  Repairing legacy systems is a difficult and error-prone task: often, limited
knowledge of the intricacies of these systems could make an attempted repair
result in new errors. Consequently, it is desirable to repair such systems in
an automated and sound way. Here, we discuss our ongoing work on the automated
repair of scenario-based models: fully executable models that describe a system
using scenario objects that model its individual behaviors. We show how rich,
scenario-based models can be model-checked, and then repaired to prevent
various safety violations. The actual repair is performed by adding new
scenario objects to the model, and without altering existing ones - in a way
that is well aligned with the principles of scenario-based modeling. In order
to automate our repair approach, we leverage off-the-shelf SMT solvers. We
describe the main principles of our approach, and discuss our plans for future
work.
