How to get root motion animation displacement before playing it?

My issue is like this:

I want to play a climbing ledge root motion animation. My animator made it start from X centimeter to the ledge. So I have to place the character at the location that is X centimeters to the ledge before I play the animation.

I’d like to retrieve this X value at runtime, not ask my animator and hard code it.

How could I get such informations from the animation (montage) before I play it.

P.S. I’m working mostly in C++ and play animation montage using UAnimInstance::Montage_Play.

Thanks