Maxperson
Morkus from Orkus
Yes it does. At a minimum, it requires the GM to establish situations which permit the player to paint a picture of his/her character that is clear and powerful; which permit the player to express his/her PC's personality, interest and agenda.
No, it doesn't. I as a player establish my character's personality, interests and agendas. Here's the thing. I don't even have to tell the DM what they are in order for me to bring them out in the game. Nothing is required on the part of the DM.
Let's say that I'm playing a dour dwarf(I know, it's a stretch ) who is interested in fine wines and with an agenda to get drunk on fine wine in every town he comes to. Without telling the DM any of that, I can seek out taverns in every town, looking for fine wine. My dour personality will become apparent in my interaction with the NPCs and other PCs. If a tavern doesn't have fine wine, I can grumpily exit and seek out a place that sells fine wine, showing that it's important to my PC that the wine he drinks be fine. And I can get drunk on it just fine. I'd even further show my agenda by keeping a few bottles of fine wine stored carefully in my pack to use just in case I come to a town that doesn't sell fine wine.
Very few interests and agendas need DM help to achieve, and I can't imagine ever needing the DM to help my play my character's personality.
What does this rogue think and feel? What is his/her agenda? Why is s/he trying to get into the castle? What might s/he sacrifice to do so?
The situation you describe does not involve advocacy of the sort that Eero Tuovinen talks about. As you present it, there is barely a character there at all!
You're making a fundamental mistake here. You're assuming that all aspects have to be present in all things to be agency. In the rogue example the player is clearly and strongly letting the DM know what the PCs is doing and why. That qualifies as full agency, even if that particular example isn't showing all aspects of what Eero talks about in that paragraph.
As for those questions, the rogue's agenda is clearly to get inside unnoticed, and he thinks there should be a secret escape route out of the castle. We don't need to know what he feels for him to be expressing his agency fully in that situation, though if the player had wished, he could have told the DM without DM help, what his PC was feeling.
Eero Tuovinen distinguishes advocacy (broadly, first person inhabitation of the PC) from authorship (broadly, thining about the PC as a protagonist in a story). This has no bearing on action resolution. Nowhere does he say that players can't declare actions which might succeed!
That's just silly. I've never even heard of a game or playstyle where players can't declare actions which might succeed.