diff --git a/packages/snaps-sdk/src/jsx/validation.test.tsx b/packages/snaps-sdk/src/jsx/validation.test.tsx
index 9cb0c285ef..e1190dafda 100644
--- a/packages/snaps-sdk/src/jsx/validation.test.tsx
+++ b/packages/snaps-sdk/src/jsx/validation.test.tsx
@@ -61,11 +61,11 @@ import {
 } from './validation';
 
 describe('KeyStruct', () => {
-  it.each(['foo', 42])('validates a key', (value) => {
+  it.each(['foo', 'bar'])('validates a key', (value) => {
     expect(is(value, KeyStruct)).toBe(true);
   });
 
-  it.each([null, undefined, {}, []])('does not validate "%p"', (value) => {
+  it.each([42, null, undefined, {}, []])('does not validate "%p"', (value) => {
     expect(is(value, KeyStruct)).toBe(false);
   });
 });
diff --git a/packages/snaps-sdk/src/jsx/validation.ts b/packages/snaps-sdk/src/jsx/validation.ts
index 73cfdf101e..e7b026a95f 100644
--- a/packages/snaps-sdk/src/jsx/validation.ts
+++ b/packages/snaps-sdk/src/jsx/validation.ts
@@ -68,7 +68,7 @@ import type {
 /**
  * A struct for the {@link Key} type.
  */
-export const KeyStruct: Describe<Key> = nullUnion([string()]);
+export const KeyStruct: Describe<Key> = string();
 
 /**
  * A struct for the {@link StringElement} type.