This thesis introduces a framework for decision support during the design of applications for the cloud, or migration of existing applications to a cloud environment. For this purpose, a GENeralized Topology Language (GENTL) is introduced and mappings from existing languages to GENTL are provided. An annotation scheme for GENTL, which can capture annotations to topologies and topology elements is designed and instantiations for different annotation types are given. A framework implementing import functionalities for the topology languages Blueprint and TOSCA is presented. The framework enables the annotation of topologies with documentation annotations, references to external resources and incorporates a series of annotations which can be used to retrieve cost calculations from the external decision support system Nefolog.