So there are two approaches to framing, if the player has as a goal for his/her PC "I will find an item to help confront my balrog-possessed brother before leaving town":
(1) The GM tells the player "You're in a bazaar, with a peddler offering an angel feather for sale. What do you do?"
(2) The GM tells the player "You're in the town. What do you do?
The content in (1) itself reflects player agency - it is the GM directly engaging the player's statement of dramatic need. The content in (2) does not.
The content in (1) reflects less player agency than the content in (2) does. In and of themselves they are equal statements - in each case the player is looking for an item for a specific reason but has (I must assume) no idea what that item may be or even if it can be found in this town, and in eac case the DM is trying to jumpstart that process. Both speak to the agency exercised by the player in setting that goal, to find an item to help his brother out. But (1) railroads the player straight to the (or a) possible solution, while (2) gives the player the agency of choice in how to approach the search for the item.
(1) certainly saves a lot of time if you-as-DM already know the feather is the key...but in theory you don't already know that, and in fact the feather turned out to be a false lead.
As a player, I know my answer to (1) would be "How did I get here, who is with me, why am I here, and what else is around me?" where for (2) it would be some version of "I look for information via rumours, sages, and bardic tales; and ask my erstwhile companions to please do likewise on my behalf".