NSHipster has good comments on this. http://nshipster.com/documentation/
As for delegates its good to inform whoever is conforming to the protocol of when the messages will be sent, so for example:
/*!
* @field processing Flag indicating that the operation is currently in process
*/
@property (readonly) BOOL processing;
/*!
* Sent right after the parser began
*
* @param parser (Something about the parser)
*/
-(void)parserDidStart:(SCParser *)parser;
/*!
* Sent after the parser opens the given tag (maybe some hints as to what the delegate may do)
*
* @param parser (Words about the parser)
* @param tag (Something about the tag)
*/
-(void)parser:(SCParser *)parser didOpenTag:(SCTag *)tag;
There's other tags which are helpful such as @return and @warning. VVDocumenter is quite helpful so I would recommend installing that.