D&D 5E Using booming blade on a reaction attack with sanctuary question

[Stoutstien]

They aren't mostly in the next grid. They are entirely in the next grid. If you want to visualize it as them standing at the edge of that grid that is closest to you, that's fine. In game terms, though, they are out of reach now.

And the rules say that where exactly?

 

[Maxperson]

And the rules say that where exactly?

Page 195 of the PHB.

"You can make an opportunity attack when a hostile creature that you can see moves out of your reach"

You only get it if they actually move out of your reach. Yes, you attack before they leave, but unless they move out of reach there is no AOO at all. It does not say, "attempts to move out of your reach."

It it also says, "The attack occurs right before the creature leaves your reach."

Right before it LEAVES REACH. Not, "If it never leaves reach." The "before it leaves reach" means that it is still leaving reach.

 

[Charlaquin]

I would allow it. The intent of Warcaster is to A) enable you to cast a spell as a AOO reaction, and B) do so to hurt the enemy. While it technically doesn't target the enemy directly, it's fast enough and intended to hurt and I don't see why a caster wouldn't be able to do it.

That’s fair.

 

[Plaguescarred]

The trigger can ONLY happen if the creature leaves reach. It THEN interrupts and happens before you leave, but if you never leave there was never a trigger in the first place. In effect, if you allow the creature to stop, you are allowing it to negate the AOO as it never left and never triggered that attack.

If the trigger was leaving reach, it would be out of reach to attack it. It takes place before the creature moves out, while still within 5 feet.

 

[Plaguescarred]

To pull this thread a little more, if I do this with Sentinel and he can't move any more after I hit with my polearm, does that mean he can attack me if he has only a 5 foot reach?

Yes it can, since having no speed means its still within 5 feet of you.

 

[Maxperson]

If the trigger was leaving reach, it would be out of reach to attack it. It takes place before the creature moves out, while still within 5 feet.

But it can only happen if the creature actually leaves reach. You don't have the AOO if the creature doesn't leave reach. Only the attack happens before the creature leaves reach, not the trigger. The trigger is "has left reach." No leave reach, no trigger.

 

[Charlaquin]

The trigger is "right before the creature leaves.."
Unless your AO includes a feature that forces the target to continue moving they can just stop... meaning they have spend the movement but remained I'm the same "space".
It's a result of the how the game breaks up space And movement into grids for playability.

**AOs are already silly. Moving away from a someone swinging a weapon almost always decreases the opportunities for them to hit you. Image if you gave a put two guys in a large room and gave one a stick and told the other one to not get touched by the stick. In what reality is moving towards the stick going to increase your odds of not to getting poked?

Yeah, logically AOOs should be triggered by entering the reach of a target with a longer weapon (say, reach > two-handed > versatile > any other melee weapon). But would that lead to better gameplay?

 

[Plaguescarred]

Also the Devs say Booming Blade works with War Caster


And explains their reasoning here

 

[Stoutstien]

Page 195 of the PHB.

"You can make an opportunity attack when a hostile creature that you can see moves out of your reach"

You only get it if they actually move out of your reach. Yes, you attack before they leave, but unless they move out of reach there is no AOO at all. It does not say, "attempts to move out of your reach."

It it also says, "The attack occurs right before the creature leaves your reach."

Right before it LEAVES REACH. Not, "If it never leaves reach." The "before it leaves reach" means that it is still leaving reach.

Well unless you have forced movement on that AO then they can stop or move right back where they started utilizing the same movement. The rules for AOs are about the attempt not resolution of movement. Its worded like crap yes but editing is a nightmare throughout 5e. It's the shield spell paradox all over.

 

[Plaguescarred]

But it can only happen if the creature actually leaves reach. You don't have the AOO if the creature doesn't leave reach. Only the attack happens before the creature leaves reach, not the trigger. The trigger is "has left reach." No leave reach, no trigger.

No the Opportunity Attack trigger is when it moves out but occur before it, not when it ''has left'' it. Otherwise dying from it or being otherwise unable to move after it would invalidate the trigger. The creature is still within your reach when triggering, and by the Devs, can keep moving after, or not.

Opportunity Attack: You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.