Policy coverage is the set of rules that determines which web destinations, user actions, and device types are sent through remote browser isolation or similar containment controls. In practice, it defines whether a site opens in the local browser or in a remote session, and whether actions such as downloads, copy and paste, printing, or file upload are allowed, blocked, or rewritten.
This matters because browser isolation only reduces risk if the right traffic is actually covered. If phishing pages, unknown domains, or unmanaged devices fall outside the policy, attackers may still reach the endpoint directly. Strong coverage helps defenders contain drive-by malware, malicious links, and browser exploits while keeping business access usable. Security teams often tune policy coverage by user group, site category, risk score, and device posture so high-risk activity is isolated by default.