diff --git a/collects/scribblings/reference/class.scrbl b/collects/scribblings/reference/class.scrbl
index b88dd550ef..d9aea7a821 100644
--- a/collects/scribblings/reference/class.scrbl
+++ b/collects/scribblings/reference/class.scrbl
@@ -1494,9 +1494,13 @@ resulting trait are the same as for @racket[trait-sum], otherwise the
 @defform/subs[
 #:literals (field init init-field inherit inherit-field super inner override augment augride absent)
 
-(class/c member-spec ...)
+(class/c maybe-opaque member-spec ...)
 
-([member-spec
+([maybe-opaque
+  (code:line)
+  (code:line #:opaque)]
+
+ [member-spec
   method-spec
   (field field-spec ...)
   (init field-spec ...)
@@ -1538,6 +1542,12 @@ for writing method contracts.
 
 Methods and fields listed in an @racket[absent] clause must @emph{not} be present in the class.
 
+A class contract can be specified to be @emph{opaque} with the @racket[#:opaque]
+keyword. An opaque class contract will only accept a class that defines
+exactly the methods and fields specified by the contract. A contract error
+is raised if the contracted class contains any methods or fields that are
+not specified.
+
 The external contracts are as follows:
 
 @itemize[