Yes you can in beautiful markdown language at https://<yourappurl>/rest-doc/ :)
It's currently only possible at the operation level (and resource level) in the configuration of your REST service.
my example:
Use markdown to format it correctly!
In my opinion it should be documented at the responses (instead of "succesful operation" ) but that is not currently possible.
Do you mean something like the information that you can find in the rest doc of your app: http://yourapp.com/rest-doc/