diff --git a/unilabos/registry/devices/work_station.yaml b/unilabos/registry/devices/work_station.yaml
index b6257a3..cb119f5 100644
--- a/unilabos/registry/devices/work_station.yaml
+++ b/unilabos/registry/devices/work_station.yaml
@@ -242,6 +242,8 @@ workstation:
           type: object
         type: AGVTransfer
       AddProtocol:
+        placeholder_keys:
+          vessel: unilabos_resources
         feedback: {}
         goal:
           amount: amount