Service  level  agreements  (SLAs)  constitute  some  of  the most  important instruments  for representing and managing     IT-centric     services     performance and value. However,  achieving  realistic  and  effective  SLAs  can   be   elusive.   The   problem   is   relatively   under-researched and normative descriptions of what should be represented, monitored and measured in SLAs tend not to correspond with key events that unfold during the course of the  production  of  services  over  time.  We  argue  that designing  SLAs,  or  related  instruments,  that  accurately and  usefully  reflect  services  as  they  are  enacted  can  be served  by  a  deeper understanding  of  the  practice  of  IT-centric  services.  Based  on  an ethnographic  study  of interactions  between  a  large  global  IT-centric  services provider  and  a  global  financial  services  company,  this paper  presents  an  approach  to  researching  the  problem and   some   preliminary   results which   document   and analyse dimensions  of  the  service  engagement  that  are under-represented   in   formal representations   but   are value-enabling.  The  study  is  framed  using  the  relational theory of contract (Macneil 1980).