Researchers in the life-sciences are currently limited to small-scale informatics experiments and analyses because of the lack of interoperability among life-sciences web services. This limitation can be addressed by annotating services and their interfaces with semantic information, so that interoperability problems can be reasoned about programmatically. The Moby semantic web framework is a popular and mature platform that is used for this purpose. However, the number of services that are available to select from when building a workflow is becoming unmanageable for users. As such, attempts have been made to assist with service selection and composition. These tasks fall under the general label of automated service composition. We present a prototype workflow assembly client that reduces the number of choices that users have to make by (1) restricting the overall set of services presented to them and (2) ranking services so that the the most desirable ones are presented first. We demonstrate via an evaluation of this prototype that a unification of relatively simple techniques can rank desirable services highly while maintaining interactive response times.