Root cause (instrumented, DECISIONS 2026-05-30): a DB recipe dumps its data in a backupbot pre-hook,
but if the DB container cycles mid-dump (intermittent on the loaded CI node — full5/6/7 RED, full8
green; NOT OOM/NOT healthcheck) the dump is truncated/absent and restic snapshots an empty path —
abra app backup 'succeeds' yet a later restore silently loses the data (ghost ci_marker).
Fix (additive, recipe-scoped via meta like READY_PROBE): recipe_meta may define BACKUP_VERIFY(domain)
-> bool, a READ-ONLY post-backup integrity probe. When it returns False the harness re-runs the whole
backup (fresh snapshot, re-stabilised db) up to 3x. Recipes without the hook are unaffected. ghost's
BACKUP_VERIFY confirms /var/lib/mysql/backup.sql.gz is a valid non-empty gzip. Weakens no assertion —
it only retries a flaky CAPTURE so P4 restore is RELIABLY exercised, not luck-dependent.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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