diff --git a/federation/src/graphql/api/1_0/model/OpenConnectionCallbackArgs.ts b/federation/src/graphql/api/1_0/model/OpenConnectionCallbackArgs.ts
index 461f6c3d7..cfd5062c9 100644
--- a/federation/src/graphql/api/1_0/model/OpenConnectionCallbackArgs.ts
+++ b/federation/src/graphql/api/1_0/model/OpenConnectionCallbackArgs.ts
@@ -1,10 +1,13 @@
+import { IsString } from 'class-validator'
 import { Field, InputType } from 'type-graphql'
 
 @InputType()
 export class OpenConnectionCallbackArgs {
   @Field(() => String)
+  @IsString()
   oneTimeCode: string
 
   @Field(() => String)
+  @IsString()
   url: string
 }