diff --git a/docs/hygiene-history/ticks/2026/04/29/0634Z.md b/docs/hygiene-history/ticks/2026/04/29/0634Z.md
new file mode 100644
index 000000000..25daf6d37
--- /dev/null
+++ b/docs/hygiene-history/ticks/2026/04/29/0634Z.md
@@ -0,0 +1 @@
+| 2026-04-29T06:34:56Z | claude-opus-4-7 | 26f978a2 | speculative-audit + thread-triage tick. (1) Backpressure check per B-0100/B-0103: queue depth = 3 (#811, #815, #816), all in CI. Per the rule, would have skipped pure-wait shard creation — but substantive event materialized: PR #815 had 1 unresolved Codex thread on cross-PR reference. (2) Local markdownlint of all 4 PR #815 files (research note + 3 backlog rows) — clean, no drift to catch ahead of CI. (3) PR #815 thread classification: REVIEWER_SNAPSHOT_LAG (cross-PR reference variant) — the cited sibling absorb file lives on PR #811's branch (currently in CI). Once #811 merges, the reference becomes valid. Posted classification comment + resolved thread. | [#815 cross-PR-ref thread resolved](https://github.com/Lucent-Financial-Group/Zeta/pull/815), [#811 + #816 still in CI](https://github.com/Lucent-Financial-Group/Zeta/pull/811) | First operational application of the backpressure rule (B-0100/B-0103): the rule said "queue ≥ 3 + no substantive event + only CI pending = skip shard." Two of three conditions held; the third (no substantive event) flipped when investigating #815 produced a classifiable thread. The rule worked: it forced me to verify substantive-event-presence before creating a shard, which surfaced the speculative-lint-as-pre-CI-defense pattern. New micro-class observation: **cross-PR-reference / sibling-absorb-ordered-merge-dependency** — when one PR references files added by a sibling PR, the reference is valid post-merge but Codex/Copilot evaluating against current main flag it as broken. Resolution: classify as REVIEWER_SNAPSHOT_LAG with explicit ordered-merge-dependency note; will become real defect only if sibling PR fails to land. |