skill issue

scripts/skill-check.mjs

@@ -1834,13 +1834,46 @@ record('a week nobody was rostered for is not reported as 0% attendance',
 
 /* ── Anomalies: what it finds, and what it stays quiet about ─────────────── */
 
-const findings = attendance.attendanceAnomalies(SHIFTS);
+/* Anchored, not live.
+ *
+ * These shifts are generated by counting back from a day, and which of them
+ * land in a *complete* week depends on where that day sits in one. Asserting
+ * against the live set meant asserting against the calendar: the seeded
+ * overtime climb is detected on a Thursday and not on a Friday, so this check
+ * failed every Friday and Saturday and passed the rest of the week.
+ *
+ * The anchor is the same instant the rest of this file pins, and the same date
+ * is passed as `now` — shifts built around one day and bucketed around another
+ * describe two different windows, which is its own way to be wrong. */
+const ANCHOR = new Date('2026-08-20T09:00:00.000Z');
+const ANCHORED_SHIFTS = shiftSeed.buildShiftsAt(ANCHOR);
+const findings = attendance.attendanceAnomalies(ANCHORED_SHIFTS, { now: ANCHOR });
 record('the seeded attendance decline is found',
   findings.some((f) => f.kind === 'attendance'),
   findings.filter((f) => f.kind === 'attendance').map((f) => f.title).join(' | ') || 'NOT FOUND');
 record('the seeded overtime climb is found',
   findings.some((f) => f.kind === 'overtime'),
   findings.find((f) => f.kind === 'overtime')?.detail || 'NOT FOUND');
+
+/* And that it does not depend on the day, measured rather than assumed.
+ *
+ * Pinning the anchor makes this file deterministic; it does not make the
+ * product insensitive to the day, and it was not: the climb was reported Sunday
+ * through Thursday and vanished on Friday and Saturday, because the oldest week
+ * in the window is a partial one and thinned to two shifts as the week wore on,
+ * inflating the baseline every later week was compared against.
+ *
+ * Fixed in attendanceAnomalies by dropping a leading week rostered well below
+ * the usual. This is the number that keeps it fixed: a change that reintroduces
+ * a calendar-shaped blind spot fails here even though the pinned assertion
+ * above still passes. */
+const detectableOn = Array.from({ length: 28 }, (_, i) => new Date(2026, 7, i + 1, 12))
+  .filter((day) => attendance
+    .attendanceAnomalies(shiftSeed.buildShiftsAt(day), { now: day })
+    .some((f) => f.kind === 'overtime')).length;
+record('the seeded overtime climb is detectable on every day of the week',
+  detectableOn === 28,
+  `${detectableOn}/28 anchors`);
 record('every finding carries the figures behind it',
   findings.every((f) => f.title && f.detail && f.severity && f.metric));
 record('findings are ordered most severe first',