backlog(B-0591): wire tick-shard schema validator to CI (B-0529 Later item)

docs/backlog/P3/B-0591-wire-shard-schema-validator-to-ci-2026-05-17.md

@@ -0,0 +1,67 @@
+---
+id: B-0591
+priority: P3
+status: open
+title: Wire tick-shard schema validator into gate.yml (non-required → required)
+created: 2026-05-17
+last_updated: 2026-05-17
+depends_on: [B-0529]
+parent: B-0529
+type: factory-hygiene
+decomposition: atomic
+---
+
+# B-0591 — Wire tick-shard schema validator into gate.yml
+
+**Priority:** P3 (non-blocking — validator is advisory until shards are compliant).
+**Filed:** 2026-05-17.
+**Filed by:** Otto-CLI.
+**Effort:** S (single workflow edit + sweep cycle).
+**Parent:** [B-0529](../P2/B-0529-tick-shard-schema-validator-vs-practice-drift-2026-05-15.md) Recommendation "Later" item.
+
+## What
+
+`tools/hygiene/check-tick-history-shard-schema.ts` validates that every tick shard's first non-empty line is a 6-column pipe-row matching the path/filename timestamp. Today the validator exists but is NOT wired into any CI workflow (`grep -rn "check-tick-history-shard-schema" .github/workflows/` returns 0 matches).
+
+Per B-0529's Recommendation:
+
+> **Later** (separate row): wire the validator into CI's `gate.yml` as a non-required check first, promote to required after a sweep cycle.
+
+This row tracks that work.
+
+## Why this matters
+
+The B-0529 cycle landed two pieces of substrate on main today (2026-05-17):
+
+- [PR #3990](https://github.com/Lucent-Financial-Group/Zeta/pull/3990) — `tools/hygiene/add-pipe-row-header.ts` (the retrofit tool + 28 unit tests)
+- [PR #4004](https://github.com/Lucent-Financial-Group/Zeta/pull/4004) — README hybrid-pattern endorsement
+
+What is STILL missing: a CI gate that catches new shards that don't follow the schema. Without it, future shards can re-introduce the drift (the same failure mode that produced 359 violations in the first place — well-intentioned authors writing H1-first without realizing the schema validator existed).
+
+## Acceptance
+
+- [ ] **Slice 1 (this row, P3): wire validator as non-required check** in `.github/workflows/gate.yml`. Job runs on every PR that touches `docs/hygiene-history/ticks/**.md`. Non-required means CI surfaces the violation but does not block merge. Provides observability without enforcement.
+- [ ] **Slice 2 (separate row, after Slice 1 + bulk-retrofit lands): promote to required check**. Pre-requisite: 0 existing violations on `main` (so the required check passes on every PR touching shards). Bulk retrofit (running `tools/hygiene/add-pipe-row-header.ts --write` on all 359 non-compliant shards) is the precondition.
+
+## Why P3, not P2
+
+The drift is non-blocking today (validator unwired). The reverse-drift risk (new shards re-introducing violations) is real but slow — the operational cost is "a few new violations per week until detected." Filing as P3 because:
+
+- P0/P1 reserved for blocking issues
+- P2 reserved for clear value-multiplier substrate (B-0529 itself was P2 because it's the parent row covering the whole drift)
+- This row is the gate-wiring slice — meaningful but not urgent
+
+If reviewer triage promotes to P2 that's fine.
+
+## Composes with
+
+- [`docs/backlog/P2/B-0529-tick-shard-schema-validator-vs-practice-drift-2026-05-15.md`](../P2/B-0529-tick-shard-schema-validator-vs-practice-drift-2026-05-15.md) (parent)
+- [`tools/hygiene/check-tick-history-shard-schema.ts`](../../../tools/hygiene/check-tick-history-shard-schema.ts) (the validator to wire)
+- [`tools/hygiene/add-pipe-row-header.ts`](../../../tools/hygiene/add-pipe-row-header.ts) (the retrofit tool; bulk-run is precondition for Slice 2)
+- [`.github/workflows/gate.yml`](../../../.github/workflows/gate.yml) (target workflow)
+- [`docs/hygiene-history/ticks/README.md`](../../hygiene-history/ticks/README.md) (schema docs; updated in PR #4004)
+
+## Not in scope
+
+- The bulk-retrofit `--write` run across all 359 non-compliant shards. That is the precondition for Slice 2 (promote-to-required) but should be its OWN row (huge PR; separate review cost). Candidate name: `B-NNNN-shard-pipe-row-bulk-retrofit-run-2026-05-17.md`.
+- Migrating pre-2026-04-29 legacy single-row-format shards. Per B-0529: those stay in legacy format as historical record.