Files
amethyst/commons
Claude 9b8729db22 feat(marmot): push token gossip in the shape the spec adopted
Kind 451 had no callers, and the reason turned out to be everything around
it: the 447/448/449 events in this tree were the exploratory shape the spec
now names as not interoperable — tokens in `token` tags with empty content,
the sender's leaf implicit, no removals at all, and no owner authentication.
The token encryption derived its key from the old `mip05-v1` salt, and the
446 trigger still carried the `encoding` tag the adopted rumor dropped.
Wiring the proof into that would have produced records no peer can read.

So the gossip is now content-JSON under `marmot-push-v1`, and the version
string is the gate: the old value is refused rather than translated, because
the two versions are not predecessor and successor.

The design the rewrite is really about is owner authentication. A record's
authority comes from its own `owner_sig` and current membership, never from
who carried it — which is what lets one member relay another's records so a
group converges without every owner being online, while stopping the relayer
from repointing, re-signing or restamping what it carries. `PushSignedRecord`
is the canonical byte string that makes both halves computable; it uses the
spec's fixed-width fields rather than this codebase's usual QUIC varints,
which look identical locally and are wrong on the wire.

The part that costs real machinery is revocation. A removal does not merely
delete: it leaves a tombstone at its own `(owner_ts, digest)` stamp, and that
stamp has to be durable. Any current member can re-emit a revoked but still
validly-signed record in a fresh kind 448 at any later epoch, so its carrying
epoch is unbounded and no retained-message window can bound it. The stored
stamp is the only thing that recognises such a record as stale, which is why
`MarmotPushStateStore` exists and why Amethyst backs it with a file.

Everything here is advisory end to end. A bad entry, an unverifiable
signature, a stale list — each drops on its own and none of it may reach the
validity of the kind:445 that carried it. The decoders return what they could
read instead of throwing, and the coordinator catches at its boundary, so a
surprise cannot escape into ingest.

Not wired: announcing a token of our own. That needs Amethyst's own
notification-server public key, which is a deployment decision rather than
something the protocol discovers — a server can only wake the app whose push
credentials it holds. Until it exists this client participates correctly in
other members' routing and announces nothing.

MDK's `wn` exposes no push commands, so the harness cannot drive this against
the reference. Coverage is the spec's published removal fixture, byte-layout
assertions written independently of the encoder, and the ordering and
tombstone rules.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016kCuA6tc4JQzHPCDd39GHq
2026-09-09 20:00:35 +00:00
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