Summary
Cloudflare added Precursor, a client-side JavaScript that continuously evaluates behavioral signals across a session and updates bot scores in real time, feeding re-validation into existing bot protections.
What changed
On 2026-07-13 Cloudflare shipped Precursor session-based bot detection: client-side JS that evaluates behavioral signals continuously across a session, re-validates, and updates bot scores integrated with existing Challenges protections.
Why it matters
Static, request-time bot checks are increasingly evaded by sophisticated automation and AI agents. Continuous, session-long behavioral scoring catches bots that pass an initial challenge but behave anomalously later, tightening the trust boundary as automated traffic grows.
Evidence excerpt
Precursor introduces session-based bot detection: client-side JavaScript enabling continuous behavioral signal evaluation across sessions, with re-validation and bot score updates.