diff --git a/configs/nixos/registry/route.nix b/configs/nixos/registry/route.nix
index c1ef4e7..b4ff6dc 100644
--- a/configs/nixos/registry/route.nix
+++ b/configs/nixos/registry/route.nix
@@ -7,10 +7,9 @@
     }
     {
       assertion = entries:
-        let
-          ports = lib.concatMap (entry: entry.value.udp.ports) entries;
-        in
-        builtins.length (lib.unique ports) == builtins.length ports;
+        lib.registry.predicates.uniqueValue (entry: entry.value) (
+          lib.concatMap (entry: map (port: entry // { value = port; }) entry.value.udp.ports) entries
+        );
       message = "Route UDP ports must be unique.";
     }
   ];