a question came up during my last game and I could not resolve it with the rules reference. In the reference under AOO it says:

An attack of opportunity is made immediately after all costs of initiating the action that provoked the attack have been paid, but before the application of that action’s effect upon the game state.

I am unsure as to what the "cost"and what the "application" is in the case of a skill test.

Example. I have Milan Christopher (+1 intellect) and make an investigation action while engaged with an enemy. Now, say I assign the damage from the attack of opportunity to Milan and Milan is therefore destroyed. At what point does this happen? Is this after I draw from the bag and determine the test result (thus Milan's intellect bonus still applies to the test) or does Milan die before I resolve the test?

Thanks!

In this case, the cost would be using the action to investigate, so you would assign the damage, then make the test.

What are the costs of initiating an investigation test?

21 minutes ago, Meretrix said:

What are the costs of initiating an investigation test?

You usually do not initiate a test, but an action that involves a test. The cost for that is your action (or the cost for the effect that contains the investigation). Actions are a form of resource, because of that effects can cost more than 1 action.

The cost of a simple "investigate" action is the 1 action it costs to perform the test. The entire skill test is after the attack of opportunity. DrMilan would be dead and no longer give his +1.

Generally for each Action, it's just triggering the Action. Whether that's a Rulebook Action, an Action or Fast Trigger on a card you can interact with, or something else that allows you to take an Action. A few things will have "additional costs" but these are explicit by other cards, like the Rougarou or the Orne Library.

Thanks everyone for the help!

More generally, see "Costs" in the RRG (p7).

It's a card's resource cost, anything listed before a colon in a card's ability, and/or anything described as an "an additional cost" (though additional costs sometimes have their own timing causing them to be paid after Attacks of Opportunity).