In Sharn, there are many spells and magical effects that people use in their day-to-day lives. Some of them are intrinsic to the city, built in to the walkways, buildings, and streetlamps. Some of them are available as potions, oils, and simple magical trinkets to anyone who can afford them. And some of them are powerful spell effects only a wizard or artificer of sufficient strength is capable of.

In D&D terms, spells of 3rd level or below are available, or even in common use, depending on a person's means. Any effect of 4th level and above is powerful, rare, expensive, and beyond a character's ability to cast. To use such powerful effects, characters need to seek out patrons or pay spellcasters to cast for them.

Minor effects like Prestidigitation are so simple, anyone with a rank in Cast can use them. Many variable effects of the spells are based on a Cast check (if you're casting the spell or using a wand) or Tier check (if you're using it in a potion or other item), made when you use it.

Many of these spells don't have specific mechanical effects, but they might affect (or enable) Action rolls or position, or generate Heat if they're loud, flashy, or illegal. If one of these spells is cast on a Player Character, they will usually be able to Resist it, or at least mitigate its effect. A spell expiring or being dispelled is a common consequence or Gift of the Traveler.

Spells will sometimes contain descriptors of range, time, area, targets, and damage. These have some mechanical effects, but mostly determine how the spell interacts with the Fiction of the game. It's up to the GM to determine how these factors affect position, effect, and consequences. Failures on spell rolls might mean reduced or nullified effects, unwanted attention, or collateral damage. Some spells (especially spells contained in potions) will not have a chance to fail outright, and indeed might not require rolls at all. A healing potion, for example, would only require a roll in the most dire of circumstances (and would probably be Controlled/Standard, at that).

Almost all of the time, when a spell calls for an action roll to determine its effects, use the Cast action. But depending on the spell and how it's used, other actions might be applicable. Such as Skirmish for a melee attack spell or Perceive for a detection spell.