Green Flame Blade + Shield Master?

[KOLE]

I’m currently working on a Bard build for an upcoming campaign, and I’m a big fan of the Shield Master feat. I am nearly positive- by RAW- using a SCAG cantrips such as Booming Blade or Green Flame Blade would not count as making an attack and thus not qualify me for Shield Master’s bonus attack. If I’m wrong in that, please correct me.

However, I’m pretty sure my DM would let me get away with it, so I’m doing my due diligence here. Do you think this would be unbalanced? Bards are full casters after all, I’m sure there’s a lot of spells I could cast that would be more significant than my meager melee damage +d8 and knocking someone prone, not to mention to do this puts me in the middle of the fray and to get out of dodge would involve taking a AoO (albeit with disadvantage).

I like the idea because we’ll have multiple casters/squishies (two wizards and a warlock) in the party putting more of an emphasis on my support/melee role alongside the Barb and Pally. I feel like knocking baddies prone helps my support role, and I’ll be carrying a shield anyway. (I’m a BIG ac glutton, most of my characters end up with shields.)

For those wondering, I’ll be taking Valor Bard and picking up SM at level 4.

[thrdeye]

I’m currently working on a Bard build for an upcoming campaign, and I’m a big fan of the Shield Master feat. I am nearly positive- by RAW- using a SCAG cantrips such as Booming Blade or Green Flame Blade would not count as making an attack and thus not qualify me for Shield Master’s bonus attack. If I’m wrong in that, please correct me.

Using a SCAG cantrip counts as making an attack, but Shield Master's bonus attack requires you to take the Attack action specifically. When you use the cantrip, you are taking the Cast a Spell action. However, if your DM will let you get away with it, go for it.

I don't think it will be too unbalanced unless you throw in a Hexblade dip or something like that.

[KOLE]

I don't think it will be too unbalanced unless you throw in a Hexblade dip or something like that.

For this campaign specifically, there won’t be any multiclassing shenanigans, so that takes some of the potential for abuse out of the picture.

[Naanomi]

I don’t see any obvious problems. I once wanted to do a strength-Swashbuckler/rogue that combined shield mastery and Booming Blade; but the GM (accurately) veto’ed it on rules technicalities.