Ttdfjt

Tonight during our play session, we ran into an incident where a character immediately used a bardic inspiration after getting it (on their turn, but like it was the first thing they did). The bard's player was curious if he could give the character inspiration again on his turn. He was curious if the bard would know if/when someone actually uses the inspiration bonus.

During the game, we quickly decided "Yes, because it's magic and you are connected to that magic." But I was curious and looked up the info on Bardic Inspiration on page 53 of the PHB:

You can inspire others through stirring words or music. To do so, you use a bonus action on your turn to choose one creature other than yourself within 60 feet of you who can hear you. That creature gains one Bardic Inspiration die, a d6.

Once within the next 10 minutes, the creature can roll the die and add the number rolled to one ability check, attack roll, or saving throw it makes. The creature can wait until after it rolls the d20 before deciding to use the Bardic Inspiration die, but must decide before the DM says whether the roll succeeds or fails. Once the Bardic Inspiration die is rolled, it is lost. A creature can have only one Bardic Inspiration die at a time.

Nothing in that description says that the effect is "magical". Granted, I think it probably is magical and that we guessed correctly, but I am still wondering if there is an official ruling on this.

Does a bard know when a character uses their Bardic Inspiration?

First of all, there are no written rules explicitly declaring that bardic inspiration is magical, so we should not assume it is. In general (as reminded by @V2Blast in a comment), what is to be considered magical in 5e is described in detail on page 17 of the Sage Advice Compendium under the question titled "Is the breath weapon of a dragon magical?" and based on that description, it is hard to consider bardic inspiration as magical. This was also confirmed in a non-official tweet by Jeremy Crawford on December 3, 2015:

Bardic Inspiration isn't magical, unless a DM rules otherwise.

Likewise, there are no rules regarding the moment (or even the round) a bard recognizes the die granted to another being has already been consumed or not. Yet a bard should be able to grant an inspiration die again as the previous ones get consumed (as nothing is against it), so she should somehow be able to recognize that it has been used. How and how fast this happens seems to have been left to how the DM interprets the game's flavor. I would personally rule that the bard should be able to know immediately after it is gone, as long as she can see the target (perhaps the character is no longer visibly "inspired", ie. no longer showing the extra morale).

No, it's not magical. No, they wouldn't know when it has been used.

If bardic inspirations were magical it would say they were magical. This is an important distinction in 5th edition since the Antimagic Field spell would suppress the ability to use a bardic inspiration if it were.

A bardic inspiration is more like a pep talk. The bard gives the target a bit of motivation that they can draw upon in their time of need. Since there is no magic involved, and the bard doesn't need to be present or aware of the target when they use the inspiration dice, the bard would not know when it has been used.

Since there is no linked official ruling, it's up to the DM.

If I had to make a choice, I would base my decision around what inspiration does. Since I enjoy the story telling aspect of D&D, my explanation would go like this:

• 
  

  Ability Check

  
  
  

  
  

  Gorthar: "I get a running start and try to jump the gap."

  
  
  

  (rolls for Athletics, totals 14)

  
  
  

  The DM gives a hintful grimace.

  
  
  

  Gorthar: "I think I will use my inspiration now."

  
  
  

  (adds his d6 roll and totals 16)

  
  
  

  DM: "Right before you take your leap, you recall Delilah's song of
  the Springing Gnome. The lyrics never stuck with you before, but in
  this instant you remember 'and when the bottom in his eyeline loomed
  his toes dug in; escaped certain doom!' Safely on the other side, you
  give Delilah a thankful nod. The corner of her mouth pulls upward as
  she shoots you a majestic bow across the gap."

  
  

  
  

I would however tweak this towards the bard's personality as to not step on the player's toes, but this interaction would explain both the non-magical aspect of gaining advantage from highly inspirational performance as well as indicating to the bard that her inspiration was made use of.

Similarly;

• 
  

  Attack Roll

  
  
  

  
  

  Zaltan: "I use my inspiration."

  
  
  

  (totals 11)

  
  
  

  GM: "You recall Delilah's poem as you often do in these situations.
  The poem explained the weakpoints of goblins in a
  rhythmic, bouncing prose. Delilah notices your subtle bouncing rhythm
  instantly and clicks her tongue while shaking her head. It's a real
  shame you are fighting humans right now. Your attack misses."

  
  

  
  


• 
  

  Save

  
  
  

  
  

  GM: "The half-drow Necrolich casts a spell. Roll a wisdom save."

  
  
  

  Gallstaff: "I'm using my inspiration!"

  
  
  

  (succeeds in saving)

  
  
  

  GM: "You loudly hum the song Delilah sang just 5 minutes ago. A
  powerful song ballad about perseverance in times of strife. You feel
  the spell prodding at your mind, but the song keeps you focused. The
  Necrolich's spell has no effect."

  
  

  
  

If you aren't big on storytelling, you can simply do this once. It would explain what is happening to everyone so you can go on and streamline the experience by focusing on other things. If you cannot or do not want to then simply explain this premise to your players.