diff --git a/swagger.yaml b/swagger.yaml
index 207e85c..a9a4980 100644
--- a/swagger.yaml
+++ b/swagger.yaml
@@ -46,6 +46,7 @@ paths:
           in: "path"
           required: true
           type: "integer"
+          enum: [0, 1, 2, 3, 4, 5, 6, 7]
           description: "ID of the relay to check status."
       responses:
         200: