shard(tick): 2026-05-16T07:27Z — B-0509 = 2nd FP class (2nd in a row); FP-rate pattern noted

docs/hygiene-history/ticks/2026/05/16/0727Z.md

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+# Tick 2026-05-16T07:27Z — Otto-CLI
+
+Twenty-seventh tick of the resume-session series. Rate at
+**1132/5000** (cost-aware tier; 1 PR/tick max). Audited B-0509 —
+**second 2nd-FP-class verification in a row**. NOT drift; leave
+open. Documenting the empirical FP-rate pattern for the audit tool.
+
+## Refresh result
+
+| Surface | State |
+|---|---|
+| Cron sentinel | Alive (`bd1c7739`) |
+| Rate limit (GraphQL) | **1132/5000** (cost-aware tier) |
+| `origin/main` | Advanced — peer landed PRs #3790 (B-0557 slice 3 chdir) + #3796 (Lior shadow log) |
+
+## Audit: B-0509 — 2nd FP class confirmed
+
+[B-0509](../../../../../backlog/P1/B-0509-b0448-slice3-install-ts-cloud-schedule-extension-2026-05-14.md) (`B-0448 slice 3 — Extend tools/routines/install.ts to detect + surface cloud-schedule.json`). Path flagged: `tools/routines/install.ts`.
+
+**Per-acceptance grep** (zero gh):
+
+```bash
+grep -E 'cloud.schedule|cloud-schedule' tools/routines/install.ts
+# (no matches)
+```
+
+Acceptance items 1-4 specifically reference `readCloudSchedule` /
+`cloudSchedule` field / "Cloud Routine next-step guidance" — none of
+which exist in the current `install.ts`. The file exists for
+**B-0448 slice 1** (original install scaffolding); the B-0509-specific
+cloud-schedule extension was **never shipped**.
+
+**Conclusion**: **2nd FP class** (same as B-0418 last tick). NOT
+drift; do NOT close. Leave row open as accurately reflecting
+unimplemented work.
+
+## Empirical FP-rate observation
+
+Two consecutive 2nd-FP-class verifications (B-0418 + B-0509) on
+candidates flagged by the audit tool. The pattern:
+
+| Row | Primary artifact path | Actual ship target | Acceptance miss |
+|---|---|---|---|
+| B-0418 | `tools/dashboard/generate-metrics.ts` | B-0414 | `amplification_ratio_today` field absent |
+| B-0509 | `tools/routines/install.ts` | B-0448 slice 1 | `cloud-schedule` references absent |
+
+In both cases, the path is a **shared tool** that was originally
+shipped for a DIFFERENT row. The audit tool's single-artifact-
+existence check can't distinguish.
+
+**Hypothesis for future-tool-improvement** (peer Otto's B-0557 lane):
+add a "feature-grep" sub-check that scans the artifact for
+acceptance-named identifiers. If the named API/field/method
+doesn't appear in the artifact, demote the candidate from
+drift-candidate to FP.
+
+## Drift-audit progress tally
+
+After this tick:
+
+| Class | Count | Examples |
+|---|---|---|
+| 1 (Pure drift, closed) | 8 | B-0506/B-0530/B-0535/B-0494 + 4 peer |
+| 2 (Partial, Status-annotated) | 4 | B-0517/B-0537/B-0532/B-0533 |
+| 3 (Multi-slice, children open, verified) | 1 | B-0440 |
+| 4 (Multi-slice, all children closed, closed) | 1 | B-0159 |
+| FP (2nd FP class verified) | **2** | B-0418, **B-0509 (this tick)** |
+| **Total triaged** | **16 of ~38** | |
+
+> Fix-up commit: removed B-0159 from class 1 examples (per Codex
+> review of original commit). B-0159 is class 4 (multi-slice,
+> children all closed); the class 1 listing was a stale carry-over
+> from prior tick. Class 1 count: 9 → 8. Total triaged: 17 → 16.
+
+## Sentinel + close
+
+`CronList`: `bd1c7739` alive.
+
+## Visibility signal
+
+- B-0509 verified as 2nd FP class (no edit)
+- FP-rate pattern noted: shared-tool paths are FP-prone
+- Hypothesis filed for peer's audit-tool-improvement lane
+- Sentinel `bd1c7739` alive
+- Rate 1132/5000 (cost-aware)
+- ~21 audit candidates remaining