The Mitegen Sentinel Watchdog Kit G2 GAGG is a dynamic X-ray beam stop with a built-in detector that provides real-time X-ray beam monitoring and dosing information. The kit allows for continuous monitoring of beamline stability and helps determine the exact sample radiation dose exposure without interfering with diffraction data collection. The micro-sized design minimizes shadowing of the diffraction pattern, ensuring accurate results. This kit includes two GAGG beam stops with embedded single-piece GAGG(Ce) crystals and fiber-optic cable attachments, a diode cable assembly to connect the fiber optic cable, and an autoranging picoammeter that amplifies the diode output and provides the signal to a PC via USB cable. Developed in collaboration with the Lawrence Berkeley National Lab, the Mitegen Sentinel is an essential tool for setting up and calibrating beamlines or home sources.