diff --git a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonPayloadValidatorSpec.scala b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonPayloadValidatorSpec.scala
index e72cb39..bf68b2a 100644
--- a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonPayloadValidatorSpec.scala
+++ b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonPayloadValidatorSpec.scala
@@ -31,17 +31,20 @@ object JsonPayloadValidatorSpec extends FunSuite {
         |}
         |
         |structure OpInput {
+        |  @required
         |  @jsonRpcPayload
         |  data: String
         |}
         |
         |structure OpOutput {
+        |  @required
         |  @jsonRpcPayload
         |  data: String
         |}
         |
         |@error("client")
         |structure OpError {
+        |  @required
         |  @jsonRpcPayload
         |  data: String
         |}
@@ -76,6 +79,7 @@ object JsonPayloadValidatorSpec extends FunSuite {
         |}
         |
         |structure NestedStructure {
+        |  @required
         |  @jsonRpcPayload
         |  data: String
         |}
diff --git a/modules/smithy/src/main/resources/META-INF/smithy/jsonrpclib.smithy b/modules/smithy/src/main/resources/META-INF/smithy/jsonrpclib.smithy
index 6303ce1..1a0505b 100644
--- a/modules/smithy/src/main/resources/META-INF/smithy/jsonrpclib.smithy
+++ b/modules/smithy/src/main/resources/META-INF/smithy/jsonrpclib.smithy
@@ -36,11 +36,11 @@ string jsonRpcNotification
 
 /// Binds a single structure member to the payload of a jsonrpc message.
 /// Just like @httpPayload, but for jsonRpc.
-@trait(selector: "structure > member", structurallyExclusive: "member")
+@trait(selector: "structure > member[trait|required]", structurallyExclusive: "member")
 @traitValidators({
-    "jsonRpcPayload.OnlyTopLevel": { 
-        message: "jsonRpcPayload can only be used on the top level of an operation input/output/error.", 
-        severity: "ERROR", 
+    "jsonRpcPayload.OnlyTopLevel": {
+        message: "jsonRpcPayload can only be used on the top level of an operation input/output/error.",
+        severity: "ERROR",
         selector: "$allowedShapes(:root(operation -[input, output, error]-> structure > member)) :not(:in(${allowedShapes}))"
     }
 })