Yes there is, but XP’s “activities” are not formally identified or described. you’ll find it headed “Define requirements with stories, written on cards” and then throughout the chapter is a mixture of process description and guidance about what use stories are and how (and by whom) they should be produced. And so it goes on, as the books describe XP under major headings; “things done” and “things produced” are described with varying degrees of prescription and detail. RUP’s apparent prescription comes from its completeness and greater formality in its systematic treatment of activities, and their inputs and outputs. XP does not lack prescription, but perhaps in the attempt to remain “lightweight”, the formality and detail are simply omitted. The detail that is present in RUP will have to be added when XP is implemented on a project. Lack of specificity is not a strength or a weakness, but you should not confuse the lack of detailed information in XP with simplicity. At some point, the people on the project will need to know what to do and at that time will need the detail.