Putting detailed REST error message in HTTP Warning header, good/bad idea?

Question

We are developing a standard REST service using HTTP status codes as its response code if something went wrong. (e.g. invalid user input would return \"400 Bad Request\" to

Answer 1

If this proposal is accepted, it presents an alternative for sending detail error messages. [http://tools.ietf.org/html/draft-nottingham-http-browser-hints]

Despite it being an I-D, it's fairly stable lately, and I see no problem with building your own implementation. (I have done.)