It has to be vague in a discussion like this. You are asking for specifics that can only be known in a detailed adventure where the DM knows the layout, NPCs(with flaws, knowledge areas and personalities), etc. I also think that you are underestimating how much would be uncertain, but as you say, we broadly agree.
No, we can discuss it in concrete terms of play.
In Stonetop, for example, if a player said that the character was looking for a clue somewhere, they’d roll +Wis (2d6 plus their Wisdom score, typically between -1 and +3). On a 10+ they’d get to ask 3 questions from the Seek Insight list. On a 7-9, they’d get to ask 1. On a 6-, the GM makes a move.
Very clear procedure that can be described without the specifics of the fiction.
It seems to me that most of the trad proponents in this thread are very reluctant to talk about what actually happens at the table. Because so much of it is “the GM decides” and the more they say that, the more it makes them realize how much they’re controlling the game.
Also, I didn't say that the players would automatically succeed. I said that if the DM was acting in good faith, there would be at least a reasonable chance that the players would find out something/a clue.
You said the players could create a clue. Now you’re acknowledging that the clues come from the DM. The players can prompt the DM with questions, but it’s largely up to the DM if the question results in a clue. And the quality of the clue. And how that clue propels the PCs.
As I said… the GM has a massive amount of influence here.
No. If I have set it up so that they have neutralized the cameras or they are broken, then I have thought of it. The example given was for when the DM didn't think of it, so they wouldn't be broken or neutralized.
So the NPCs are limited by the DM in this way? So some kind of master thief would miss an obvious obstacle like cameras because the DM didn’t think of it?
Now some DMs might call for a roll, and on a roll of 1 or something they would add in a bad luck complication like the above, but would be a house rule and so isn't something I am really considering with my arguments.
Well, without resorting to house rules or ad hoc rulings, I’d think that having the NPC making some kind of skill check would make sense. Like a Stealth check.
If I was running a mystery scenario with a system like this, when the player asked about the cameras, I’d make a check for the NPC, and then narrate accordingly.
I haven't seen anything here that I would consider to be even close to overwhelming with regard to mechanics.
I was comparing the amount of GM Fiat in the mystery scenario to the amount of GM Fiat in the resolution of the Alarm spell from the OP.