Now I’m tempted to write a NIP…

“AI is a horse” is reasonably accurate, very humorous, and Haiku-like in its brevity. https://kconner.com/2024/08/02/ai-is-a-horse.html (via Hacker News)

Is that “outbox model” specified in a NIP?

True, but that is a separate issue and there are various mechanisms that can be used to verify that a single recent note was received.

On Nostr, for a public key that I subscribe to, how can I verify that my relays aren’t filtering out messages from that key? Is there a merkle hash on your latest note that I can use to verify that your previous notes were all received?