How do i do this?

[Kerilstrasz]

How can i, as Dm handle the following situation?

A npc or a player, attempts to cast a spell that reads thoughts on another player...
if the spell has a save i suppose i roll it for him/her with his mods..
but what if it succeeds? i ask the player? what if i don't want the player to know
his character thoughts are spied?

[Diarmuid]

Players have to have some ability to separate what they as the player know from what their character knows.

Unless the character can identify what spell is being cast and by whom, the only thing they would know is that they had to make a saving throw. Even if you roll if for the character, a PC always knows when they are forced to make a saving throw.

After that, unless you already know what the character would be thinking you need to ask the player for the information. Unfortunately, many players are unable to differentiate between the two and in those cases there's not much to be done about it besides trying to help them become a better gamer and develop their ability to separate "church and state" so to speak.

[SciChronic]

a player doesnt need to know that a spell was cast on them, that only occurs when they pass the saving throw, the caster also knows that the spell failed.

you just have to veil your questions as if its for another reasion you're asking. Even if the player finds it suspicious and questions you, as the DM you are under no obligation to answer

when you tell a player to make a saving throw, and then give no follow up, it its likely that the player will metagame the situation. Knowing what information to reveal to players and what to keep to yourself is what makes for a great DM. providing snacks helps too.

[nedz]

You could go for the old secret roll.

Or just cry wolf by asking for lots of Will saves when nothing is happening. If they metagame this, well they won't get very far. Eventually they will stop metagaming and you can ask for the real Will save when it actually happens.