diff --git a/lib/types.nix b/lib/types.nix
index 58e90f6..acb3bd6 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -7,7 +7,7 @@
 in rec {
   # The runtime object
   runtimeType = with yants;
-    struct "runtime" {
+    openStruct "runtime" {
       # The version of the runtime
       version = option string;