I created a simple test Narrative event and everything works as expected with it aside from one thing (so far). The Narrative system seems to ignore Prerequisites on on choices. This may be due to me misunderstanding what it does. I tried to create a narrative choice that would be disabled, not available, or does not appear. I've tried the Failure Flags being set to all combinations of none, discard, and/or disabled but it does not seem to have an effect. In the example pictured below I attempted to put a prerequisite on the narrative choice that shouldn't be possible (I've tried a few different ones) the one pictured is territory count being greater than or equal to 5. The event, due to it being in its own category, fires at around turn 9. When the narrative event fires choice 2 is selectable and it does give the specified 100 influence. Is there a way to have prerequisites or conditions on a narrative choice?

Some of the parameters have tool tips which is nice, but most do not. Would it be possible to have someone explain what the following are:

Prerequisites:

-Failure Flags (none, disable, discard)

Narrative Event Effect:

- Reversible

Hello!
The FailureFlags field correspond to the behavior when the prerequisite fail.

Discard hide the choice and disable greyout the choice (though I'm not sure if "Disable" still works as we never used it in the end).

In your example, if the FailureFlag is set to Discard, the choice should be hidden when the Empire selected in the Empire variable hold less than 5 territories.

On the choice, "Instant" means "do we need de revert the choice once the narrative event end" (it is not well named).

On the effect, the "Reversible" is the same as Instant but on an effect by effect basis.

I'll try to add more tooltips in the future

That was the effect I was expecting, but any combination I tried the choice was available and selectable.

You also need to add to the narrative event choice some Prerequisite : 

Adding these for example : 

Mean that this choice will only be valid if the CapitalCity (that you selected in the Variable part upper) is building Stonehenge.