Off Hand Attack and Casting

[Nagog]

So, in a recent game I DMed, a player of mine cast a cantrip (Fire Bolt) as well as made an off hand attack with a short sword. He claims this is essentially two-weapon fighting without the feat (he didn't add any ability modifiers to it). Is that cleared by RAW? I allowed it but informed the party that I'd have to look into it more before making a final decision on the matter for future sessions.

[Yuki Akuma]

Nope! That isn't a thing you can do, because spells are not weapon attacks.

[Trickery]

Just about every instance of a bonus action attack in the game requires that the character has taken the Attack action, specifically. I'm not sure why WotC did this, but that's what the rules say.

There are some ways around it. The easiest one is Haste since it allows you to take the Attack action and make one weapon attack only. That technically qualifies, so you could cast your spell then make one weapon attack and one bonus action weapon attack.

[Nagog]

Nope! That isn't a thing you can do, because spells are not weapon attacks.

Good to know!


Just about every instance of a bonus action attack in the game requires that the character has taken the Attack action, specifically. I'm not sure why WotC did this, but that's what the rules say.

There are some ways around it. The easiest one is Haste since it allows you to take the Attack action and make one weapon attack only. That technically qualifies, so you could cast your spell then make one weapon attack and one bonus action weapon attack.

It may be to prevent casters using this to outshine martial classes like Monks in early game (where Monks typically shine). While Monks can add their Dex to that bonus action attack, casting a 1d10 cantrip then attacking with a 1d6 sword could quickly outpace 1d4+2/3 and 1d4+2/3, particularly if the caster decides to cast a higher level spell or use Metamagic or any other class feature.

[Millstone85]

Is the character a 7th-level eldritch knight?

If yes, the War Magic feature allows them to make one weapon attack as a bonus action after using their action to cast a cantrip. Even better, nothing says they can't add the relevant ability modifier to the damage of the weapon attack.

Otherwise, nope.

[Keravath]

No.

Most secondary weapon bonus action attacks - two weapon fighting, polearm master butt end attack, cross bow expert - require the character to take the Attack Action during their turn and not the Cast a Spell action. Fire bolt requires casting a spell. As a result, it does not trigger any of the bonus action weapon attack options.

So, in this case, No, the character can not cast firebolt and follow it up with a bonus action weapon attack. Just because a spell requires an attack roll to hit does not make it an Attack in terms of the attack action.

"TWO-WEAPON FIGHTING
When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand."

In this case, the player is trying to take BOTH the Cast a spell action to cast firebolt AND the Attack action to make a weapon attack all in the same round.

(Note that an Eldritch Knight at level 7 is specifically given the ability to do this ...

"WAR MAGIC:
Beginning at 7th level, when you use your action to cast a cantrip, you can make one weapon attack as a bonus action."

... so a level 7 Eldritch Knight CAN use a cantrip and make a bonus action weapon attack but this is a specific ability granted to that class ONLY).

[king_steve]

Is the character a 7th-level eldritch knight?

If yes, the War Magic feature allows them to make one weapon attack as a bonus action after using their action to cast a cantrip. Even better, nothing says they can't add the relevant ability modifier to the damage of the weapon attack.

Otherwise, nope.

College of Valor Bard's level 14 feature Battle Magic also allows you to make a weapon attack after casting a bard spell.


Battle Magic
At 14th level, you have mastered the art of weaving spellcasting and weapon use into a single harmonious act. When you use your action to cast a bard spell, you can make one weapon attack as a bonus action.

[Ventruenox]

Profane Soul Bloodhunters (Critical Role 3rd party character class) also have that ability similar to the EK.

A Scimitar of Speed would also allow you to make a bonus action attack if you used your action to cast a spell.