update_confidants_effect

update_confidants_effect = {
	if = {
		limit = {
			has_perk = confidants_perk
		}
		remove_all_character_modifier_instances = confidants_perk_modifier
		save_temporary_scope_as = confidant_scope 

		set_variable = {
			name = current_confidants_perk_value
			value = 0
		}
		
		if = {
			limit = {
				exists = var:current_confidants_perk_value
			}
			every_relation = {
				type = friend
				add_to_temporary_list = confidant_friend_list
			}
			every_in_list = {
				list = confidant_friend_list
				scope:confidant_scope = {
					if = {
						limit = {
							exists = var:current_confidants_perk_value
							var:current_confidants_perk_value < confidants_max
						}
						change_variable = {
							name = current_confidants_perk_value
							add = 1
						}
						add_character_modifier = {
							modifier = confidants_perk_modifier
						}
					}
				}
			}
			remove_variable = current_confidants_perk_value
		}
	}
}

As written in game/common/scripted_effects/00_diplomacy_perk_effects.txt.