You can ask both guards if an item is an item. "Does this cup contain fluid" would work, it doesn't have to be a dead guy.

no because the question was which door would the other person say is safe, they both point to the not safe door

I wish our DM had real-life message to telepathically convey stuff to just one person. In my group there would be literal zero chance of the others not listening to me if I ever threw a “hmm why is that wire there”, because they would’ve heard the dm either tell me due to passive perception or had me throw a roll and then tell me. So they know it’s a trap no matter if I want to rp it. Every time I get frustrated and question it, there’s thistle guy who always has the reasoning and justifying at hand why they would know to do the right thing and to be fair they kind of make sense always, but there’s zero chance he’d come up with that just by my rp line alone without knowing for a fact it’s a trap. I think that’s the worst kind of meta gaming. They are fully blind to the meta gaming there and just do it by instinct. And when you try and question, they always have a defense ready, even if it’s so wildly specific and unlikely but you can’t really fault it because they’re not stupid, the justifications hold, it’s just that the only way they habitually generate them is because they know what I know despite they couldn’t in-game know. Like I’ve occasionally just left the thing unsaid in-game out of frustration and just reason to DM that there’s so much going on, my focus instantly switched to another thing and I forgot because I’m not very smart. So we all know there’s a trap but now nobody has told this to the others. What do they do? The one guy fucking always comes up with some shit like “hmmm be wary, they must’ve laid traps here, hey you with good investigation, please look around and see if there’s one in this specific place for some reason” and the rolls of course often succeed because they always choose to best one to solve that. But from rp perspective, we’ve walked this path for a while, and this thought only came up now, that it might be trapped? Just right now when you know, outside of the game, that there’s a trap? I call bullshit and it frustrates me so much, there’s very little chance of anything interesting ever happening in-game because we seldom miss anything or do the wrong things, because “somehow” we always happen to do the right things no matter who notices things in-game or rolls or whatever, no matter how much any of us attempt to rp it, somebody just meta games it without it being explicitly or admittedly meta gaming and gets all defensive when questioned and because they now know everything, can figure out an explanation the DM can do nothing but accept because it makes sense, now that they know to pull the right shit out their ass. Ugh. It’s not even a big deal, our group is fun and the adventuring isn’t bad, these things don’t happen often enough for it to really affect things, but god do I hate it. This ended up being a rant, I didn’t even know how much I get frustrated with it until I just now read this back. Jesus…

JAJAJAJAJAJJAJAJAJAJJAJAJAJAJAJAJJAJAJAJJAJAJJAJAJJAJAJAJAJJ almighty

Well, obviously. But a barbarian might have a preference.

I think you mean HEY, WHAT'S UP?

You should even specify “path to the castle”, because there isn’t _technically_ a “correct” path.

No because them pointing at a door is answering a different question than the one that was posited in the question.

yeah, it could be the liar guard's desire or prin to send you down the deadly path. to him that could be interpretated as the correct path. especially if these are automatons working off of some machine logic. like, they don't even need to be out to get you, that's totally something that bad code could do on accident.

The liar responds "I don't know"

And the surviving guard will most definitely answer a 2nd question despite the rules.

This puzzle was used in more than one place than in Labyrinth. I played video games where they had that puzzle (Ultima 6 had that).

The question we ask if "What would the other guard say if I asked him which door is the good one?" Liar says Bad Door Truther says Bad Door Now, for their answers to update, they would have to ne answering the question, "Which door would the other guard say if I asked him 'Which guard would the other guard say is the good door?'" We want a guard to answer "What would the other guard say is the good door?" Regardless of how they answer our "outer" question, the answer to the "inner" question ("which is the good door?") doesn't change. Liar doesn't care that Truther would say that "Liar would say the right door is the good one," Liar is being asked how Truther would answer "Which door is the good one". I know I basically just said the same thing three times. My brain isn't working to break this out the elegant way I can't quite assemble. But hopefully some part of all this helps. The crux is that the question that they are imagining the other guard's answer to is not the same question they themselves are being asked.

What is the quest was to die asap. And everyone the party meets just refused to kill them?

Now let’s make it a little harder. You have three guards: one tells the truth, one lies, one answers randomly. The guards understand you, but only answer either “da” or “ja”. One means yes, one means no, but you don’t know which is which. You get to ask each guard one question.

Give them a paradox by encoding the other two's potential responses into the question (similarly to the two guard solution, but this time the random response is included). If they are able to answer, then you asked the random one, because the liar and truth teller have no idea what the random one would answer so can't answer only yes or no without potentially violating their truthiness rule. This isn't to solve the puzzle but to see what the other two would do in that situation. If I figured out the random one with the first question, I'd use the 2nd to ask the same thing of one of the others. Then, if it's still 2 doors, the two guard solution will work on the last one to figure it out. But if the first guard asked explodes or something when asked, I think that there wouldn't be enough questions left to find both the random guard (which I believe you have to do first) and the door. Though if you change the question to only ask about one other's answer instead of both, you'll be able to find both the random guard and the safe door. Though hopefully the whole setup isn't a lie and everyone present is a strategic liar that wants you dead. Imagine doing one of those riddles and when you step through the door you notice both doors lead into the same room whose walls now seem to be closing in and the last thing you hear is one of the guards asking another why riddles seem to get people to let their guard down anyways.

I was thinking: he could lie about the guard but not about the safe door, so he would still be lying. But that's technically a half-truth, which this particular guard isn't capable of. So you're absolutely right, thank you.

Yes, you're right. I was thinking he could lie both about what the other guard would have said as well as what door leads to doom, but the other guard can only give one truthful answer.

That last question is ambiguous enough (in this specific scenario) that either answer would work. It's both true that the other guard can't tell her something happened (due to being dead), while the other guard would have said that something did happen if he had been able to. So it's a meaningless question but the wife doesn't know that since she doesn't know the guard is dead. Which just adds another layer to the joke lol.

Yeah, I agree that having a secret communication channel between the DM and players is good because it goes deeper than just meta gaming: there's also meta meta gaming. As in you hear a piece of information that your character would have no way of knowing and this piece of information makes the correct tactical option obvious. It might not have been as obvious before, but now that you know, you can't unknow it (at least not without an even more severe disruption to the game). So does that mean you can't pick that now obvious option to avoid meta gaming? What if your character probably would have chosen that option anyways? Same thing for trying to do something that would reveal that information to your character, would your character have done it without the information? Should you just pick a bad option now because any good option is meta gaming? I don't think there is a good solution once anyone knows about the information. Hell, even your barbarian's decision to not say anything could be considered meta gaming because you were doing it in response to how the other players were acting and justified it afterwards just like they are doing. *Avoiding the meta gaming option is still meta gaming*, it's just from a place of not being able to help but meta game. It's like playtesting magic decks against another one of your decks alone. Sure, you can see some things like how well the mana ramp works, how big of a threat you can get on the board relative to your opponents, but when it comes to interactions, you know exactly what spells you should counter or ignore, what might happen if you choose to block or let an attack through. There's no tactical surprise or bluffing, which can both play a big role in the game. When I DMed, I liked to have some rolls from the players ready ahead of time, because I found even "roll a spot/listen check" gave away too much information on its own. Pass or fail, it was a signal to start doing some active searching because there's something of interest in the vicinity. So instead I'd just use the early rolls and cross them off my list as the players made passive sensory checks and only mention anything if the roll was high enough. Then notes can be passed with the information to those who know it, plus extra nothing notes sent from time to time, maybe with a promised reward if they don't say it's a nothing note so the meta gaming that results just wastes time and discourages people just reacting to notes.