stream_subscribe_worker_exits_total{reason} + a warn log on read-batch and write errors. found 2026-08-13: relay-eval connections died with ReadFailed during delete-compaction passes (6 of 7 coverage dips in 26h) and stream recorded nothing — the delivery loop's error paths were silent 'catch return's. prime suspect is the 5s wedged-writer kill (upstream's frameWriteTimeout, faithfully ported) firing during compaction I/O stalls; this family plus the log line turns the next pass into labeled evidence. upstream has no equivalent metric — recorded as a stream-only addition in docs/upstream-subscribe-protocol.md. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>