diff --git a/src/openrpc/alchemy/transfers/transfers.yaml b/src/openrpc/alchemy/transfers/transfers.yaml
index dbbee01fb..001567b78 100644
--- a/src/openrpc/alchemy/transfers/transfers.yaml
+++ b/src/openrpc/alchemy/transfers/transfers.yaml
@@ -160,6 +160,8 @@ methods:
         required: true
         schema:
           type: object
+          required:
+            - category
           properties:
             fromBlock:
               type: string