diff --git a/gui/buy_menu/shop.gd b/gui/buy_menu/shop.gd
index 562d147..ea41fe6 100644
--- a/gui/buy_menu/shop.gd
+++ b/gui/buy_menu/shop.gd
@@ -17,11 +17,14 @@ func buy(player_id: int, weapon: WeaponResource) -> void:
 	match weapon.slot:
 		"ability":
 			slot = weapon_system.get_empty_ability_slot()
+			if not weapon_system.can_add_ability(weapon.get_gid(),slot):
+				return
 		var anything:
 			slot = anything
+			if not weapon_system.can_add(slot):
+				return
+	
 	
-	if not weapon_system.can_add(slot):
-		return
 	
 	var player_data = Session.player_data[player_id]
 	player_data["money"] -= weapon.cost
diff --git a/systems/weapon_system/weapon_resource.gd b/systems/weapon_system/weapon_resource.gd
index c10ad2c..4385827 100644
--- a/systems/weapon_system/weapon_resource.gd
+++ b/systems/weapon_system/weapon_resource.gd
@@ -7,3 +7,7 @@ class_name WeaponResource
 @export var dropped_scene: PackedScene
 @export var weapon_system_scene: PackedScene
 @export var slot: StringName
+
+func get_gid() -> StringName:
+	var path_split: PackedStringArray = resource_path.split("/")
+	return path_split[len(path_split)-1].trim_suffix(".tres")
diff --git a/systems/weapon_system/weapon_system.gd b/systems/weapon_system/weapon_system.gd
index 8ccbd16..47e9ebb 100644
--- a/systems/weapon_system/weapon_system.gd
+++ b/systems/weapon_system/weapon_system.gd
@@ -79,6 +79,12 @@ func get_empty_ability_slot() -> StringName:
 		return "ability_third"
 	return "ability_first"
 
+func can_add_ability(ability: StringName, slot: StringName) -> bool:
+	for ability_slot in ["ability_first","ability_second","ability_third"]:
+		if slots[ability_slot] != null and slots[ability_slot].registry_entry == ability:
+			return false
+	return can_add(slot)
+
 func switch(to: StringName, exit: bool = true):
 	if slots.has(to) == false or slots[to] == null or slots[to] == current_state or (multiplayer.get_remote_sender_id() != 1 and is_multiplayer_authority() == false):
 		return