How does Cloudflare determine when to issue a Managed Challenge to a visitor?

Cloudflare's Managed Challenge system uses a combination of signals to determine if a request warrants a challenge. These signals include, but are not limited to, threat intelligence from Cloudflare's vast network, known bot signatures, behavioral analysis, IP reputation, HTTP header anomalies, and browser characteristics. Machine learning models continuously analyze these signals to assess the likelihood that a request originates from a malicious bot. If the risk score for a request crosses a certain threshold, a Managed Challenge is dynamically issued to verify the legitimacy of the client, without necessarily interrupting the browsing experience of a human user.