I don't see it.I just want to be sure that you realize there is a difference between having character's actions matter and "altering the game reality." Player's want their choices to matter (have agency), that doesn't mean they want the game reality to change because of those choices.
Most of the "storytelling agency games" have a mechanic that alters game reality. Like the "I know a guy one". The character encounters a a locked door, and the player just says "Oh I know a guy that made me a skeleton key". And POP reality is altered, the character "suddenly" just "has" the key and opens the door.
Or the games with the things like: the character is walking down a road, and the player just says "gosh I sure wish my best NPC pal would be coming down this road right now in a wagon to give my character a ride". And POP reality is altered, and the NPC "just happens" to "amazingly" be coming down the road in a wagon.
I think you know.I don't know exactly what "game reality" means.
Taking actions with in the game reality, do not change game reality. A character killing an orc is part of the reality. Changing reality is simply doing an action in the game not through a character. It's what GMs do.
Not altering game reality: Character walks up to the edge of a large river bank, player asks the DM what they see.
Altering game reality: Character walks up to the edge of a large river bank, and player says "oh my characters Brother Boatman is comming down the river in his boat at this exact second and picks up my character." Dm just nods yes.
I put some examples above.I don't know what people mean. That's why I said as much.
I don't know what all these games are that let players make changes to the fiction other than by declaring actions for their PCs. I only seem to see them mentioned by people who don't play them.
No they don't. A Traditional game is: GM makes up and controls everything and player plays their character. That's it.'Changing reality' implies that something defined was contradicted. What's generally being discussed is filling in things that haven't been defined - 'creating reality'. Players in traditional games do this all the time.
Very specifically a traditional game is a player asking the GM what their character sees, so they can have their character react to it with in the game.
It is. Sadly what happens is some gamers play some of the Other Games and think they are beyond great. But then they go back to playing D&D, and bring the ideas with them. So even though 5E D&D does not have a "I know a guy" rule, players will whine or demand it be added to have "player agency".But bloodtide is talking about D&D, not other games. I have not heard of people doing this in D&D games and blood implies it is commonplace.