  Software intensive systems play a crucial role in most, if not all, aspects
of modern society. As such, both their sustainability and their role in
supporting sustainable processes, must be realized by design. To this aim, the
architecture of software intensive systems should be designed to support
sustainability goals; and measured to understand how effectively they do so. In
this paper, we present the Sustainability Assessment Framework (SAF) Toolkit --
a set of instruments that support architects and design decision makers in
modeling sustainability as a software quality property. The SAF Toolkit is the
result of our experience gained in over a decade of cases in collaboration with
industrial partners. We illustrate the toolkit with examples stemming from
various cases. We extract our lessons learned, and our current research and
future plans to extend the SAF Toolkit for further architecture modeling and
measurement.
