be developed, the top-down approach emphasises to start
with abstract descriptions that should be refined incrementally
until we achieve the detail level necessary to implement it.
Unfortunately, there exist a semantic gap in interaction protocol
methodologies because most of them first, identify which tasks has
to be performed, and then use low level description such as
sequences of messages to detail them.
In this paper, we propose an approach to bridge this gap proposing a set of techniques that are integrated in a methodology called MaCMAS (Methodology for Analysing Complex Multiagent Systems). We model MAS protocols using several
abstract views of the tasks to be performed, and provide a
systematic method to reach message sequences descriptions from
task descriptions. These tasks are represented by means of
interactions that shall be refined systematically into
lower-level interactions with the techniques proposed in this
paper (simpler interactions are easier to describe and implement
using message passing.) Unfortunately, deadlocks may appear due to
protocol design mistakes or due to the refinement process that we
present. Thus, we also propose an algorithm to ensure that
protocols are deadlock free.