What about adding documentation/help in the metadata documents?

Right now, the only way to get information about service operations input parameters is on the Dallas portal.

For example, we can see the following for the CategoryId parameter of "AP Online - AP" :

The news category ID.

URL query parameter name
CategoryId

Sample value(s)
31990|31991|31992

Usage
<serviceUrl>?CategoryId=<value>

and this for MediaOption

0 for no pictures, 1 for pictures.

URL query parameter name
MediaOption

Usage
<serviceUrl>?MediaOption=<value>

In addition, the combobox for MediaOption proposes the two supported values (0 and 1).

It would be great if we could get this kind of information right from metadata.
What about adding dr:Help and dr:SupportedValues attributes on FunctionImport/Parameter?