diff --git a/CONFIGURATION.md b/CONFIGURATION.md
index 8d115978..05982c54 100644
--- a/CONFIGURATION.md
+++ b/CONFIGURATION.md
@@ -47,8 +47,8 @@ modules:
 ### `<http_probe>`
 ```yml
 
-  # Accepted status codes for this probe. Defaults to 2xx.
-  [ valid_status_codes: <int>, ... | default = 2xx ]
+  # Accepted status codes for this probe. List between square brackets. Defaults to 2xx.
+  [ valid_status_codes: [<int>, ...] | default = 2xx ]
 
   # Accepted HTTP versions for this probe.
   [ valid_http_versions: <string>, ... ]