Summary
On August 7, 2026 Cloudflare introduced Precursor, a privacy-minded, client-side verification system that injects JavaScript to continuously collect behavioral signals during a session and detect subtly inhuman bot and agent traffic that network signals alone miss.
What changed
August 7, 2026: Precursor is a client-side, session-based verification system that uses dynamically injected JavaScript to continuously collect behavioral signals as visitors interact with an application, catching subtly inhuman bot traffic that can evade network-signal analysis. It pairs with BotBase, a directory that tracks both good and less-than-good bots and agents.
Why it matters
As agents increasingly browse and act on the web, static bot detection breaks down because behavior shifts between human and agentic mid-session; continuous client-side scoring lets site owners allow wanted agents and block extractive ones without breaking real user flows.
Evidence excerpt
Precursor is a continuous client-side system to detect even subtly inhuman bot traffic that can fly under the radar when assessing network signals alone.