Comprehensive AI services (CAIS) is an approach to understanding superintelligence proposed by Eric Drexler. In Drexler's words, "CAIS provides a model of flexible, general intelligence in which agents are a class of service-providing products, rather than a natural or necessary engine of progress in themselves."[1] On this approach, advanced AI systems are conceived as "services", or systems with an expanding set of capabilities, one of which is the optional capability of agency.