As far as I can tell, this is the only point you and I really disagree on. I think because for the types of players I described, it would be seen as diminishing agency. I would agree that for some people it will increase overall agency. But this is, to me a pretty important way it isn't as simple as agency increasing across the board the more places you give players control. And the way I was using agency, I meant it pretty much as freedom to play my character in the world. If I tell the GM he or she is taking away my agency, I don't mean that they are failing to give me narrative control of the setting, I mean they are doing something like railroading or not really considering the choices the players are making in the game and where those choices ought to lead to.
Sure, I would agree. A railroad is a way that agency is taken away. But there are also people who are perfectly happy to play in a railroad game. And even those players may have some agency; they may not be able to deviate from the path, but they may be able to decide something like using stealth or diplomacy to bypass a monster, rather than just fighting it.
It’s a spectrum.
So then what are the upper limits of that spectrum? What would you say is an example of a high agency game?
I don't agree with this, because...
I don't agree with this. I think... I'm pretty sure I just don't see agency in the same way than you do. I try to explain. If you get to define both the conditions, and the reaction to those conditions; define both the question and the answer; then, yes, in a sense you have more freedom. But I wouldn't say that you necessarily have more agency. Agency, at least in the context of a game, is making meaningful choices, and I feel that it is the limits that make the choices meaningful. You respond to something external, and this makes your responses meaningful. If anything that limits the player's freedom is seen as reduction of agency, then ultimate agency would be achieved by removing the rules, the dice and the other players as all of those limit the player's freedom. And I'm not sure that this would be a reasonable or useful definition of agency.
This is a relevant point. And I think that the kind of extreme authorship by players that you’re talking about shifts the game into (?) or toward (?) something else. Something like Microscope or Fiasco, maybe.
I’m not saying that there can’t be or shouldn’t be restrictions on player authority. Just that there are degrees, right?
Just like with the character level agency you guys are talking about is not absolute. There are times when stuff your PC does is not actually up to you, or where the options available to you are limited.
This is still true with more narrative based elements.
No one’s advocating for players to be able to craft anything they want whenever they want.
So let’s say your GM asks you if your group would rather have him run an adventure path, or a more sandbox style game. There will be constraints on agency in each game, likely of different kinds, but still constraints.
If agency is the ability of the player to determine the course of the fiction, one of those will likely offer more agency than the other.
Then if you added the ability for players to determine some of the contents of the fiction beyond just what their characters do and say, that’s also more agency.