diff --git a/tools/hygiene/check-no-op-cadence-pattern.ts b/tools/hygiene/check-no-op-cadence-pattern.ts
new file mode 100755
index 000000000..b6813b7cb
--- /dev/null
+++ b/tools/hygiene/check-no-op-cadence-pattern.ts
@@ -0,0 +1,357 @@
+#!/usr/bin/env bun
+/**
+ * tools/hygiene/check-no-op-cadence-pattern.ts —
+ * Pre-tick mechanical check for the no-op-cadence failure mode.
+ *
+ * TypeScript port of `check-no-op-cadence-pattern.sh` per the
+ * DST-justifies-TS-quality-over-bash discipline (CLAUDE.md) +
+ * B-0156 TypeScript standardization for non-install scripts.
+ * The bash version remains for cross-shell compatibility; both
+ * are kept in sync.
+ *
+ * Usage:
+ *   bun tools/hygiene/check-no-op-cadence-pattern.ts
+ *
+ * Env vars (parity with bash version):
+ *   NO_OP_CHECK_WINDOW=7        — window size (last N shards)
+ *   NO_OP_CHECK_THRESHOLD=5     — minimal-observation threshold
+ *   NO_OP_CHECK_GAP_MINUTES=15  — shard-density gap threshold
+ *
+ * Exit code: always 0 (informational only; never blocks the tick).
+ */
+
+import { readdirSync, readFileSync, existsSync } from "node:fs";
+import { join } from "node:path";
+import { spawnSync } from "node:child_process";
+
+export type Shard = {
+  primary: string;
+  disamb: string;
+  path: string;
+};
+
+/**
+ * Find repo root via `git rev-parse --show-toplevel`. Falls back to
+ * cwd. Avoids the parent-walk pattern which loops on Windows drive
+ * roots (per repo-scripting.md convention + #1366 P0 finding).
+ */
+export function findRepoRoot(): string {
+  const result = spawnSync("git", ["rev-parse", "--show-toplevel"], {
+    encoding: "utf8",
+  });
+  if (result.status === 0 && result.stdout) {
+    return result.stdout.trim();
+  }
+  return process.cwd();
+}
+
+/**
+ * Parse a positive integer env var with strict full-string numeric
+ * validation. parseInt alone accepts "7abc" → 7, defeating the
+ * validation guard (#1366 P2 finding).
+ */
+export function parsePositiveInt(envName: string, fallback: number): number {
+  const raw = process.env[envName];
+  if (!raw) return fallback;
+  if (!/^[0-9]+$/.test(raw)) {
+    console.error(
+      `[no-op-check] Invalid ${envName}='${raw}' (need positive integer); using default ${fallback}.`
+    );
+    return fallback;
+  }
+  const parsed = parseInt(raw, 10);
+  if (Number.isNaN(parsed) || parsed < 1) {
+    console.error(
+      `[no-op-check] Invalid ${envName}='${raw}' (need positive integer); using default ${fallback}.`
+    );
+    return fallback;
+  }
+  return parsed;
+}
+
+/**
+ * Collect tick-shards from a directory matching the canonical
+ * filename patterns. Returns empty array on missing/unreadable
+ * directory rather than throwing (#1366 P1 finding).
+ */
+export function collectShards(dir: string, dateFlat: string): Shard[] {
+  if (!dateFlat || !existsSync(dir)) return [];
+  let files: string[];
+  try {
+    files = readdirSync(dir).filter((f) => f.endsWith(".md"));
+  } catch {
+    return [];
+  }
+  const shards: Shard[] = [];
+  for (const name of files) {
+    const m1 = name.match(/^(\d{4})Z(?:-([0-9a-f]+))?\.md$/);
+    if (m1) {
+      shards.push({
+        primary: `${dateFlat}${m1[1]}00`,
+        disamb: m1[2] ?? "",
+        path: join(dir, name),
+      });
+      continue;
+    }
+    const m2 = name.match(/^(\d{6})Z-([0-9a-f]+)\.md$/);
+    if (m2) {
+      shards.push({
+        primary: `${dateFlat}${m2[1]}`,
+        disamb: m2[2],
+        path: join(dir, name),
+      });
+    }
+  }
+  return shards;
+}
+
+/**
+ * Minimal-observation regex. `\s` differs between JS and grep -E
+ * meaning; explicit `[ \t]` ensures parity with the bash sibling
+ * (#1366 P1 finding).
+ */
+export const OBSERVATION_CLASS_REGEX =
+  /minimal observation|within-basin observation|observe-only|minimal[ -]not[ -]idle|same\.[ \t]*stopping/i;
+
+export function isMinimalObservation(path: string): boolean {
+  let body = "";
+  let content = "";
+  try {
+    content = readFileSync(path, "utf8");
+    const firstLine = content.split("\n")[0] ?? "";
+    const fields = firstLine.split("|");
+    body = fields[4] ?? "";
+  } catch {
+    return false;
+  }
+  if (body.length < 600) return true;
+  return OBSERVATION_CLASS_REGEX.test(content);
+}
+
+function pad2(n: number): string {
+  return n.toString().padStart(2, "0");
+}
+
+function ymdParts(d: Date): { yyyy: string; mm: string; dd: string } {
+  return {
+    yyyy: d.getUTCFullYear().toString(),
+    mm: pad2(d.getUTCMonth() + 1),
+    dd: pad2(d.getUTCDate()),
+  };
+}
+
+export type CheckArgs = {
+  windowSize: number;
+  threshold: number;
+  gapThresholdMinutes: number;
+  now: Date;
+};
+
+export type CheckResult = {
+  totalShards: number;
+  minObsCount: number;
+  thresholdHit: boolean;
+  gapMinutes: number | null;
+  gapHit: boolean;
+};
+
+export function runCheck(repoRoot: string, args: CheckArgs): CheckResult {
+  const today = ymdParts(args.now);
+  const yesterday = ymdParts(
+    new Date(args.now.getTime() - 24 * 60 * 60 * 1000)
+  );
+
+  const todayDir = join(
+    repoRoot,
+    "docs/hygiene-history/ticks",
+    today.yyyy,
+    today.mm,
+    today.dd
+  );
+  const yesterdayDir = join(
+    repoRoot,
+    "docs/hygiene-history/ticks",
+    yesterday.yyyy,
+    yesterday.mm,
+    yesterday.dd
+  );
+
+  const todayFlat = `${today.yyyy}${today.mm}${today.dd}`;
+  const yesterdayFlat = `${yesterday.yyyy}${yesterday.mm}${yesterday.dd}`;
+
+  const allShards = [
+    ...collectShards(yesterdayDir, yesterdayFlat),
+    ...collectShards(todayDir, todayFlat),
+  ];
+
+  allShards.sort((a, b) => {
+    if (a.primary !== b.primary) return a.primary.localeCompare(b.primary);
+    return a.disamb.localeCompare(b.disamb);
+  });
+
+  const recent = allShards.slice(-args.windowSize);
+
+  if (recent.length === 0) {
+    return {
+      totalShards: 0,
+      minObsCount: 0,
+      thresholdHit: false,
+      gapMinutes: null,
+      gapHit: false,
+    };
+  }
+
+  let minObsCount = 0;
+  for (const shard of recent) {
+    if (isMinimalObservation(shard.path)) minObsCount++;
+  }
+
+  const thresholdHit = minObsCount >= args.threshold;
+
+  let gapMinutes: number | null = null;
+  let gapHit = false;
+  const latest = recent[recent.length - 1];
+  if (latest && latest.primary.length === 14) {
+    const yyyy = latest.primary.substring(0, 4);
+    const mm = latest.primary.substring(4, 6);
+    const dd = latest.primary.substring(6, 8);
+    const hh = latest.primary.substring(8, 10);
+    const mn = latest.primary.substring(10, 12);
+    const ss = latest.primary.substring(12, 14);
+    const latestDate = new Date(`${yyyy}-${mm}-${dd}T${hh}:${mn}:${ss}Z`);
+    if (!Number.isNaN(latestDate.getTime())) {
+      gapMinutes = Math.floor(
+        (args.now.getTime() - latestDate.getTime()) / 60000
+      );
+      gapHit = gapMinutes > args.gapThresholdMinutes;
+    }
+  }
+
+  return {
+    totalShards: recent.length,
+    minObsCount,
+    thresholdHit,
+    gapMinutes,
+    gapHit,
+  };
+}
+
+export function main(): number {
+  const repoRoot = findRepoRoot();
+  process.chdir(repoRoot);
+
+  const args: CheckArgs = {
+    windowSize: parsePositiveInt("NO_OP_CHECK_WINDOW", 7),
+    threshold: parsePositiveInt("NO_OP_CHECK_THRESHOLD", 5),
+    gapThresholdMinutes: parsePositiveInt("NO_OP_CHECK_GAP_MINUTES", 15),
+    now: new Date(),
+  };
+
+  const result = runCheck(repoRoot, args);
+
+  if (result.totalShards === 0) {
+    console.error(
+      `[no-op-check] No shards in window for today or yesterday; nothing to check.`
+    );
+    return 0;
+  }
+
+  console.error(
+    `[no-op-check] Recent ${result.totalShards} shards across today+yesterday; ${result.minObsCount} match minimal-observation pattern (threshold: ${args.threshold}).`
+  );
+
+  if (result.thresholdHit) {
+    console.error("");
+    console.error(
+      `WARNING: no-op-cadence pattern detected — ${result.minObsCount}/${result.totalShards} recent ticks are minimal-observation.`
+    );
+    console.error("");
+    console.error(
+      "Per the just-landed substrate (memory/feedback_party_during_human_sleep_*.md +"
+    );
+    console.error(
+      "memory/feedback_recurrence_after_correction_needs_operational_enforcement_*.md):"
+    );
+    console.error("");
+    console.error(
+      "  - The human-paused phase IS the practice window for independent-production-skill"
+    );
+    console.error("  - Default to minimal observation IS the failure mode");
+    console.error(
+      "  - Party-class operation alternatives: implement a backlog row, do"
+    );
+    console.error(
+      "    free-zone substrate-quality work, write a self-grading memo, audit"
+    );
+    console.error("    cross-references, propose architectural extensions");
+    console.error("");
+    console.error(
+      "  Run with NO_OP_CHECK_THRESHOLD=99 to silence; the default fires the"
+    );
+    console.error(
+      "  warning to surface the pattern at decision-time, not just substrate-read time."
+    );
+  }
+
+  if (result.gapMinutes === null) {
+    console.error(
+      "[no-op-check] No latest-shard primary key available; gap-check skipped."
+    );
+  } else {
+    console.error(
+      `[no-op-check] Most recent shard ${result.gapMinutes} minutes old (gap-threshold: ${args.gapThresholdMinutes}).`
+    );
+    if (result.gapHit) {
+      console.error("");
+      console.error(
+        `WARNING: missing-shard-cadence detected — most recent shard is ${result.gapMinutes} minutes old, exceeding threshold ${args.gapThresholdMinutes} minutes.`
+      );
+      console.error("");
+      console.error(
+        "This is the structural counterpart to the body-length / keyword check above:"
+      );
+      console.error("");
+      console.error(
+        "  - The cron is '* * * * *' (every minute); ticks fire continuously"
+      );
+      console.error(
+        "  - When the agent operates correctly, each substantive tick produces a shard"
+      );
+      console.error(
+        "  - Repeated 'standing by' / minimal-acknowledgment chat output WITHOUT writing shards IS the failure mode"
+      );
+      console.error(
+        "  - Body-length check above doesn't catch this because it requires shards to exist"
+      );
+      console.error(
+        "  - Shard-density check (this) catches the gap structurally without needing chat-transcript scanning"
+      );
+      console.error("");
+      console.error(
+        "  Per memory/feedback_never_idle_speculative_work_over_waiting.md 2026-05-02 refinement:"
+      );
+      console.error(
+        "  proper-order backlog work is available; default-to-standing-by IS the no-op-cadence"
+      );
+      console.error(
+        "  failure mode. Pick a P0/P1 row by depends_on graph + tier; populate depends_on as"
+      );
+      console.error(
+        "  on-demand backfill if missing. Best-guesses-with-time, no rush."
+      );
+      console.error("");
+      console.error(
+        "  Run with NO_OP_CHECK_GAP_MINUTES=99 to silence; the default surfaces the gap"
+      );
+      console.error(
+        "  at decision-time so the agent can re-enter productive cadence."
+      );
+    }
+  }
+
+  return 0;
+}
+
+if (import.meta.main) {
+  process.exit(main());
+}