diff --git a/src/arclet/alconna/sistana/model/receiver.py b/src/arclet/alconna/sistana/model/receiver.py
index 7474df8a..722d4fad 100644
--- a/src/arclet/alconna/sistana/model/receiver.py
+++ b/src/arclet/alconna/sistana/model/receiver.py
@@ -35,3 +35,13 @@ def receive(self, get: RxGet[list[T]], put: RxPut[list[T]], data: T) -> None:
             put([data])
         else:
             put([*v.value, data])
+
+
+class ConstraintRx(Generic[T], Rx[Any]):
+    value: T
+
+    def __init__(self, value: T):
+        self.value = value
+
+    def receive(self, get: RxGet[Any], put: RxPut[T], data: Any) -> None:
+        put(self.value)