Designing mobile and wearable applications is a challenge. The context of use is more important than ever and traditional methodologies for elicitation and specification reach their limits. This paper investigates the challenge of creating and communicating information about the user's primary task with regards to its fine grained temporal structure. TaskObserver is a TabletPC software that allows real-time logging of events during observations of complex mobile scenarios. The results are communicated to other team members using task trace graphs of the events observed. Keywords observations, field coding, multi modality, wearable computing, mobile computing, context of use ACM Classification Keywords H5.2. User Interfaces: Theory and Methods.