Does the opportunity attack granted by War Caster have disadvantage? [duplicate]

Question

I am going to start a new 5e campaign, nobody having played it before.

I was asked whether it would be sensible to take the War Caster feat and stumbled over the problem of whether its opportunity attack is made with disadvantage.

Since, as far as I am aware, a creature trying to leave the reach of a PC is the only way to trigger an opportunity attack, any magic opportunity attack that requires an attack roll would be while the target creature is still in 5ft and conscious, and therefore be made at a disadvantage.

Is my reading of the rules correct? If not, what did I miss?

Answer 1

Only if the spell attack is a ranged spell attack

Ranged attacks, whether from a spell or weapon, have disadvantage at 5 feet. Melee attacks and spells that cause a saving throw do not. A melee spell attack granted by a spell such as shocking grasp would not have disadvantage if used as an opportunity attack granted by War Caster.

Answer 2

Varies by the Spell Type, and your reach

First, let's take a look at the text of War Caster:

When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature. -PHB p170

Then note the text on casting spells with disadvantage.

Most spells that require attack rolls involve ranged attacks. Remember that you have disadvantage on a ranged attack roll if you are within 5 feet of a hostile creature that can see you and that isn’t incapacitated (see chapter 9).-PHB p204 (italics added)

Finally, let's consider the rules on opportunity attacks:

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. -PHB p195 (italics added)

Note that it has been clarified by Jeremy Crawford that:

[T]he spell you cast in place of an opportunity attack has the same timing as an opportunity attack.

This tells us two things in order to cause disadvantage on your spell:

• The spell must require a ranged attack roll

• The enemy must trigger an opportunity attack while within 5 feet of you.

That means there are three ways to avoid casting a spell with disadvantage.

1. Cast a spell with no attack roll, like Sacred Flame or Disintegrate.
2. Cast a spell with a melee attack roll, like Shocking Grasp (as mentioned in THiebert's reply).
3. Have a reach of more than 5 feet, such as by using a pike. Since the target will trigger an opportunity attack when they are further than 5 feet away from you, you could then cast any spell you wanted.

You could also avoid this situation altogether by taking the Crossbow Expert feat. Most of the features of that feat don't help casters very much, but it allows you to make ranged attacks without disadvantage if an enemy is within 5 feet of you, including spell attacks (according to http://dnd.wizards.com/articles/features/sageadvice_feats).