn't let a PC waste an action and spellslot on a creature he can't even target with a spell in the first place, its a ''gotcha'' move not nice IMO. If the spell cannot target a creature as a DM i'd tell the player.

I used to fall on this side of the fence, but I've since changed my view. I'm generous with detail and if there's any ambiguity, it's because the players didn't look into it. If the players try to Charm Person the temple priest and it fails because he's a Deva and they didn't know that, I'm not going to let them play 20 questions with spell slots until they find the right one. Not for free, at any rate. This would only work in the kind of game where characters had nameplates of a sort, like in video or board games. Everyone knows the creature type because it's written RIGHT THERE. That's fine, just not so much the way I play.

On the other hand, if they know the priest is a Deva and attempt to cast the spell, I'd definitely remind them it wouldn't work. Their characters know better, and I hate gotcha moves too. But it's only a gotcha if it's some sort of entrapment. If the players decide to take action that is reasonable in character but is ultimately invalid, that's a great opportunity to deepen the story.

[Laurefindel]

(...) If the players decide to take action that is reasonable in character but is ultimately invalid, that's a great opportunity to deepen the story.

In which case it is no longer an invalid action :)

[Hrugner]

It sort of depends. Generally I won't let a player throw resources away, but I do let them take an action that reveals more information if it doesn't work. Casting charm person on the dog won't work, but it does let them know that the dog isn't a person disguised in some way. Swinging from non-existent chandeliers is not an action that can be started, I'd recommend other ceiling features if available, but otherwise stop the action.

For some things where the action is prohibited by rules but not reason, I'll give some partial result. With the charmed dog, he may be slightly more friendly, just not charmed. "Your spell sweeps through the dogs mind but can't act on him the way it would a human. You think with some research you could develop a spell that worked on dogs. This one seems slightly more pleased to meet you." Taking the wrong type of action, such as in the casting time example, would just be thrown back to the player.

[Plaguescarred]

I'm generous with detail and if there's any ambiguity, it's because the players didn't look into it. If the players try to Charm Person the temple priest and it fails because he's a Deva and they didn't know that,Well there's a difference between trying to charm person a deva mistaken for a humanoid and a dog which is obviously not one.


On the other hand, if they know the priest is a Deva and attempt to cast the spell, I'd definitely remind them it wouldn't work. Their characters know better, and I hate gotcha moves too. But it's only a gotcha if it's some sort of entrapment. If the players decide to take action that is reasonable in character but is ultimately invalid, that's a great opportunity to deepen the story.Right in such case i'd probably tell the player the spell he wants to use is when attempting to charm a humanoid and that the dog is a beast as it easy to forget these details. Now if the player after that tells me he still wants to (in case its masked by illusion or whatnot) then i'd let it try and waste it but he would have been warned at least.