diff --git a/src/rpc-handler.test.ts b/src/rpc-handler.test.ts
index c64fd0472..b467fbd29 100644
--- a/src/rpc-handler.test.ts
+++ b/src/rpc-handler.test.ts
@@ -77,7 +77,7 @@ describe('keyringRpcDispatcher', () => {
     };
 
     await expect(handleKeyringRequest(keyring, request)).rejects.toThrow(
-      'At path: params.id -- Expected a string, but received: undefined',
+      'At path: params.id -- Expected a value of type `UuidV4`, but received: `undefined`',
     );
   });
 
diff --git a/src/utils.ts b/src/utils.ts
index 593f59025..75d22dd4d 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,12 +1,15 @@
-import { assert, pattern, string } from 'superstruct';
+import { assert, define } from 'superstruct';
 import type { Struct } from 'superstruct';
 
+const UUID_V4_REGEX =
+  /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/iu;
+
 /**
  * UUIDv4 struct.
  */
-export const UuidStruct = pattern(
-  string(),
-  /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/iu,
+export const UuidStruct = define<string>(
+  'UuidV4',
+  (id: unknown): boolean => typeof id === 'string' && UUID_V4_REGEX.test(id),
 );
 
 /**