diff --git a/cup.schema.json b/cup.schema.json
index b4dddec..ed441e8 100644
--- a/cup.schema.json
+++ b/cup.schema.json
@@ -36,7 +36,7 @@
         },
         "refresh_interval": {
             "type": "string",
-            "description": "The interval at which Cup should check for updates. Must be a valid cron expression. Reference: https://github.com/Hexagon/croner-rust#pattern",
+            "description": "The interval at which Cup should check for updates. Must be a valid cron expression. Seconds are not optional. Reference: https://github.com/Hexagon/croner-rust#pattern",
             "minLength": 11
         },
         "registries": {
diff --git a/docs/src/content/docs/configuration/automatic-refresh.mdx b/docs/src/content/docs/configuration/automatic-refresh.mdx
index b510300..a589379 100644
--- a/docs/src/content/docs/configuration/automatic-refresh.mdx
+++ b/docs/src/content/docs/configuration/automatic-refresh.mdx
@@ -4,9 +4,9 @@ Cup can automatically refresh the results when running in server mode. Simply ad
 
 ```jsonc
 {
-  "refresh_interval": "0 0,30 * * * *" // Check twice an hour
+  "refresh_interval": "0 */30 * * * *", // Check twice an hour
   // Other options
 }
 ```
 
-You can use a cron expression to specify the refresh interval. The reference is [here](https://github.com/Hexagon/croner-rust#pattern)
\ No newline at end of file
+You can use a cron expression to specify the refresh interval. Note that seconds are not optional. The reference is [here](https://github.com/Hexagon/croner-rust#pattern)