Hey, I did a forums search for Silvery Barbs but wasn’t able to find a result that answered the questions that I had.  From what I can tell, it’s been suggested that changing it from a 1st to 2nd level spell is all that would be needed to balance it out.  If that’s true, can you explain the reasoning behind that to me?  I agree that it appears unbalanced in just a theory-craft review of my own, but I couldn’t say at what level it would be the worst or if it’s just imbalanced equally from 1st to 20th all the way.  I wish there was a thread I could find that was focused, with a breakdown of all the exploits and unfair advantages it gave the party (and/or unfair disadvantages it imposed on the monsters).  Following that a series of suggestions to make it balanced (where people felt it was) and why their changes did so.  That’s what I’d love to get here, if people don’t mind.  It’s nothing that I need to specifically be worried about even this next month or probably after, but like anyone here, I enjoy thinking ahead.

I might be wrong but I think the logic behind increasing it to a 2nd level spell is simply that silvery barbs does more than you would expect for a 1st level spell but about as much as you would expect for a second level spell.

The problem with balancing is different spells scale in different ways. Burning hands is decent at 1st level and in the right circumstances could wipe out the entire enemy party but later in the game the damage is causes is irrelevent. Hold person is great at all levels against humanoids but as levels pregress they become rarer. Casting shield at level 1 is a probably sub-optimal most of the time because your spell slots are a valuable resource but at higher levels a 1st level spell slot is only a very minor resource so is worth casting nearly every time it will avoid a hit.

A player might think carefuly about casting silvery barbs at very low levels as they may be better uses for a spell slot but ut quickly becomes the best use of 1st level slots.

I think the best comparison is Heightened spell, on a straight roll forcing a reroll is effectively the same as  which flexible casting shows is between a 2nd and 3rd level spell the differences are:
Heightened spell is it doesnt use a reaction: Heightened spell is better
You need to use heightened spell before the save is rolled using the resource whether or not the the fist roll failed Silvery Barbs is better
Heightened spell can only be used on your own spells silvery barbs can be used on an allie's Silvery Barbs is better
Silvery Barbs also gives advantage to a friend next roll Silvery Barbs is better

Many monsters have advantage on saves against spells/magic and silvery barbs is not clear what to do here: "The triggering creature must reroll the d20" what happenes if they initially rolled 2 d20s do they roll them both or just one or can the spel not be used at all? Most DMs I know either rule the monster rolls again at advantage or it makes a single dice roll, the later is strictly better than heghtened spell reducing it to a single roll and the former depends on the chance of success.

Overall Silvery barbs is better than heightened spell which is considered one of the better metamagic options my view is it would still be very powerful as a 2nd level spell possibly still too powerful.

You could always try it as written. My table has been using it that way, and we’ve had no problems. I’ve actually not heard people who really use it complain, just theory-crafters.
First re-roll does not necessarily mean the result changes. I can’t tell you how many attacks we’ve forced the DM to re-roll that still hit on the second roll. We typically only use it to negate crits. The second roll isn’t a crit, but usually still hits. 

Second is the opportunity cost — every time you cast it, that one fewer use of shield, or mage armor, or feather fall or grease or thunderwave. Granted, it scales better than most 1st level spells, but that doesn’t make it OP. Really this gets back to the classic problem of the adventuring day. You’re going to have, at max, 4 level 1 slots per day. If you only have one encounter, you might see a lot of silvery barbs. But if the players know they’ll be multiple fights, or at least the chance of multiple fights, per day. They get much more judicious in using it.

So, back to my original statement, you could tell your players you’ll try it out as written, but you may need to adjust if it starts to seem too powerful.

It's just come up in my home game, and thus far it's not overly bad RAW.

If it were to become abused, I would make it like Zephyr Strike, where it would be a bonus action to cast it, concentration for a minute, and you can use your reaction during that time to force the reroll, ending the spell. That way it needs more time to set up and isn't just there at peoples beck and call.

I think the debate usually compares it to Shield and concludes that it's better. Moving it to 2nd level is more of a "it just feels right" move than a detailed calculation, because it's hard to weaken it without changing the overall feel of the spell.

Personally we've been using it (off and on as not all parties have taken it) since it came out, and it's been fine IMO. It feels good to protect your party member and buff another (or yourself), and if one part fails the other may still succeed as a consolation. Yeah, it's a bit power-creepy but seeing how we DMs have literally infinite power, PCs getting stronger has never been a worry of mine.

Quote from Xalthu >>

You could always try it as written. My table has been using it that way, and we’ve had no problems. I’ve actually not heard people who really use it complain, just theory-crafters.
First re-roll does not necessarily mean the result changes. I can’t tell you how many attacks we’ve forced the DM to re-roll that still hit on the second roll. We typically only use it to negate crits. The second roll isn’t a crit, but usually still hits. 

Second is the opportunity cost — every time you cast it, that one fewer use of shield, or mage armor, or feather fall or grease or thunderwave. Granted, it scales better than most 1st level spells, but that doesn’t make it OP. Really this gets back to the classic problem of the adventuring day. You’re going to have, at max, 4 level 1 slots per day. If you only have one encounter, you might see a lot of silvery barbs. But if the players know they’ll be multiple fights, or at least the chance of multiple fights, per day. They get much more judicious in using it.

So, back to my original statement, you could tell your players you’ll try it out as written, but you may need to adjust if it starts to seem too powerful.

Yes, perfectly this. Especially the played experience vs the theory-crafting. Once the novelty wears off in the party, it quickly becomes less often used. Heck, my table’s sorcadin ended up swapping it out for Shield because it just benefit him more with his melee focus. The bard benefit from it greatly, I’ll admit, but turning away one attack per round is not a big deal at all and it competed with his other reactions. Put a single creature with multi attack on that SB caster and they will regret not having taken Shield instead. Guaranteed. Thank you for also pointing out the number of encounters per day because yes, this has an influence on its use too. If a DM only does one encounter per day and this becomes something of an expectation, you will see your players spamming everything they have and SB will have a large focus. From my perspective, I think being predictable with single encounter days is a bit lazy as a DM and if that is all you want to do as a DM, then it should be acceptable that players use their best tools at every tier every time. My players have no idea how many encounters they get in a day and I believe that is how it should be. 

SB is situationally better than Shield, generally speaking. It does do more than L1 spells would be expected, but I also feel that L2 slots are too costly at the beginning and then later on become largely indistinguishable from L1 slots anyway. It occupies a strange limbo where a L1 slot feels too cheap (because it does more than other L1 spells do, but anything more than a L1 slot is too costly.

It's not game-breaking as a L1 slot, it's just that awkward potency-to-cost ratio that makes it seem to stand out.

It’s fine at level 1. It’s useful but… consumes a reaction and a slot. Also, if the party have it, the monsters have it.

My players had been using it at our table a lot; it became a magical staple, but it doesn’t feel overpowered to me. We’ve had lots of times where it hasn’t changed the result. Also, occasions when players have blown a reaction on an offensive use of SB that should’ve been saved, and then suffered. It’s a useful tool but kind of “meh” now that the novelty has worn off. 

I think it adds some “counterspell” style flavor to the low-level magic system, which is kind of fun.

It’s a great spell, but not worth the hassle of house-ruling imo.

The spell actually isn't all that bad except that it scales without an increase in cost when using it to force rerolls on saving throws.

Think about it like this:  if you cast disintegrate on a target and they pass the save, you'd typically need to wait until your next turn to try again, spending another 6th level spell slot (which you only get at level 19), and you'd have to spend another action.  Silvery barbs instead let's you force another roll for a first level slot and a reaction.  If you really like this spell, then I'd say wait until you're DM starts using it.  To make it worse, high level wizards can cast this spell at will, literally forcing a reroll on almost every saving throw that doesn't go the wizards way.

I think there are a few good options:

1.  Remove the spell saving throw part of the spell.  This is problematic part.  Forcing a reroll on a critical hit against your wizard is still a really good use for a first level spell slot.

2.  Have the saving throw part scale with higher level slots and have it only work with spell saves, not other saving throws.  For example: forcing a reroll on banishment would require casting silvery barbs at a 4th level slot.

3.  Just remove the spell.

Quote from scatterbraind >>

Yeah, it's a bit power-creepy but seeing how we DMs have literally infinite power, PCs getting stronger has never been a worry of mine.

 Yeah, but the other players at the table aren't necessarily keeping up, is the problem. I guess the DM can always homebrew stuff to make them just a little bit stronger or something, but eh.

I do think it's interesting that everyone I've heard say they've used it, says it's fine. I've heard enough voices on this now to think it's not just a fluke.

One thing I don’t like is the idea of having to increase the threat of encounters to account for a single spell.  If that’s the case here, it has no place as is in anyone’s games.  There’s an idea of relative balance in 5e, which is why some changes get more harshly scrutinized than others.

Quote from Appellion >>

One thing I don’t like is the idea of having to increase the threat of encounters to account for a single spell.  If that’s the case here, it has no place as is in anyone’s games.  There’s an idea of relative balance in 5e, which is why some changes get more harshly scrutinized than others.

Speaking from experience as DMing for Silvery Barbs, you really do not need to increase the threat of encounters to account for it.  Personally, I find the effect good, but ultimately not outcome determinative of fights--so much so that I never take it into account during encounter design, and I have never once felt "oh, darn it, I should have considered Silvery Barbs!"  It is a good spell--and a solid use of both a level one spell slot and a reaction (losing a reaction is a pretty significant cost)--but it still only effects two rolls at a time.  

To be perfectly frank, if Silvery Barbs is causing a DM problems, it is probably not the spell that is the problem--it is probably the DM designing an encounter that would have been too easy with or without the spell (and quite possibly a problem with the abject mediocrity which is the CR system). 

Quote from Appellion >>

Hey, I did a forums search for Silvery Barbs but wasn’t able to find a result that answered the questions that I had.  From what I can tell, it’s been suggested that changing it from a 1st to 2nd level spell is all that would be needed to balance it out.  If that’s true, can you explain the reasoning behind that to me?  I agree that it appears unbalanced in just a theory-craft review of my own, but I couldn’t say at what level it would be the worst or if it’s just imbalanced equally from 1st to 20th all the way.  I wish there was a thread I could find that was focused, with a breakdown of all the exploits and unfair advantages it gave the party (and/or unfair disadvantages it imposed on the monsters).  Following that a series of suggestions to make it balanced (where people felt it was) and why their changes did so.  That’s what I’d love to get here, if people don’t mind.  It’s nothing that I need to specifically be worried about even this next month or probably after, but like anyone here, I enjoy thinking ahead.

As one of the people who proposed this, I can tell you some of the reasons why I suggested that Silvery should become a 2nd level spell. In my experience, Silvery Barbs has completely outperformed its spell level and messed up the game's challenges.

The reasoning behind making it a second level spell is simple: This is an easy tweak that requires next to no work to implement, and it makes it significantly harder to just spam the spell. Not to mention the fact that casters will no longer get access it it the second they start playing D&D at level 1.

Other interesting ways to balance Silvery include preventing it from being used against natural 20s, barring it from giving advantage to an ally unless it is casted with a higher level spell slot, or just banning it altogether. You're the Dungeon Master at your table after all, and if you worry about something ruining the game for you or some of your players, then you certainly aren't required to allow it or let it do so.

I'm not going to bother debating here whether or not Silvery is completely broken or just really good, because a ton of people have had it used in their games and it was fun, while for a number of other groups... Not so much. Ultimately, I think you have to make your own conclusion about how Barbs might affect your table and the challenges you set for the party, as well as whether or not you want to allow it unmodified. You could always have a group discussion with your players if you want to see what they think about the spell and what changes to it might upset or confuse them.

What about if it only affected attack rolls or skill checks, but could be upcast to a 2nd level slot to affect saving throws as well?

I think that Silvery Barbs stands out in this way because, in many games, once players have it they cast it constantly. It doesn't impact the game as much as many people seem to think it does, but it feels like it's having more impact than other, more technically useful 1st level spells because those spells will come up... maybe once a session? Whereas Silvery Barbs can get cast in combat to defend from powerful attacks... to force disadvantage on a Saving throw... to counter a push or shove. Even outside of combat you can still use it to hamper opponents, and then on top of that you can give someone else advantage... not just on attacks, but skill checks and saving throws. If you've got the spell slots to spare, Silvery Barbs could be cast more times in a single battle than Healing Word gets cast in a full month of games. Not to mention that some DMs even allow multiple casters to stack Silvery Barbs' on a single saving throw.

Silvery Barbs is kind of like one of those songs that you hear way too often on the radio. Maybe a little annoying, but you might even enjoy it under the right conditions. But the fact that you Just. Keep. Hearing. It. makes a mildly frustrating song into the bane of your existence.