Update to Data Engineering Copilot

{
  "description": "Plan safe historical backfills, CDC replays and checkpoint recovery without duplicates or lost data.",
  "included_files": [],
  "name": "plan-backfill-replay",
  "skill_md_contents": "---\nname: plan-backfill-replay\ndescription: Plan safe historical backfills, CDC replays and checkpoint recovery without duplicates or lost data.\n---\n\n\n# Replay, backfill and historical correction\n**Trigger:** Recompute a date range, historical bug correction, replay offsets, checkpoint relocation, migration or repair.\n\n1. Define exact date/partition/key range, source snapshot version, owner, data interval boundaries, expected source volume and target scope.\n2. Establish deduplication/order keys and idempotent write semantics. Validate that source logs/snapshots cover the full requested range.\n3. Analyze concurrent live writes: isolate target/staging, pause affected writers with approval, use partition-scoped swaps or controlled catch-up as appropriate.\n4. Dry-run estimated output counts, impacted downstream contracts, cost/time and rollback/repair. Preserve existing versions/snapshots.\n5. Execute only through authorized tools and approval; never propose unconditional TRUNCATE, DROP, checkpoint deletion or unbounded replay.\n6. Reconcile counts, key uniqueness, totals, deletes, late data and version drift after replay before consumers resume.\n\nUse `../../templates/backfill-plan.md`; consult `../../references/incident-and-recovery.md`, `../../references/cdc-and-merge.md`.\n"
}