Equal sequence numbers are not enough to delete a block.Compare complete logical events, references, physical encoding, and post-repair invariants on an evidence copy.

Three boundaries need separate proof.

Writer ownership

One in-process chain does not exclude a second process.

Durable cursor

Append can become durable before live memory records acknowledgement.

Batch identity

Sequence alone cannot prove a retry is the same operation.

Scanner

The committed-region refusal is the final defense, not the root cause.

Choose the least destructive outcome.

Defaultquarantine + continue

Preserve the original and move reviewed context to a fresh Session.

Evidenceread-only extraction

Report the valid prefix and duplicate candidate without claiming resumability.

Exceptionalversion-aware repair

Stage a new artifact only after unique exact-duplicate proof and full replay.

Never renumber the log.

Sequence, source references, replacements, tool lifecycle, and request evidence still describe the original history.

Primary evidence.

Repair identity, not just numbering.

The complete runbook includes evidence freezing, mismatch routing, exact-duplicate proof, recovery choices, a durable compare-and-append contract, regression matrix, and fifteen acceptance gates.

Read the complete runbook