The development of a distributed application that exhibits both desired functionality as well as performance is a complex task. Therefore the construction of monitoring tools to assist in the development of complex distributed applications is of great practical significance. Monitoring tools can be used to observe the behavior and fine tune the performance of an application. One of the fundamental problems that must be addressed in order to construct an effective monitoring tool is to ensure that the tool is able to report the true behavior of an application, that is, it is able to monitor the application non-intrusively. In order to do so we must avoid the affects of monitoring on the outcomes of non-deterministic aspects of a computation, including non-determinism introduced explicitly by the application programmer and non-determinism in the scheduling of application processes. We present protocols that enable the preservation of the overall program behavior.