The good news survives checking. An APNs auth key belongs to the developer account, not a machine, and
a device token belongs to the app, not a server — so N installs holding the same .p8 all push to one
phone with no coordination, and the app posting its token per server is something the multi-server
manager does anyway.
One field is missing: the payload carries no origin. That breaks the deep link (a session id is
meaningful only on the server that issued it), and threading, and — least obviously and most
expensively — `mv`. That is a content hash of THAT server's catalogue, and the client's rule is
`mv !== version → resync`. One stored catalogue and five servers means every push from B invalidates
what was synced from A, forever. It would present as a battery and data problem rather than a bug.
Where the identifier comes from is deliberately left to the sign-on design: the multi-server manager
already needs a key per server, and notifications should adopt it rather than invent a second identity
that drifts the first time a host is renamed.
Records what stays per server on purpose — devices, per-chat mute preferences, the catalogue itself —
because the app is what joins them, which is the same shape as the sign-on work.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
