Cloudflare has introduced Precursor, a client session-level verification system designed to distinguish between human and automated traffic. By dynamically injecting lightweight JavaScript into web pages, Precursor continuously collects behavioral signals such as pointer movements, keyboard rhythms, and focus visibility. These signals are evaluated in real-time at edge nodes to differentiate human traffic from automated or agentic traffic. Precursor extends single challenges into comprehensive session analyses, integrating with Turnstile and existing Bot Management systems to adjust bot scores based on session data, identifying long-term anomalies, session fraud, and automation behaviors. Cloudflare assures that only minimal necessary information is collected, such as keyboard rhythms without specific content, and signals are used solely for internal risk control without exposure to client accounts or long-term profiling. Precursor is now available on enterprise user dashboards, configurable between low-friction observation and strict verification modes.