diff --git a/lib/json-schema/util/uri.rb b/lib/json-schema/util/uri.rb
index b6b3be3d..9a8cbeb7 100644
--- a/lib/json-schema/util/uri.rb
+++ b/lib/json-schema/util/uri.rb
@@ -4,6 +4,7 @@
 
 module JSON
   module Util
+    # @api private
     class URI < Addressable::URI
       SUPPORTED_PROTOCOLS = %w(http https ftp tftp sftp ssh svn+ssh telnet nntp gopher wais ldap prospero)