A Blocked Agent Is a Captive Client

Long-running agents discover mid-task that they need a destination their egress proxy does not allow, and the block comes back as an opaque connection failure with no machine-actionable way to ask for access and no human standing by. That block is a requestable denial, and the egress proxy is a policy enforcement point. RFC 8908, the Captive Portal API, supplies the recovery state machine for a…