As part of CERN's Next Generation Triggers (NGT) project, the R³ (Real-time Reconstruction Revolution) program aims to rethink how the High-Level Trigger (HLT) event reconstruction is performed within the CMS Collaboration. A key objective of R³ is to ensure an accurate and robust reconstruction, validating the quality of physics objects measured during data-taking at the upcoming High-Luminosity LHC. This contribution presents our latest efforts to develop robust validation tools for the HLT community in CMS, as new, untested, and heterogeneous algorithms are rapidly developed and deployed. We detail the tools and observables defined and measured for jets, missing transverse energy (MET and MHT), and Particle Flow objects, which are essential for comparing detector configurations across different phase-space regions. We outline the metrics established to validate all objects, including efficiencies, fake rates, responses, and resolutions. Furthermore, we demonstrate how these tools have already improved the reconstruction of certain objects, fostering collaboration with relevant experts. Finally, we highlight the potential for these tools to also benefit the offline reconstruction, given some similarities with the HLT.