# Loop prevention keys on (origin device ID, sequence), not content hash

The original protocol draft used `content_hash` recent-history dedup as the
loop breaker. That is wrong for many-to-many: two different devices pasting
the same text are falsely dropped as echoes, and the hash is optional so the
gate is bypassable. The loop breaker is now the immutable origin device ID plus
a per-peer monotonic sequence: ignore updates whose `(origin, sequence)` is not
newer than the last-seen pair, and drop any update whose origin is the local
device. `content_hash` is retained only for integrity/diagnostics.