In today's global and highly competitive business environments, organisations are replying to the question of whether technology is forming business or vice-versa by integrating their business and IT strategies, thus using technology to do business. As a consequence, there is an increasing pressure for building software systems that are able to cope with new requirements imposed by both technological advances and different business rules. At the same time, it is now widely accepted that, although Object-Oriented techniques have provided useful tools for software construction, their support cannot be extended directly to evolution. Even worse, it is becoming evident that there is a lack of theoretical principles and accompanying practical tools that can effectively support software evolution. In this paper, we describe in detail a development tool that is based on sound mathematical principles and supports an architecture-based approach to evolution centred on the notion of coordination contract--a modelling primitive that treats components as black boxes and is compositional with respect to change.