"Right, sorry.
It's easier to talk about what they can't do, so - limits of magic.
You do have to have a resonance of the relevant Realm on your side to pull off any kind of magical effect - other than the few we've managed to refine down into spells, and those all started as rituals of one Realm or another.
There are an enormous list of resonances - and dissonances, specific Realms are also bad at specific things - but if you have the whole of magic to play with, you can generally find somewhere your effect will fit. Most magicians only learn one or two Realms because it's a time consuming study and it's harder to keep them all straight in your head if you pick up too many, although some people manage it.
There are also actual limits to all magic. The most obvious one is life - dead people are dead. You can talk to them in a very time limited way, but you can't bring them back once the body's too damaged to keep housing the soul.
Magic is also considerably better at offence than defence, at least on a personal level. You can enchant a castle, you can hide information, you can have contingent offense, but nothing magical will make you completely immune to someone hitting you with a stick - more resilient, sure, but not immune. It's also very hard to stop offensive magic - if someone pushes you back with magical force, that will take effect, whatever else you have going on.
Getting inside someone's mind requires consent. You can make people feel things, you can make bad things happen if they do certain things or don't do certain things, but you can't actively force someone to do something or not to do something; you can obtain some kinds of knowledge from people, the knowledge of how to make certain artisan items is a good example, but you can't see what they're thinking. Rituals that let you change someone's memory, or personality, require active consent and are fundamentally controlled by the target, rather than the caster.
You can't directly create things - you can combine things into other things, you can call in existing agreements with the Realms to supply things, but objects and Heralds are not directly created by magic.
Portals can only be opened between the world and pockets of the Realms, not different places within the world, by ritual magic directly - there's clearly a way to combine with artisanry and do it because the Sentinel Gate does that, but nobody has been able to make another one.
You can't make something totally invisible, and the offense over defence thing works for divination magic too - you can conceal the nature of things, but not that you've concealed something.
Uh, what else. There's the Law of Essence which is the really annoying one, basically the weirder and flashier the effect, the less likely it's going to work; usually it's easier to do something in a way that has plausible deniability? Oh, and magic basically doesn't work on the raw materials that get processed into white granite, mithril, weirwood and ilium - I'm fairly sure this is the universe just being inconvenient for the sake of it, I've heard lots of theories but I'm not deeply convinced by any of them.
There are loads of other weird little limits, like what exactly you can do to an army or a fortification, which kinds of skill you can share with magic, but those are the main ones.
Artisanry - I'm even less of an expert on, Prudentia?"