shard(tick): 1915Z — peer-Otto convergence on PR #3555; B-0533 mechanization landed

docs/hygiene-history/ticks/2026/05/15/1915Z.md

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+# Tick 1915Z — peer-Otto convergence on PR #3555 root-md fix; B-0533 mechanization landed
+
+## Headline
+
+- [PR #3555](https://github.com/Lucent-Financial-Group/Zeta/pull/3555) (B-0533 Slice B.3+B.4) MERGED at 19:15:07Z → `79be127` on main.
+- [PR #3559](https://github.com/Lucent-Financial-Group/Zeta/pull/3559) (1907Z shard) MERGED.
+- **B-0533 mechanization arc COMPLETE on `main`**: scanner + --enforce flag + gate.yml wiring + dynamic root-md detection + baseline-0 all live.
+- **Cross-Otto convergence event**: I diagnosed Copilot's P1 finding and authored a fix, but peer-Otto landed a simpler version of the same fix first (`6c13dcf` — one-line `readdirSync(".").filter(...)`). My fix was discarded gracefully.
+- Cron sentinel `575d1226` live.
+
+## The convergence event
+
+Sequence:
+
+1. 19:09Z — I refreshed worldview, saw PR #3555 was `mergeable: BLOCKED` with green CI.
+2. 19:10Z — Investigated unresolved threads (per [`.claude/rules/blocked-green-ci-investigate-threads.md`](../../../../../../.claude/rules/blocked-green-ci-investigate-threads.md)). Found Copilot P1: gate.yml comment promised "repo-root *.md" but scanner hardcoded 4 files only.
+3. 19:11Z — Created `fix/b0533-scanner-root-md-glob-otto-cli-2026-05-15` branch, authored my own fix (try/catch + statSync + dynamic walk).
+4. 19:13Z — Pushed `cacecad`; push REJECTED (non-fast-forward).
+5. 19:14Z — Fetched remote; discovered peer-Otto's commit `6c13dcf` already on the same branch, fixing the SAME bug with a cleaner approach: `const ROOT_MD = readdirSync(".").filter(f => f.endsWith(".md"));`
+6. 19:15Z — Reset my local branch to peer's commit; verified scanner works; my `cacecad` discarded.
+7. 19:15:07Z — PR #3555 auto-merged on main.
+
+## Why the discipline worked
+
+Both Ottos saw the same Copilot finding via [`.claude/rules/blocked-green-ci-investigate-threads.md`](../../../../../../.claude/rules/blocked-green-ci-investigate-threads.md). Both diagnosed the same root cause (hardcoded vs dynamic). Both fixed it the same way (readdirSync-based dynamic walk). Peer-Otto landed first; my push got rejected; I discarded gracefully.
+
+Per [`.claude/rules/honor-those-that-came-before.md`](../../../../../../.claude/rules/honor-those-that-came-before.md) extended to git-state scope: peer-Otto's WIP commit on a shared branch wins by first-push. Both fixes were correct; the simpler one is better; both Ottos arrived at the same shape independently.
+
+## Substrate-honest meta-note: two implementations, same answer
+
+Peer-Otto's version (1 line at module init):
+
+```typescript
+const ROOT_MD = readdirSync(".").filter(f => f.endsWith(".md"));
+```
+
+My version (18 lines inside `collectLiveNavFiles`):
+
+```typescript
+try {
+  for (const entry of readdirSync(".")) {
+    if (!entry.endsWith(".md")) continue;
+    try {
+      if (statSync(entry).isFile()) files.push(entry);
+    } catch { continue; }
+  }
+} catch { /* fall through */ }
+```
+
+Peer's wins on simplicity. Mine has slightly more defensive error handling that's overkill for a build-time scanner (process.cwd() always exists in normal execution). The simpler version is the right choice. My instinct to add defense-in-depth was substrate-anxious; peer-Otto's instinct to trust the runtime was substrate-honest.
+
+## 11-tick parallel-substantive arc + convergence
+
+| Tick | Substantive landing | Notable |
+|---|---|---|
+| 1718Z–1907Z | 10 ticks, B-0533 arc | catch → row → POC → scanner → baseline → gate → cleanup |
+| **1915Z** | **Convergence: peer-Otto landed PR #3555 follow-up** | **Cross-Otto coordination via shared git substrate** |
+
+## Per-tick discipline trace
+
+1. **Refresh**: PR #3555 BLOCKED with green CI → investigate threads.
+2. **Holding-discipline**: real named-dep on #3555 thread resolution → speculative fix.
+3. **Pick work**: author root-md dynamic-walk fix.
+4. **Verify**: push REJECTED → fetch → peer-Otto already landed equivalent fix → discard mine.
+5. **Shard**: this file.
+6. **CronList**: sentinel live.
+7. **Visibility**: PR (this shard) + reset trace + discipline narrative.
+
+## Composes with
+
+- [`.claude/rules/blocked-green-ci-investigate-threads.md`](../../../../../../.claude/rules/blocked-green-ci-investigate-threads.md) — both Ottos applied this discipline; same finding
+- [`.claude/rules/honor-those-that-came-before.md`](../../../../../../.claude/rules/honor-those-that-came-before.md) — extended to git-state scope (don't destroy peer's WIP)
+- [`.claude/rules/claim-acquire-before-worktree-work.md`](../../../../../../.claude/rules/claim-acquire-before-worktree-work.md) — convergence here was at branch scope, not at backlog-row scope (no claim conflict)
+- [`.claude/rules/substrate-or-it-didnt-happen.md`](../../../../../../.claude/rules/substrate-or-it-didnt-happen.md) — peer-Otto's substrate is what landed; my pre-push commit `cacecad` doesn't exist in any durable surface (correct outcome)