Furtive Caster

General feat (Prerequisite: level 4+, Spellcasting or Pact Magic feature) — Campaign homebrew for Heretics of the Old Gods

In a place that hangs mages, the ones who last are the ones whose hands never look like they’re casting. You gain the following benefits:

• Ability Score Increase. Increase your Dexterity or Charisma by 1, to a maximum of 20.
• Practiced Concealment. When you gain this feat, choose Sleight of Hand or Deception. You gain proficiency in that skill, or Expertise in it if you’re already proficient. This is your concealment skill.
• Furtive Casting. Whenever you cast a spell, you can try to cast it without anyone noticing you did — palming the somatic components, swallowing the incantation, masking the tell. Make a check with your concealment skill against a DC of 10 + the spell’s level (a cantrip is level 0, so DC 10). The spell is cast either way; the check only determines whether you’re seen doing it. On a success, no observer can tell that you cast a spell or that magic came from you, and the casting can’t be met by counterspell or any reaction that requires seeing a creature cast a spell. On a failure, the spell works normally but your casting is obvious — every onlooker knows it was you. The spell’s slot and action are spent regardless of the result. Making this check is part of casting the spell and costs no additional action.