When the heroes enter a combat and want to know information about their enemies (keywords, strengths, weaknesses etc) would the ability check require an action or is this a free action?

I have read Does D&D 5e have a rule for character knowledge about monsters? but it only discusses which skills to use, not what actions it would take.

My group thinks it should be a free action as you can ask your knowledge while you act. I think with 4 people in the group at least one always rolls high enough to get serious information. And of course it will happen at the start of every battle because it doesn't cost the PCs anything.

I am planning (if it's for free) to do either a group check or a passive check (like perception or insight, just with the appropriate skill), but I still think giving away information for free that can seriously change the outcome of the battle is quite cheap. Especially in Out of the Abyss, where you have many monsters with special features.

So - how does giving out monster information during combat work, action wise?

  • \$\begingroup\$ Thanks for the input (esp the Battle Master feature, which I hadnt recognized yet) ! I guess I will take the free action but with certain restrictions (proficiency, or higher DC). \$\endgroup\$
    – Anthean
    Mar 24, 2016 at 8:18

8 Answers 8


Remembering is not an action

Beholding a creature and trying to recall information about it would not take an action. Perhaps it might be considered "interacting with an object or feature of the environment" (PH 190) - which a character can do once on its turn without expending an action.

But there's another way to preserve a little mystery about your monsters…

Explanations are actions

If one character recalls the creature, that doesn't mean all characters have. You could slip a note to the character(s) who succeed the knowledge check. If they share more than "brief utterances and gestures" (PH 190) about the monsters, then it's rules-as-written to determine the character spent its action.

Player Knowledge vs Character Knowledge

If you've got power gamers at your table, it's also reasonable to insist the players don't abuse player knowledge. If the players have the MM memorized, and a player shares the monster's name, you can rule that the character spent its action giving the characters the knowledge the players already have.

(Alternatively, just change details about the published monsters yourself.)


As quoted in the question you linked to,

PHB, page 177 - 178, Intelligence Checks

Your Intelligence (Arcana) check measures your ability to recall lore about ... the inhabitants of planes

It shouldn't take an action to remember something.

But, you can't remember something you don't know. If the creature is less well-known, raise the DC.

If the character succeeds on their check, you would tell them what this creature's special abilities are. But not things that may vary by individual - their exact HP, AC, and so on. They are remembering what they know about a typical member of the species (eg, humans); not this exact one (eg, John Smith).

But, just because one character knows something, doesn't automatically mean the whole party knows. That character will have to let the others know. They can make a few words or gestures as a free action - eg "Avoid its gaze", "It breathes acid", or "Don't use blades". If it takes more than that, then they'll need to use an action to do so.

  • \$\begingroup\$ Excellent answer. The only thing I think is missing is perhaps the last paragraph in the question, about group rolling and feeling like the group always knows something about the encounter because they have 4+ rolls for the check. \$\endgroup\$ Mar 23, 2016 at 14:41
  • \$\begingroup\$ @Premier, I have an answer to that in point #3 of my answer - Adeptus, feel free to incorporate it into yours if you think it's useful. \$\endgroup\$ Mar 25, 2016 at 2:27
  • \$\begingroup\$ @PremierBromanov the only problem I have with that is that just because the whole group can make a check, the whole group wouldn't instantly know the answer. The information would have to be shared with the members of the group and that would have to take an action on someone's part. \$\endgroup\$
    – Escoce
    Mar 25, 2016 at 18:14
  • \$\begingroup\$ @Escoce you're right, the group wouldn't know. Whoever rolled high enough knows. It's up to the players to avoid meta-gaming and up to them to convey the information (or not) in character (which they can't do if it's not their turn, usually). Or, reveal the information in secret, whatever you need to do. \$\endgroup\$ Mar 25, 2016 at 22:55

In the absence of specific rules saying otherwise, I would say it doesn't take an action to recognize a creature and remember something about it. The rules on "Other Actions" (PHB190) do suggest putting reasonable limitations on how much can be relayed to the other party members without using an action, though:

You can communicate however you are able, through brief utterances and gestures, as you take your turn... The DM might require you to use an action for any of these activities when it needs special care.

However, if that still seems too easy, there are several plausible ways to make it tougher:

  1. Setting an appropriate DC - rare creatures should have a high DC, perhaps 20, and horrors from the Beyond could be 25 or higher if no mortal has ever seen one and lived.
  2. Making it take time. You don't need to spend an action, but it will take a few seconds of observing the creature for you to recognize it (i.e. roll only after your first round).
  3. Depending on the monster, ruling that only those who have studied the skill (i.e. with proficiency) are allowed to roll at all. Anyone might have heard somewhere that different dragons breathe different substances, or skeletons can be easily crushed, but some knowledge is only available to the experts. This eliminates the statistical advantage of rolling four times. (And if 3-4 party members are proficient in the appropriate knowledge skill, it's very likely one of them would know something; let their abilities be meaningful.)
  4. Limit what you reveal to what someone in-universe could plausibly know. I would probably never give out a monster's AC, or any but the broadest glimpse of HP, unless the world contained a powerful guild of determined statistician-adventurers. Instead say "Its scaly hide looks tough to penetrate" (high AC), or "Legends say it cannot be wounded by any ordinary blade" (immune to non-magic weapons), or "They say he is no stronger than a mortal man, if you can but resist his hypnotic voice long enough to find out" (low-medium HP and uses Enchantment spells).

I've usually used (or been in campaigns where the GM used) at least #1, #3, and #4, and everybody was fine with it. If your players are more interested in RAW and tactics than narrative realism, you may have to rely more heavily on #1 to satisfy them.


Depends on your familiarity with the creature.

It comes down to reasonable expectations of what you know about a creature. If your group has battled this foe a lot, or they are a common enemy type in the area, then it's a simple knowledge check. This can even be bypassed if it's something that's reasonably common (in Forgotten Realms for example bugbears, orcs and goblins would be extremely well known, common enemy types.)

If it's something you're trying to study in combat to discern patterns or to sense it's vulnerability, remaining health, strengths, resistances, etc; then you would have to do an active check because you're specifically looking for things in the midst of combat.

Oh and if it's something the DM has modified, it may act slightly different so you may get erroneous information. Don't take anything for granted. That's how many a hero has met their untimely demise.


So you remembered a fact, which happened instantly, so you need to get that info to your colleagues. Most of the time, a command like "Target the Dragons Eyes!" is enough, especially if you trust each other.

But sometimes you need to explain a thing more thoroughly like "Target the eyes, but dont hit the heavily armored Eyebrows, that will only make him angry, and then he will spew flames at us, then we're all going to die, and this dragon will then conquer the world, oh my god i failed my Morale Check aaaaaaaaah!"

Something like that.

Remembering something is instant but conveying this information may need one or more Actions.


Short Answer: Free action, but recommended to scale DCs for more info. House Rule: Action gives them advantage. More than one player rolling increases the difficulty.

Long Answer: Remembering something is instant in most situations, so by default this would be a free action. However, most people won't remember many details about anything. Spending more time trying to remember would possibly allow them to remember more.

There also shouldn't be a single DC for all the info. Depending on the creature, and how well known it would be, I give it a base DC, then increment the DC for more info:

  • Base DC: Monster type, race, and size plus any well know info about said type or race (EG: were-creatures are vulnerable to silver, Drow can see in the Dark, dwarves are short, etc.) (This check should be relatively easy)
  • Base DC + 10: The AC and HP range (AC is between 10 and 15, HP is between 20 and 25) plus a bit more info about the creature itself ( Is it a spellcaster, etc.)
  • Base DC + 15: Specific AC and HP plus specific resistances and vulnerabilities.
  • Base DC + 20: Most everything else that could realistically be known about the creature.

The Base DC should be easy (between 5 and 10) but the final DCs (between 20 and 30) should be hard enough not to be received regularly. I also give bonuses for specific situations (Dwarves should know more about goblins that most). This also means that the Battlemaster Lvl 7 benefit is no longer worthless, as the information gained would require a check with a DC of 20 to 25, in a skill that Battlemasters typically don't have trained.

As a house rule, If my players spend an action preparing, I give them advantage on the roll.

As for the group roll issue: Once the first player has done his check, another player can also try, but the DCs are all just a bit harder (+2 to +4). If a third player tries then I increase the DC a second time (+4 to +8) and so forth. This helps represent that if the first couple players don't know stuff, the rest of the party probably won't either.

  • 2
    \$\begingroup\$ This doesn't accurately reflect 5th Edition's bounded accuracy. When a DC of 30 is "nearly impossible", adding +4, +10, +15, or even +20 to a base DC is WAY out of the ballpark. \$\endgroup\$
    – Discord
    Mar 24, 2016 at 18:11
  • \$\begingroup\$ @Discord That's the point. It SHOULD be nearly impossible to know "Most everything that could realistically be known about the creature." Players should only really know the AC and/or HP of a creature occasionally, which is why it has a DC of 20 or so. The AC/HP ranges should be a bit more common, thus the DC of 15 or so. \$\endgroup\$
    – Patrick vD
    Mar 24, 2016 at 18:28

In the Actions in Combat section you have a SEARCH action (PHB p. 193) which includes a description with Wisdom (Perception) check.

When you take the Search action, you devote your attention to finding something.

It is probably on purpose that this is quite vague.

I think that what you are describing is a Search action. The characters wants to see whether the creature has scale that increase its AC, has teeth dripping poisons, has large ears and piercing eyes... maybe a focus symbol that could mean the creature can cast spells as a wizard or a cleric.

However, I would not give my players any detailed information such as

"Oh! By the way this mummy is immune to non magical weapons."

because such information cannot be inferred until you notice that your weapon had no effect (you will know if it did not have any effect on a hit, however, if it does only 50% damages, you probably do not know right away, you may notice after a few hits though.)

I had a Paladin use a normal weapon to attack Gargoyles and noticed nothing happened. He then used his reaction to send radiant damage, nice move!

However, in all cases, the type of information you want to given for such a check should be a more detailed description of the creature and not technical information. For example, whether the skin is not flesh like, but actually scales, making you think it will be tougher to hit than a bear or such. You should not give information such as this monster has an AC of 15.

Actually fighting the monster would tell you what the AC is after a few hits that succeeds you should have a pretty good idea. Any other aspect would be the same.

As noted by nitsua60, a Battle Master fighter has to reach level 7 before it can know whether things such as the creature AC, Strength Score, Current Hit Points... are inferior, equal, or superior to his own abilities (PHB p. 73-74) and not only that, it takes him one whole minute to do so. So giving a totally free information (i.e. no action, information that should not be easily perceived) to players is certainly not a good idea!

  • 3
    \$\begingroup\$ Do you think it's worth drawing a comparison with the "Know Your Enemy" Battle Master L7 feature (PHB pp.73-74)? It seems like, if not careful, one could easily moot this. (OTOH, in my opinion the Champion's and Battle Master's L7 features are really underwhelming of their own accord, so mooting one of them may not be the fault of a good scheme along OP's lines. Just thought it worth considering something in existence that already achieves some of what OP wants.) \$\endgroup\$
    – nitsua60
    Mar 23, 2016 at 1:14
  • \$\begingroup\$ What I am trying to say is that the players can be given more details about the creature description. Personally, I show them a picture whenever I have one. That generally gives them an idea although they do not always know whether a creature will transform them to stone or has a breath weapon. But they find out quickly enough when in combat... \$\endgroup\$ Mar 23, 2016 at 1:44
  • \$\begingroup\$ What you're describing is one way of getting info, but based on the wording of the question and the linked question, I'm pretty sure they're talking about recalling existing knowledge like Arcana, not observing with Perception. \$\endgroup\$ Mar 25, 2016 at 11:41

Using a skill for knowledge is for determining if you know something or not. Not for "getting information on a creature". Therefore, it should not take an action, even though the book does not say that explicitly.


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