Level 6 Bladesinger Wizards have a unique Extra Attack feature:

You can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.

I read "one of those" to mean "one of the two attacks that you can make with Extra Attack". But I have seen other people make a different reading: since "those" is plural, this means the Bladesinger needs to make 2 attacks (or more) in total to use this half of the feature.

This reading sounds fine to me, but I'm unsure how it would resolve some fairly common situations:

  1. The Bladesinger attacks a goblin, and swaps their first attack for Booming Blade. They kill the goblin in 1 hit. There are no other enemies around. Since the Bladesinger made only 1 attack, is that legal?
  2. The Bladesinger decides to only attack once, they tell the DM: "I know I am allowed to attack twice, but I just want to do 1 attack". Can they swap that one attack out for a cantrip?
  3. The Bladesinger doesn't declare their intentions, and asks to use a cantrip on their first attack. The DM doesn't know if they are going to make a second attack at all, is that allowed?

There may be other situations like this which are difficult to resolve. What's the deal here? Can the Bladesinger even use a cantrip on their first attack? Which reading is correct, and if the later is correct how do we resolve these situations?


2 Answers 2


It makes no difference

Let's look at two situations:

You use the Attack action

You choose to use one of your attacks to cast a cantrip, as you are allowed to. Now you can choose to make a second attack, but nobody forces you to do that:

You can attack twice, instead of once, whenever you take the Attack action on your turn.

You take the "Cast a Spell" action

You cast e.g. Booming Blade once, then do nothing else in terms of attacking.


You casted a cantrip once, then did nothing else to attack, leading to exactly the same result. Since Extra Attack doesn't specify you need to attack with a normal attack first, you are free to make one attack with a cantrip and then not use the remaining attack action.

  • 2
    \$\begingroup\$ When I first read the question I agreed with you that using the Cast a Spell action to cast a cantrip would be equivalent to using the Bladesinger's Extra Attack but only attacking once, but technically there are bonus action cantrips that you wouldn't normally be able to use your action for, but that I think could be cast as (part of) an Attack action as a multiclassed Bladesinger. I'm not sure how this could possibly be useful, but it did come to mind. (Magic Stone and Shillelagh are the only two I'm aware of.) \$\endgroup\$ Commented Nov 19, 2021 at 9:56
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    \$\begingroup\$ @KernelPanic A quick DNDBeyond search shows those are indeed the only two bonus action cantrips. I also assume that the extra attack feature does not allow you to change the casting time of a spell cast this way, since it only does what it says, nothing else. \$\endgroup\$
    – Tobias F.
    Commented Nov 19, 2021 at 10:13
  • 2
    \$\begingroup\$ @KernelPanic Turns out that question has been asked on the site already \$\endgroup\$ Commented Nov 19, 2021 at 13:10
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    \$\begingroup\$ It would make a difference if they were subjected to the Haste spell. If they need both attacks available to replace one with a cantrip, then they can't use that extra action to do so, but if they can use it while only making one attack, then they can use that hasted action and replace the attack with a cantrip (assuming the cantrip has a weapon attack involved, to fit with Haste's prerequisites). \$\endgroup\$
    – RallozarX
    Commented Nov 20, 2021 at 0:24
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    \$\begingroup\$ @TobiasF. Yes, Haste and Slow both limit you to 1 attack (an Attack limited to 1 attack in Haste, and 1 attack per turn in Slow). While slow does let you use an action to cast a spell (although there may be other nuance I haven't thought about), Haste doesn't. \$\endgroup\$
    – user73918
    Commented Nov 23, 2021 at 8:13

You are not forced to make the two attacks

I would interpret the rules the same way as you. While based on the way the feature is written, both readings seem possible, the one when you are forced to actually make two attacks in order to cast a cantrip seems unnecessarily restrictive.

If anyone would insist on the "hardline interpretation", I suppose they could circumvent the mentioned problems like this:

  1. A character needs to declare their intentions fully before taking the Attack action.
  2. Only the state of the world before initiating the action matters. If there is no valid target after using the cantrip, nothing happens; you don't roll back time.

To me, it seems that approaching combats like this would only slow down play and add additional sequencing roadblocks and unnecessarily complicate the turns.

As for the rules themselves, I don't think that the wording is precise enough to say that either of the interpretations is correct. Which would eventually leave things in the DM's hands, as they usually are.

  • 1
    \$\begingroup\$ Notably about point 1.: 5e allows moving between attacks. It would make playing very awkward, if one had to declare their actions (or just attacks) before moving, because a lot of stuff can happen while moving (traps, bonus action teleport, opportunity attacks, readied actions including spells, Sentinel feat effect....). While narratively everything happens at the same, mechnically it does not in 5e, and narration needs to adapt to describe concurrently the sequential actions during a round. \$\endgroup\$ Commented Nov 20, 2021 at 6:13

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