diff --git a/website/docs/language/functions/sum.mdx b/website/docs/language/functions/sum.mdx
index 2528240b9f..9de4d61e47 100644
--- a/website/docs/language/functions/sum.mdx
+++ b/website/docs/language/functions/sum.mdx
@@ -9,6 +9,8 @@ description: |-
 
 `sum` takes a list or set of numbers and returns the sum of those numbers.
 
+`sum` will fail if given an empty list or set.
+
 ## Examples
 
 ```