We present a first approach that combines the mobile agent and the compositional paradigms into a new agent-based compositional model. The aim of this work is to explore the capabilities of both paradigms in improving the design and development of open and distributed systems. Our goal is to add compositional characteristics to mobile agents by defining an agent-based compositional model. We take advantage of the mobility and the composition capability by applying this model to the problem of searching software components in partially-instantiated applications, both in design and run time. That is, the abstract components of an architectural design of an application can be fulfilled with concrete ones by retrieving them from the Internet.