So... there have been a couple of things that made me think of clarifying something. Basically -- when dice can be used. I read somewhere once something that went like "Say 'Yes' or roll dice". Basically, it meant that if everyone agreed to something, there was no need to roll dice to resolve it -- but if someone did not, that's what dice were for. This, of course, doesn't include external effects.

As an example, I once narrated my Mage holding a pistol while holding a jacket in his other hand over it, occluding a view of the pistol. There was Much Angst when the pistol was used. Anyone was free to make a Investigation (or other appropriate roll) to notice the hidden gun -- at which point I probably would have made a Larceny roll and the successes would be compared.

A more immediate example would be found here: Where my character Asa is lying (more than once) to another character, Matthew Greene. I've blatantly stated in narration that my character is lying. At this point, roadnottaken was free to either:
a) have his character accept the lie at face value
b) roll to see if his character noticed the lie (at which point I would have rolled to make the lie and compared successes)

I realize that play by post may be new for some, and some of us are used to doing things this way, so this doesn't really come up until there is Much Angst to be had.

You can take things at face value in a consensual agreement of the facts, or roll dice to resolve a conflict/deception/etc. If you decide to accept what is presented, and not roll dice, there should not be Much Angst

This is just me, as a player, trying to explain things Your Storyteller, of course, is the final arbiter of any such agreement or conflict resolution.