Using InDesign Server,
I need to check each all stories avaiable. if there are a overset in a textframe, I need to return all tags associated to this story.
how can I find out all tags related to a stories?
As you don't mention how you "talk" with IndesignServer i' ll put it in general: Stories are direct children of the document object. If you iterate thru all stories you can check immediately on "overset" or "overflow".
This is not typical IndesignServer stuff. It's really mandatory to understand Indesigns object tree in order to do something usefull. There are various tutorials and fora provided by Adobe, depending on the method you want to use.
Hope this helps!