There is one thing that I'm a little bit unclear on in the Challenges phase. Is declaring a challenge a player action or is there a player action window at the beginning of the challenges phase before First Player actually has a chance to declare his/her first challenge? I assume that it's a player action that, like marshalling a card with a gold cost, can only be taken by the active player, in which case declaring a challenge would be the first player action of the phase. However, in my meta (as small as it currently is), we usually allow a round of non-challenge player actions before the first player gets to declare a challenge, and I haven't contested this as I wasn't completely sure. Thanks in advance for the answer.

I can see where you're coming from, as the marshalling phase player actions are a bit odd and alternate despite only one player being "Active" and able to marshall. However, declaring a challenge is a framework action, not a player action, and it is a framework action specifically restricted to the "active player". Before any player declares a challenge, there's a player action window.

All of this information is available in greater detail on p.21 of the FAQ (Timing Charts).

Yep.

Declaring a challenge is a framework event, like revealing plots in the plot phase, drawing cards in the draw phase, settling claim, or returning gold to the gold pool during taxation. So, like all framework events, it doesn't happen until the framework action window opens - after player actions are taken.

As a framework action, it is a little unusual in that there is a certain degree of player choice involved (do you initiate the challenge or not) as opposed to simply happening. However, it is not a player action; it is a game mechanic that happens regardless of what cards are on the table. (eg, even if he has no characters, the active player still has to say he has no challenges.)

Okay, cool. Thanks for the replies (and, yes, I have read through the FAQ pretty thoroughly - more than once along with all of the errata'd versions, as I like to have a thorough understanding of the rules) I just wasn't sure if the framework begun with the player action of initiating a challenge or if the framework itself was the challenge initiation, so I asked for clarification.