Casting a Spell
A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. You can't cast another spell during the same turn, except for a cantrip with a casting time of 1 action.
This is the current rule for casting any spells (cantrip or otherwise) on your turn as a Bonus Action.
I would like to incorporate an change of this rule in my games. However, I'm not 100% clear on the balance impact it would have on the game as a whole. The goal of the rule change is to have a similar rule which functions cleanly across common edge cases (seems oxymoronic but isn't) listed below.
Casting a Spell Rule Change
A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. If you cast two or more spells in a turn and one of them was a Bonus Action, one of the other spells must be a cantrip.
The wording could use adjustment to fall in line with rule parlance.
Is this rule change balanced? In terms of balance, this should not tip the level of power any class has significantly. It shouldn't have massive effects on the average DPR of a class, it shouldn't reduce the value of class options that involve spellcasting (there shouldn't be any feature that this rule change makes worse), and there shouldn't be a heavy opportunity cost for not making use of this rule in this way.
If not, what changes would need to be made to keep with the spirit of the changes but remain balanced? The spirit of these changes are to increase the flow of gameplay, not to tip-toe around an unnecessarily restrictive rule.
Let's see how this addresses each problem one-by-one.
There are two cantrips currently with the action speed of Bonus Action: Shillelagh and Magic Stone. Casting either of these spells as a Bonus Action immediately limits the spellcasting options for the turns Action to cantrips.
Now, for these two cantrips, it's somewhat clear that the intention behind them is to use them on a turn that you are going to hit someone with a Shillelagh or throw a Magic Stone. These are not the true victims of this rule, as I see it.
Consider any instance of a Bonus Action cantrip below to be one that has been quickened, to avoid confusion with the resource expenses in the general cases.
Problem 1 before Rule Change
A Sorcerer gets access to Quicken Spell, in which they can make any spell in their arsenal a Bonus Action speed spell, if it was originally Action speed. There are two ways in which a Sorcerer can use the Quicken Spell Metamagic.
- They can quicken a spell of level 1 or higher.
- They can quicken a cantrip.
Now, the problem comes after this point: Regardless of which choice they make, the Sorcerer can now only cast a cantrip as their Action. Based on the decision above, the Sorcerer can either cast Two Cantrips, or a cantrip and a proper spell (level 1 or higher).
I'll be calling the case in which the Sorcerer can cast a cantrip and a proper spell the optimal case because it is the one with the least restrictions.
Consider the hypothetical situation, let's say that the Sorcerer were to quicken the cantrip as their first activity during the turn. Then, they were to cast a proper spell. In what way does this impact balance? The Sorcerer, would have performed the same actions and spent the same resources as the optimal case. Sure, we can say that the Sorcerer can just spend their resources to quicken the other spell instead. Then, there's no problem. However, we run into issues once we expand the problem space.
Problem 1 after Rule Change
If the Sorcerer casts either a cantrip or a proper spell as a Bonus Action, they can cast the other as their Action. Why?
- The Sorcerer quickens a proper spell. They try to case a second spell: cantrip. Since they are casting two spells in one turn and one of them is a cantrip, it's allowed.
- The Sorcerer quickens a cantrip. They try to case a second spell: proper spell. Since they are casting two spells in one turn and one of them is a cantrip, it's allowed.
- The Sorcerer quickens a cantrip. They try to case a second spell: cantrip. Since they are casting two spells in one turn and one of them is a cantrip, it's allowed.
The same resources are being spent in the first two cases, allowing a Sorcerer to cast a proper spell and a cantrip with Quicken Metamagic on either one of them. It also preserves the option to cast two cantrips.
This affects timing and liberates the Sorcerer to make decisions about their Action based on the results of their Bonus Action, and vice versa. Nothing is taken away from the Sorcerer with this rule change.
Problem 2 before Rule Change
Consider now a Sorcerer with Action Surge under the same constraints. They can cast a either two cantrips, or a cantrip and a proper spell. If the Sorcerer then uses Action Surge from cross-classing Fighter, they are given another Action fro the turn. Depending on the previous activity during the turn, the Sorcerer's options for this additional action are limited. Either:
- The Sorcerer can cast a cantrip with that action.
- The Sorcerer can cast a proper spell with that action.
- The Sorcerer can do any non-spell action.
Let's consider only the casting actions going forward. With this in mind, let's consider the cases available to us and look at the cases.
- The Sorcerer can cast three cantrips.
- Bonus Action: Quickened Cantrip
- Action: Cantrip
- Action: Cantrip
- The Sorcerer can cast one proper spell and two cantrips.
- Bonus Action: Quickened Proper Spell
- Action: Cantrip
- Action: Cantrip
- The Sorcerer can cast two proper spells.
- Bonus Action: not a spell
- Action: Proper Spell
- Action: Proper Spell
This last case, in which the sorcerer can cast two proper spells is the outlier here.
If the argument is that the bonus action casting rule is to prevent a player from casting two proper spells in one turn, then rules as written, it has failed to ensure that. There is a fairly easy way to be able to cast two proper spells in one turn once per short rest as detailed in the third case.
It is incredibly arbitrary that the second case, the one in which we can cast a proper spell and two cantrips, requires us to quicken the proper spell to proceed. There is not a clear apparent benefit gained to having cast the cantrip first to warrant such a restriction. There is a way to cast two cantrips and a spell, so what does it matter if the cantrip is the Bonus Action?
Note: Case 2 is analogous to the case in which an Eldritch Knight casts a proper spell which is normally a Bonus Action, such as Expeditious Retreat. Case 3 is analogous to an Eldritch Knight casting two proper spells with Action Surge. The example build is not cherry-picked to prove any points, it simply makes the conversation easier than outlining all possible ways of achieving these types of spell castings.
Problem 2 after Rule Change
In the case of additional actions, things are far better in favor of the Sorcerer. Consider Cases 2 and 3 in Problem 2, with this change, the Sorcerer is able to cast three spells in one turn, and two of them can be proper spells.
The Sorcerer was already able to cast three spells in one turn, but at most one of them could be a proper spell. However, they were also able to cast two proper spells. Since it was always within their power to cast two cantrips and a proper spell any time they could cast two proper spells, I'm going to consider only one of these to be the optimal case: casting two proper spells.
The optimal case for Sorcerer with Action Surge improves under the rule change by gaining the option to spend 2 Spell Points to cast an additional cantrip. Again, nothing is taken away from the Sorcerer.
Problem 3 before Rule Change
Consider now a Sorcerer that has prepared Counterspell and one other proper spell for the day and knows a cantrip.
Let's say that the Sorcerer can cast a spell as a quickened proper spell and then an enemy spellcaster casts Counterspell against that quickened proper spell.
The rule indicates that because the Sorcerer is casting a proper spell as a Bonus Action, the Sorcerer cannot cast Counterspell on their turn to Counter the Counterspell being levied against them. The Sorcerer must then, because they are using their proper spell as a Bonus Action, give up on that spell and can only cast a cantrip in the remainder of their turn.
If the Sorcerer were casting the spell as an Action, they would be able to cast the proper spell and Counterspell the Counterspell being levied against them.
The difference here is that in the first case, the Sorcerer would be able to cast a cantrip with their remaining action, whether or not their first spell was countered. In the second case, the Sorcerer would not be able to cast the additional cantrip as a quickened spell because they have cast a proper spell in the turn.
Effectively, the rule's impact on this situation is that using a quickened Spell makes a spellcaster more vulnerable to Counterspell than they normally would be, with the only compensation being that they can cast a cantrip instead.
In the general case of the Sorcerer, this seems like cherry picking. However, it has major implications for a class like the Lore Bard with Healing Word, Cure Wounds, and Counterspell (Magical Secrets).
The Bard may want, at some point, to heal someone with Healing Word as part of their turn, to raise a fallen ally before they fail their third death save. However, because Healing Word is a Bonus Action spell, they are unable to counter an attempt at Counterspelling them for the same reasons outlined above. However, if they spent their exact same resources on Cure Wounds, they would be able to Counter a Counterspell.
The difference is minimal here other than the ability to Counterspell, and seems arbitrary. By casting a longer range and weaker spell, the Bard has given up the ability to cast Counterspell and protect it.
Problem 3 after Rule Change
In the case of using Counterspell on your turn, the rule change allows for the following scenarios.
- The Sorcerer casts a cantrip as an Action. The Sorcerer casts a proper spell as a Bonus Action. The Sorcerer is available to cast Counterspell with their reaction on their turn.
- The Sorcerer casts a cantrip as an Bonus Action. The Sorcerer casts a proper spell as a Action. The Sorcerer is available to cast Counterspell with their reaction on their turn to defend the proper spell.
- The Sorcerer casts a proper spell as an Action. The Sorcerer is available to cast Counterspell to defend the proper spell. The Sorcerer casts a cantrip as a Bonus Action.
- The Sorcerer casts a proper spell as a Bonus Action. The Sorcerer is not available to cast Counterspell to defend the proper spell. The Sorcerer casts a cantrip as an Action.
The last case seem off. If the Sorcerer did cast Counterspell and cast the cantrip afterwards, the turn would be in compliance with the rule. However, since there is no guarantee that the Sorcerer would be able to cast the cantrip before the end of their turn (ex. could die to their own Fireball they just cast), they can't cast Counterspell or they risk breaking the rule.
I can't figure out how to resolve the last case without making the rule change more complex and introducing edge cases into the writing. Ideally, that last case should allow the Sorcerer to cast Counterspell, in my opinion.
However, the Sorcerer has avenues now for casting both a cantrip and a proper spell and being able to defend either with a Counterspell. This does not take anything away from the Sorcerer.
Again, note that a Sorcerer was used as an example for much of this question, but the problems are more general and affect other classes as well. It was simply done for simplicity.