Qwixl Agent-to-agent protocols assume a live HTTP or streaming hop. Many deployments cannot keep every agent always reachable: devices sleep, cost tiers duty-cycle backends, and operators park agents outside business hours. Senders need a machine-readable asleep signal, a bounded expectation for store-and-forward, and validation rules so an offline agent is not a spam sink and does not act on forged or expired messages after wake. This document profiles offline delivery and reachability for A2A- style JSON-RPC messaging. It defines abstract reachability modes, an asleep refusal signal, queue bounds and distinct queue-full errors, validate-on-dequeue requirements, and split delivery semantics (durable persist versus notify). It is independent of Messaging Layer Security (MLS) grouping; deployments that also use [GOMLS] MAY apply both profiles.