The sync sweep and the storage sweep ran in disjoint PRNG streams off the same seed and never intersected: no exchange ever ran over a client store that could tear. A partial pull could leave torn frames that recovery accepts but a resumed session never converges past.

runCrashResume backs the client store with a real LogStore over a tearable FaultyFile instead of the pure MemStore, seeded healthy then armed to tear. Between phase-1 rounds, on a seeded coin, it power-cuts the store mid-persist, reopens it, reloads the recovered prefix, and resumes with a fresh Client over the same durable store, mirroring cmd/sync's loadContentStore for wire-name to log-digest identity.

The oracle keeps every existing sync invariant and adds the crash bite: post-recovery contents are a subset of the pre-crash held set, no corrupt frame crosses the boundary, and phase-2 liveness heals both domains before a fresh session converges in the bounded window (sync 3.7). One seeded PRNG stream drives the whole run, so a failure replays from the shared reproduce line.

The composed-fault and liveness-under-faults discipline follows TigerBeetle's VOPR. closed check-in: d2b5f729ef user: dmestas tags: h3-crashsync