Evolution of software architectures is, different from architectural design, an area that only few tools have covered. We claim this is due to the lack of support for an important concept of architectural evolution: the notion of architectural design decisions. The absence of this concept in architectural evolution leads to several problems. In order to address these problems, we present a set of requirements that tools should support for architectural evolution. We evaluate existing software architecture tools against these architectural requirements. The results are analyzed and an outline for future research directions for architectural evolution tool support is presented.