diff --git a/src/schema.ts b/src/schema.ts
index 359396b..a5782b4 100644
--- a/src/schema.ts
+++ b/src/schema.ts
@@ -27,6 +27,7 @@ export const definitionSchema = {
         properties: {
           address: {
             type: 'string',
+            pattern: '^(|0x[a-fA-F0-9]{40})$',
           },
         },
         required: ['address'],