I’m trying to get a summon steed spell up and running, but can’t figure out how to make the summoned horse already tamed/ridable. I can’t seem to find a “tame” or “mountable” tag to just slap on, is there a way to make either a non-pet mountable or have it spawn as a pet?
Maybe not ideal, but since you need feed to tame a horse you happen upon naturally, maybe your spell could just summon fodder as well?
Then you could just feed it, it’d be happy & tame and all is well.
Additionally, you could leave it as it is, knowing any horse summoned will be wild and the spell just serves up a horse. You’ll have to deal with it in more mundane ways. 
Spawning fodder as well was my first thought, but I ran into trouble while trying to both summon and spawn_item in the same effect. wouldn’t work when I tried to call 2 different effects (summon and spawn_item) and I can’t find any other examples in the code that would do both. I also might just leave it as is and extend the duration to make up for having to feed it.