Rein Application Security Platform is an agentless visibility solution that provides real-time context for application security across development, staging, and production environments. The platform monitors user interactions, resource access, API invocations, and code execution without using sampling, proxies, sidecars, or eBPF technology. The platform offers visibility into AI applications, MCPs (Model Context Protocol), and AI agents, tracking who accessed them and when. It provides API discovery and protection by mapping endpoints in real time without scanning or sampling. For software composition analysis, it identifies which libraries actually execute rather than just being loaded into memory, and determines which CVEs pose actual risks. The platform includes detection and response capabilities with full trace functionality across endpoints and functions. It provides forensic investigation features that create incident timelines showing what executed, when, and by whom. The system enforces automatic guardrails across functions and libraries with zero mean time to remediation. The technology operates as a read-only layer that does not modify applications or runtimes. It reports performance impact of 0.1% CPU usage, 20MB memory consumption, and 400 microseconds per request. The platform does not use agents, hooks, instrumentation, or runtime modification.