diff --git a/doc/ref/spec.md b/doc/ref/spec.md
index a022dc1..cbf0f87 100644
--- a/doc/ref/spec.md
+++ b/doc/ref/spec.md
@@ -1694,7 +1694,7 @@
 
 ```
 Functions
-len       required  close     open
+len       close and or
 
 Types
 null      The null type and value