diff --git a/api/client-server/whoami.yaml b/api/client-server/whoami.yaml
index 7374ab5a..4d9d6ceb 100644
--- a/api/client-server/whoami.yaml
+++ b/api/client-server/whoami.yaml
@@ -43,6 +43,7 @@ paths:
               }
           schema:
             type: object
+            required: ["user_id"]
             properties:
               user_id:
                 type: string