Mental Barrier

[Hannibal78]

The Mental Barrier is lvl 2 spell, what you can use like your reaction, when you are forced to make an Intelligence, a Wisdom, or a Charisma saving throw.

Now, the question is: there are hardly noticeable spells. If you cannot see, hear, you cannot use your reaction to use Counterspell on it, as i could read.

What is the situation with the Mental Barrier? It's the same? Or, cuz there isn't in the text, by RAW, if a spellcaster knows or the spell is prepared, the DM always should inform the player if a spell requires saveing throw, cuz mb the player want to use it?

[sithlordnergal]

The Mental Barrier is lvl 2 spell, what you can use like your reaction, when you are forced to make an Intelligence, a Wisdom, or a Charisma saving throw.

Now, the question is: there are hardly noticeable spells. If you cannot see, hear, you cannot use your reaction to use Counterspell on it, as i could read.

What is the situation with the Mental Barrier? It's the same? Or, cuz there isn't in the text, by RAW, if a spellcaster knows or the spell is prepared, the DM always should inform the player if a spell requires saveing throw, cuz mb the player want to use it?

Its actually different from Counterspell. Mental Barrier's Casting Time states "1 reaction, which you take when you are forced to make an Intelligence, a Wisdom, or a Charisma saving throw".

Where as Counterspell states "1 reaction, which you take when you see a creature within 60 feet of you casting a spell".

Mental Barrier is more like Shield or Absorb Elements then it is Counterspell. Counterspell goes off when you see someone else doing something, Mental Barrier, Shield, and Absorb Elements go off when something happens to you. Heck, with Shield you can use it if you're attacked by a hidden creature, provided you aren't Surprised.

I don't remember if RAW exactly says anything on the topic, but as a general rule the DM should always inform the player if they're making a saving throw and what kind of save they're making. Otherwise it would be on the DM to remember things like an Elf's advantage against Charm effects, spells like Foresight, Hero's Feast, ect. which also give you advantage on Mental Saves, class abilities that aid in saves, ect..