Systematic approaches like the family of Action Description Languages have been designed for the formal assessments of action calculi. We assess the fluent calculus for knowledge and sensing with the help of the recently developed, high-level action language Ak. As the main result, we present a provably correct embedding of this language into fluent calculus. As a spinoff, the action programming language FLUX, which is based on fluent calculus, provides a system for answering queries to Ak domains. Conversely, the action description language may serve as a high-level surface language for specifying action domains in FLUX.