mystic_level_up_chance_effect

mystic_level_up_chance_effect = {
	if = {
		limit = {
			NAND = {	
				has_trait = lifestyle_mystic
				has_trait_xp = {
					trait = lifestyle_mystic
					value >= 100
				}
			}
			is_alive = yes
		}
		random = {
			chance = $CHANCE$
			ai_mystic_lifestyle_rank_up_effect = yes

			#Used by physician_rank_up_tooltip_effect, to be shown in treatment outcome...
			set_variable = { name = physician_level_up value = flag:mystic days = 15 }

			#...or in notification
			if = {
				limit = {
					liege ?= { this != scope:sick_character }
				}
				liege = {
					send_interface_message = {
						type = event_court_physician_good
						title = physician_level_up_chance_effect.t
						left_icon = scope:physician
						physician_rank_up_tooltip_effect = yes
					}
				}
			}

			#Have a tiny chance to become witch
			hidden_effect = {
				if = {
					limit = {
						is_ai = yes
						NOR = {
							any_secret = { type = secret_witch }
							has_trait = witch
						}
					}
					random = {
						modifier = {
							factor = 0
							ai_zeal >= medium_positive_ai_value
						}
						modifier = {
							factor = 2
							ai_zeal <= high_negative_ai_value #high and not medium because mystic traits already remove some ai_zeal
						}
						chance = 5
						give_witch_secret_or_trait_effect = yes
					}
				}
			}
		}
	}
}

As written in game/common/scripted_effects/20_health_effects.txt.