Akkete

A good question and the correct answer seems uncertain.

As others have noted, the phrasing "a significant reduction or complete halt of military operations" is perhaps too unclear. I understand that requiring simply a "complete halt" would be unnecessarily strict. The way I see this going is that suppose a ceasefire is agreed upon, but one or both parties accuse the other of breaking the ceasefire. Does this mean the ceasefire failed? Or is these kinds of accusations expected and if military activity is noticeably reduced that's enough?

I don't think this unambiguity is a deal breaker for the question, though. As other's have suggested it might make sense to instead forecast whether a  ceasefire will be agreed upon and started, but not requiring it to hold for 30 days. This is a possibility, but has it's own downsides.

As others have said, the crowd consensus would probably be <10% pretty much from the start. I don't think that's too big of a problem, though. It's inevitable that that happens to some questions, and the 0–1% forecasts are occasionally proven overconfident, which is part of the process. I would personally forecast more like 15% initially.

However, it makes sense to try to aim for as close to 50% as possible. One way this could be achieved by loosening the resolution criteria – instead of full membership, ask about an earlier step in the process. The criteria should still be strict enough that the question is meaningful, so this probably can't change the question or the probability much. A second possibility is to extend the timeframe. However, three years is already long and it's unclear how valuable longer timeframe forecasts are (plus practical problems). 

Apart from these concerns, the question description, additional resources and resolution criteria seem good.