Is it ok to mod if its just singleplayer not cheat

A bit of an odd question i know and talking about modding is off limits, but i felt the need to ask before trying

i’ve been wanting to make a mod for halo wars for a little bit now, nothing to do with multiplayer just something that changes up the units for skirmish and campaign, nothing which changes achievements or unlocks and definitely NOT something i would use in multiplayer

i was wondering is it ok to do this? i also wouldn’t be releasing any mod publicly it would just be for myself, offline to mess about in the skirmish and campaign mode [adding new units to factions mainly]

sorry if this is inappropriate area i just didnt know where to ask and wanted to be ‘safe’ as to whats ok and whats not

edit:
i also think i should point out i havent started attempting to mod yet, and dont intend on starting until i have all the facts and an ok [or if its not ok to start i simply wont, as much as i want to make my own high quality content mod for the game i dont want to risk losing my games or xbox]

Hey OP, we don’t actually allow discussing modding or modded content here on Waypoint. I think as long as your plans don’t involve taking or attempting to take modifications into an online environment, you should be relatively ok.