We present all aspects of the development of a ½U laser guide star CubeSat payload. The payload, AMS Beacon, was integrated into the Agile Microsat (AMS) 6U platform developed by MIT Lincoln Laboratory and will function as a space-based point source reference for high-angle-rate adaptive optics (AO) control. In addition to a 500-mW onboard laser, it carries a retro-reflector and a photodiode (PD) with a 1 kHz readout. The system, launched successfully in May 2022 into low-Earth orbit, utilizes commercial components, fixed optics, and high-precision body-pointing enabled by a bus-provided GPS receiver, among other innovations, to keep the design compact and the costs low. To our knowledge, it is the first payload to be built as a test platform for high-angle-rate AO on orbital targets. The system architecture offers opportunities for future cost reductions and a strong foundation for payload proliferation across multiple satellites. The capabilities of the host spacecraft combined with the Beacon payload can also serve as a roadmap for integrating thrusting capabilities with an artificial guidestar, which would be critical in enabling various astronomical applications.