I guess I found the answer.
http://www.phpdoc.org/docs/latest/references/phpdoc/tags/property.html
The @property tag is used in the situation where a class contains the __get() and __set() magic methods and allows for specific names.
Also:
The @method tag is used in situation where a class contains the __call() magic method and defines some definite uses.
So to add code completion or auto-completion for pseudo properties/methods you would put PHPDoc syntax.
/**
* Someclass class
* @property [Type] [name] [<description>]
* @method [return type] [name]([[type] [parameter]<, ...>]) [<description>]
*
*/
class Someclass {}