List the engines you have running: which world and BRANCH each is bound to, whether it is a browser tab, a native engine or a player, and whether another conversation is already driving it. Call this when a tool tells you the target is ambiguous, or before session.connect, to see what there is to choose from. A player (drivable: false) is someone playing the world in the runtime profile: it takes no edits and keeps nothing when it exits, so it is listed for you to see and is never driven or bound.