Creating a Feat with number of uses based on abilityu modifier

[Lonestar190]

Hi all,

I am trying to make a custom class and one of the abilities is:

When a Bonded Companion within 10 feet is hit by an attack, use your reaction to reduce the damage by 1d10 + Constitution modifier. If this reduces the damage to zero the attack is entirely negated. Uses per long or short rest: Constitution modifier.

FG is not picking this up as an action and giving me the pips for number of uses. How can I write this to work (if at all?).

Thanks in advance.

[Laerun]

This might need an extension or to be hard coded.

[Zacchaeus]

There's no wording that will pick this up and automate it, so the user would need to set it up in the actions tab and use preparation mode to limit the number of uses.