iserith
Magic Wordsmith
I believe secrets rolls do sometimes make the game better, and I use them.
Example: PC is using insight against an NPC who is lying to them. PC is highly skilled, say +9, and rolls a 17 (26) in the open. DM rolls behind the screen and gets a 18 and the NPC is secretly a master spy, adds +9 (27). Result is "you cant read him".
Just by seeing his own roll of 17, and knowing he is good at insight, and getting the "cant read him" result, this player has now been tipped off that there is something special about this NPC.
If the DM made the roll for the PC however, this situation is avoided. The PC just gets the "cant read him" result without knowing his roll was 17.
Is there a better way to avoid this kind of tip off whilst still letting the player roll in the open?
There's a lot of missing context that had led up to the player being able to declare a goal and approach and the DM finding it to be uncertain. So I think it's fair to say that at the point the player describes wanting to discern the NPC's truthfulness, both the player and the character have reason to believe something is up. (My point being, you don't just get to roll every time you declare you're trying to discern truthfulness. At my table, you just fail outright without time spent in the interaction plus evidence of some kind, however tenuous.)
Further, the character is quite skilled in Insight given that bonus, so it's also reasonable in my view to narrate the character as doing a very good job of observing the NPC's body language and mannerisms and coming up with nothing, which reveals to the character that this guy is either telling the truth as he understands it or is just as good at telling lies as the PC is at picking up on them. That is what a character this skilled might also think which means the player's thoughts and character's thoughts are reasonably in line.
The long and short of it is, if you're concerned with that kind of "metagaming," you want to narrate in a way that lines up the player's perception of the situation with the character's, given the context of the scene. In this case, the character can't discern a lie, but knows something is up. This is just "progress combined with a setback," essentially, which is often my go-to tool in these kinds of situations.