The D&D Find Familiar spell has a long description, but it ends with the following:

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.

This mod adds spellcasting via familiar to BG3.

While you have an active familiar, you will also have a Cast Near Familiar passive toggle available. While in turn-based mode with the toggle enabled, your melee spells that are not weapon attacks will be able to target around your familiar.

The toggle is on by default and usually doesn't impede regular casting around the summoner, but you may need to turn it off to be able to target some very large creatures.


Cooldown Removal
BG3 added a once per short rest cooldown to Find Familiar and similar spells, which doesn't exist in D&D. This mod removes such cooldowns.


Minor Fixes

• Makes it possible to summon Scratch as the first thing you do after leaving camp, instead of having to use some random other action first to unstick the summoning spell.
• Makes summoning Shovel take an Action like all the other familiar-summoning spells, instead of being a free action.
  

Extensibility
Other mods can register their own summons as familiars, or spells as valid to cast via familiar, if they don't qualify automatically. The optional files serve as samples of API use.

Help via Familiar shows how to register a spell for use via familiar if it doesn't qualify automatically.

Wildfire Druid Support shows how to register summons as familiars, making Wildfire Spirit count as a familiar for this mod's purposes once the Enhanced Bond feature is unlocked. This provides a more limited form of the feature compared to D&D, but better than nothing. It works with both Havsglimt's and Kingdomyoshi's versions of the subclass.




Compatibility

Works with Find Familiar, Pact of the Chain familiars, Scratch, Boo, Shovel, as well as any mod-added summons that follow the game's naming conventions for these spells.

Mods that register their own summons or spells for use with this mod should be loaded after (placed below) it.

This mod patches the target conditions of hundreds of spells, including ones added by mods. This makes spells from other mods support use from familiars without them having to even be aware of this mod.

Patching is done dynamically on startup via Script Extender and shouldn't cause any conflicts with other mods as long as they're properly written. I can't guarantee this won't break things if a spell has syntax errors. Unfortunately BG3 is quite lenient in accepting garbage input, and not all mods are properly written.


Known Issues

Scratch's short rest cooldown will not be removed immediately if you were already able to summon him. To get rid of it, give his ball to another character, short rest, save, load, then give the ball back to the original character.

When a character has multiple familiars (such as from the Flock of Familiars spell) the reaction cost of casting via familiar doesn't work reliably. It may be paid by multiple nearby familiars, or not enforced at all.

Game issue: Every time you summon a temporary character - familiar or otherwise - it leaves behind a lot of database entries in the save game, which gradually increases load times. The Database Cleaner mod can be used to clean up most of the remains.