BluSapphire OneAgent is an endpoint detection and response solution that uses a prevention-first approach to stop threats before execution. The agent operates with a response time under 20 milliseconds to prevent zero-day attacks, ransomware, and fileless malware at the pre-execution stage. The solution provides cross-platform protection for Windows endpoints, Linux servers, and containerized workloads through a single agent. It maintains a memory footprint of approximately 100KB and uses less than 1% CPU during operation. OneAgent uses a patented behavior design system that does not require signature updates or constant maintenance. The agent can operate in air-gapped and offline environments without requiring cloud connectivity for protection decisions. The solution can be deployed as a standalone endpoint protection platform or alongside existing security tools such as Windows Defender without conflicts. It provides prevention, detection, and response capabilities across supported platforms. The agent makes local security decisions without requiring external connectivity, enabling deployment on mission-critical systems and in environments with limited network access. The architecture is designed to minimize false positives and reduce operational burden on security teams.