[RPG] How to balance giving the party a teamwork feat

An all spell caster party already has balance built into it.

They can pretty much do whatever they want. Situation arises where they need a lot of meat shields? Summoning spells or animating the dead. A bunch of magical weapons and armor are coming their way and threatening to beat them dead? Dispel and Antimagic Zones. Lost of casters attacking them? Counterspell!

Spell casters are incredibly versatile. Because of this, balance is going to be based on how many spells they're casting per encounter, as well as the availability of wands, rods, scrolls and staves.

After that, just leave it up to them. You may find sending a half dozen orcs at them is a joke and they easily blow them away. So the next group staggers their approach to not get caught by AoE.

Ultimately, they're going to either breeze through situations by expending spells like crazy and saving nothing, or they'll think their way through problems and be conservative. The balance will happen. It just depends on how you run the encounters and whether or not they seek a resting zone when they're depleted, or just getting on towards depleted.

You probably want to split the cost of a ring of tactical precision (Ultimate Equipment 175) (11,000 gp; 0 lbs.) or two. Your buddy wears the ring for an hour, picks one of his teamwork feats, and gives the ring to you. While you're wearing the ring, for 1 day you can use that teamwork feat your buddy picked. (He doesn't lose the feat or anything, though.) You benefit from the teamwork feat your buddy picked, but can only benefit from the teamwork feat in conjunction with your buddy. (For instance, were the fighter that possesses a teamwork feat to have imbued two rings with the same teamwork feat and given one to the cleric and and another to the rogue, the fighter and the rogue in tandem could use the teamwork feat as could the fighter and the cleric, but not the cleric and the rogue.)

Much more expensive—and annoying—is the helmet of the golden general (Ultimate Equipment 357-8) (62,000 gp; 3 lbs.), an intelligent item which can grant the wearer the creator's choice of three teamwork feats, which "[t]he wearer can use... as if [they] were on his feat list," presumably ignoring prerequisites entirely. The feats are chosen when the helmet's created and can't be changed afterward. But during battle the helmet provides constant verbal color commentary and condescending coaching. I suggest immediately somehow muting the central ruby where the words come out.