I was researching and trying to discern if a wish spell could give a PC a skill he does not have. I don't see anything that states it can or cannot but when compared to some of the things a wish could grant it would seem like a feasible option. Does anyone know if there is a rule for this already in place or if this would be up to DM discretion?
Wish has a very specific, limited list of things it definitely can do safely:
Duplicate spellcasting (up to certain levels based on class)
Undo many spells and heal many afflictions, up to and including death, as stated in those spells and in wish itself
Create a nonmagical item of up to 25,000 gp
Create a magical item or upgrade a magical item1
Grant inherent bonuses to ability scores
So these are the things we know wish can do, and that will not be twisted or come at costs greater than those listed in the spell.
Everything else is covered by
You may try to use a wish to produce greater effects than these, but doing so is dangerous. (The wish may pervert your intent into a literal but undesirable fulfillment or only a partial fulfillment.)
So ultimately, yes, it is purely up to the DM.
- The ability to create a magical item is listed in a separate bullet from the one for creating nonmagical items, and does not list any cost limit as the nonmagical version does. Whether this means that wish has no limit on magical item creation is a matter of some debate. Ask your DM.