diff --git a/packages/drivers/driver-sql/src/sql-driver-13567-audit-stamp-materialisation.test.ts b/packages/drivers/driver-sql/src/sql-driver-13567-audit-stamp-materialisation.test.ts
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+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#13567] What the record read door materialises `updated_at` AS, per dialect
+ * — the composed fact #13382 was a production bug about, pinned in the package
+ * the live servers are attached to.
+ *
+ * ## The gap this closes, stated as a coverage fact
+ *
+ * The record-data optimistic-concurrency gate (`assertVersionOf` /
+ * `assertVersionMatch` in `@objectstack/metadata-protocol`) compared a record's
+ * `updated_at` against the caller's token with `String(v)` on both sides. On
+ * Postgres — the production default driver — `updated_at` arrives as a JS
+ * `Date`, so the comparison ran
+ *
+ * ```
+ * Sun Aug 30 2026 18:19:25 GMT+0800 (China Standard Time)   ← the driver's value
+ * 2026-08-30T10:19:25.947Z                                  ← the client's echo
+ * ```
+ *
+ * One instant, two spellings, strict string compare: every guarded save
+ * answered `409 CONCURRENT_UPDATE`, on records nobody had touched.
+ *
+ * It survived because EVERY existing OCC pin drives ISO text on both sides — a
+ * memory or mocked engine, or SQLite, all of which round-trip canonical ISO
+ * strings. Those pins were green the whole time the production default driver
+ * refused every write. The discriminating input is the driver's `Date`, and
+ * nothing in the repo ever produced it into that seam.
+ *
+ * `@objectstack/metadata-protocol` has no driver dependency and must not grow
+ * one — the layering runs the other way — so the seam's own regression suite
+ * necessarily drives a hand-made `Date`. That is correct and catches a revert
+ * of the repair. What it cannot assert is the half that made the bug real:
+ * **this driver, on these dialects, hands a `Date` out of its record read
+ * door.** That half is asserted here, where a live Postgres and a live MySQL
+ * actually exist (`Temporal Conformance (live PG + MySQL)`).
+ *
+ * ## Not over-pinning: the driver states this decision deliberately
+ *
+ * `withPostgresCalendarDayAsText` installs a text parser for `date` and
+ * `date[]` and says, in as many words, why the instant types are left alone:
+ * *"`timestamptz` / `timestamp` are deliberately untouched: those are instants,
+ * a `Date` is the right materialisation for them, and `Field.datetime` depends
+ * on it."* This file pins that stated decision at the door a consumer reads it
+ * through, and the SQLite side of the same asymmetry alongside it.
+ *
+ * ## Which half rests on which evidence
+ *
+ * §A is pure JavaScript — `Date.prototype.toString` renders whole seconds in
+ * the PROCESS's zone while `toISOString` renders milliseconds in UTC. It needs
+ * no server, so it runs on every runner including Test Core, and it is the half
+ * that can be measured anywhere.
+ *
+ * §B is the DIALECT fact and only a live server can answer it: what
+ * `SqlDriver#findOne` puts in `updated_at`. The SQLite cell runs everywhere and
+ * pins the ISO-text side — the accident that kept every OCC pin green; the two
+ * live cells pin the `Date` side and are the reason this file lives in
+ * `driver-sql` rather than next to the seam.
+ *
+ * ## Why the audit column and not a declared `Field.datetime`
+ *
+ * `created_at` / `updated_at` are BUILTIN columns, so they are not in
+ * `datetimeFields` and no declared-field coercion reaches them. `formatOutput`
+ * repairs them only inside its `if (this.isSqlite)` arm
+ * (`repairNaiveUtcAuditTimestamp` over `AUDIT_TIMESTAMP_COLUMNS`), which is
+ * precisely why the two live dialects hand the raw client value through — and
+ * why `updated_at`, not some other datetime, is the value the OCC seam reads.
+ */
+
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { SqlDriver } from './index.js';
+import { DIALECT_CELLS, declareDialectCell, type DialectCell } from './live-dialect-matrix.testkit.js';
+
+/** Driver options every write here uses — this fixture is not tenant-scoped. */
+const OPTS = { bypassTenantAudit: true } as any;
+
+const TABLE = 'os13567_stamp';
+
+/**
+ * How many create + read-back rounds each cell measures.
+ *
+ * Sized for §B4's non-vacuity guard rather than for coverage: `String(Date)`
+ * drops milliseconds, which is only OBSERVABLE on a stamp that carried some.
+ * Postgres' `CURRENT_TIMESTAMP` is microsecond-precision and MySQL's `now(3)`
+ * is millisecond-precision, so a stamp landing on an exact `.000` is ~1 in
+ * 1000 — rare, but not impossible, and a run in which every stamp did would
+ * report a green that no truncation could have perturbed. Six independent
+ * rounds put that at ~1e-18, the same sizing `#11224` uses one file over.
+ */
+const ROUNDS = 6;
+
+/** Canonical audit-timestamp text — the shape SQLite stores and returns. */
+const ISO_Z = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/;
+
+/**
+ * The tail of `Date.prototype.toString` — `HH:mm:ss` with NO fractional digits,
+ * followed by the zone offset it bakes in.
+ *
+ * Normative since ES2018 (`ToDateString` = DateString + TimeString +
+ * TimeZoneString); only the trailing parenthesised zone NAME is
+ * implementation-defined, so nothing here depends on it.
+ */
+const WHOLE_SECONDS_AND_ZONE = / \d{2}:\d{2}:\d{2} GMT[+-]\d{4}/;
+
+/** The instant from the production report, kept verbatim. */
+const REPORTED_INSTANT = '2026-08-30T10:19:25.947Z';
+
+/**
+ * Run `body` with the process pinned to `tz`, then restore.
+ *
+ * The zone is FORCED rather than required, so §A and §B3 are non-vacuous on any
+ * runner: `Temporal Conformance` pins `TZ=America/New_York`, Test Core runs at
+ * UTC, and a developer runs at whatever their laptop is set to. Restoring
+ * rather than assuming matters because vitest reuses a worker across files — a
+ * leaked `TZ` would silently re-zone whatever runs next in this process, which
+ * is asserted below rather than trusted.
+ *
+ * The sibling copy in `sql-driver-11389-date-tz-skew.test.ts` is deliberately
+ * left alone: this is a zone-scoping utility, not a guard that could weaken in
+ * one copy and nowhere else.
+ */
+async function underProcessZone<T>(tz: string, body: () => Promise<T> | T): Promise<T> {
+  const previous = process.env.TZ;
+  process.env.TZ = tz;
+  try {
+    return await body();
+  } finally {
+    if (previous === undefined) delete process.env.TZ;
+    else process.env.TZ = previous;
+  }
+}
+
+/** Minutes east of UTC, read out of a `Date.prototype.toString` rendering. */
+function offsetInSpelling(spelled: string): number {
+  const m = /GMT([+-])(\d{2})(\d{2})/.exec(spelled);
+  if (!m) throw new Error(`no GMT offset in ${JSON.stringify(spelled)}`);
+  return collapseNegativeZero((m[1] === '-' ? -1 : 1) * (Number(m[2]) * 60 + Number(m[3])));
+}
+
+/**
+ * The PROCESS's current offset for `at`, in minutes east of UTC.
+ *
+ * `getTimezoneOffset()` reports minutes WEST, so it is flipped here to match
+ * the sign every `GMT+hhmm` spelling carries — and the flip is the reason
+ * {@link collapseNegativeZero} exists.
+ */
+function processOffsetEastOfUtc(at: Date): number {
+  return collapseNegativeZero(0 - at.getTimezoneOffset());
+}
+
+/**
+ * Collapse `-0` onto `+0`.
+ *
+ * Not cosmetic, and measured on this file's own first run: `expect(x).toBe(y)`
+ * is `Object.is`, and `Object.is(-0, 0)` is FALSE. At UTC the spelling parses
+ * to `+0` while negating a zero `getTimezoneOffset()` produces `-0`, so §A2's
+ * UTC cell went red on two values that denote the same offset. The matrix
+ * testkit's own `eastOfUtc` makes the same collapse for the same reason (there
+ * it was found by sabotage, here by running).
+ */
+function collapseNegativeZero(minutes: number): number {
+  return minutes === 0 ? 0 : minutes;
+}
+
+// ── §A The JavaScript half — measurable on any runner, no server ────────────
+
+describe('#13567 §A — what `String(Date)` spells, and what it drops', () => {
+  it('§A1 spells the reported instant exactly as the incident recorded it', async () => {
+    const value = new Date(REPORTED_INSTANT);
+    // The prefix only: the trailing `(China Standard Time)` is the one
+    // implementation-defined part of `toString`, and pinning an ICU display
+    // name would make this file fail on a tzdata refresh rather than on a
+    // regression.
+    const spelled = await underProcessZone('Asia/Shanghai', () => String(value));
+    expect(spelled.startsWith('Sun Aug 30 2026 18:19:25 GMT+0800')).toBe(true);
+    // The two sides of the comparison the seam used to make, verbatim.
+    expect(value.toISOString()).toBe(REPORTED_INSTANT);
+    expect(spelled).not.toBe(REPORTED_INSTANT);
+  });
+
+  it('§A2 renders whole seconds in the PROCESS zone, whatever that zone is', async () => {
+    const value = new Date(REPORTED_INSTANT);
+    expect(value.getMilliseconds(), 'the fixture is vacuous without sub-second digits').toBe(947);
+
+    const spellings = new Map<string, string>();
+    for (const tz of ['Asia/Shanghai', 'America/New_York', 'UTC', 'Pacific/Chatham']) {
+      await underProcessZone(tz, () => {
+        const spelled = String(value);
+        spellings.set(tz, spelled);
+        expect(spelled, `${tz}: no whole-second + offset tail`).toMatch(WHOLE_SECONDS_AND_ZONE);
+        // The offset baked into the spelling IS the process's, not UTC's.
+        expect(offsetInSpelling(spelled), `${tz}: spelled offset`).toBe(processOffsetEastOfUtc(value));
+        // The milliseconds are gone: the rendering names an instant `getMilliseconds()`
+        // earlier than the value it was rendered from.
+        expect(Date.parse(spelled), `${tz}: parsed back`).toBe(value.getTime() - value.getMilliseconds());
+      });
+    }
+
+    // One instant, one `Date`, four process zones, four different spellings —
+    // which is what "carries the process zone" means, asserted without
+    // depending on any particular offset being what tzdata says today.
+    expect(new Set(spellings.values()).size, `${JSON.stringify([...spellings])}`).toBe(spellings.size);
+  });
+
+  it('§A3 restores the ambient process zone', async () => {
+    const before = Intl.DateTimeFormat().resolvedOptions().timeZone;
+    await underProcessZone('Pacific/Kiritimati', () => {
+      expect(Intl.DateTimeFormat().resolvedOptions().timeZone).toBe('Pacific/Kiritimati');
+    });
+    expect(Intl.DateTimeFormat().resolvedOptions().timeZone).toBe(before);
+  });
+});
+
+// ── §B The dialect half — what the read door actually hands back ────────────
+
+function measure(cell: DialectCell): void {
+  describe(`#13567 §B — \`updated_at\` as the record read door materialises it (${cell.label})`, () => {
+    let driver: SqlDriver;
+    const rows: any[] = [];
+
+    beforeAll(async () => {
+      driver = new SqlDriver(cell.config());
+      await driver.execute(`drop table if exists ${TABLE}`).catch(() => {});
+      // The DDL path, so the audit columns are the ones
+      // `createAuditTimestampColumn` produces: `timestamptz` on Postgres,
+      // `DATETIME(3)` on MySQL, TEXT on SQLite. That pairing is the whole
+      // subject — the column type is what decides the materialised JS type.
+      await driver.initObjects([
+        { name: TABLE, fields: { id: { type: 'text' }, title: { type: 'string' } } },
+      ] as any);
+      for (let i = 0; i < ROUNDS; i++) {
+        const id = `r${i}`;
+        await driver.create(TABLE, { id, title: 'one' }, OPTS);
+        // `findOne` deliberately, and NOT a raw knex read: this is the door the
+        // OCC seam probes through (`probeRecord` → `engine.findOne`), so a
+        // read-side coercion that normalised the value would be IN scope here
+        // and must be visible to the assertions below.
+        rows.push(await driver.findOne(TABLE, { where: { id } }, OPTS));
+      }
+    }, 60_000);
+
+    afterAll(async () => {
+      await driver?.execute(`drop table if exists ${TABLE}`).catch(() => {});
+      await driver?.disconnect();
+    });
+
+    it('§B0 the read door returned a row per round, carrying `updated_at`', () => {
+      // Guards the vacuous pass: every assertion below reads `updated_at` off
+      // these rows, so a door that did not select the column at all would let
+      // them all pass having checked nothing.
+      expect(rows).toHaveLength(ROUNDS);
+      for (const row of rows) {
+        expect(row, 'findOne returned nothing').toBeTruthy();
+        expect(
+          row.updated_at,
+          'the record read door did not return `updated_at` — the OCC seam reads this exact key',
+        ).toBeDefined();
+        expect(row.updated_at).not.toBeNull();
+      }
+    });
+
+    if (cell.id === 'sqlite') {
+      it('§B1 hands `updated_at` back as canonical ISO-8601-Z TEXT', () => {
+        for (const row of rows) {
+          expect(typeof row.updated_at, `updated_at type for ${row.id}`).toBe('string');
+          expect(row.updated_at).toMatch(ISO_Z);
+        }
+      });
+
+      it('§B2 `String()` of it IS the token a client echoes — the accident that hid the defect', () => {
+        // This is the control, and the reason this file exists: on the dialect
+        // every OCC pin was written against, the naive `String(v)` comparison
+        // matches BY ACCIDENT, because the stored value already is the
+        // canonical spelling the client was served.
+        const value = rows[0].updated_at as string;
+        expect(String(value)).toBe(value);
+        expect(new Date(value).toISOString()).toBe(value);
+      });
+    } else {
+      it('§B1 hands `updated_at` back as a JS `Date`', () => {
+        // The composed fact. `timestamptz` (Postgres, via node-pg's stock OID
+        // 1184 parser — `withPostgresCalendarDayAsText` overrides only `date`
+        // and `date[]`) and `DATETIME(3)` (MySQL, via mysql2's `parseDateTime`
+        // under the `timezone: 'Z'` pin `withUtcSession` installs) both
+        // materialise as a `Date`, and `formatOutput`'s audit-column repair is
+        // SQLite-gated, so nothing downstream converts it.
+        for (const row of rows) {
+          expect(
+            row.updated_at instanceof Date,
+            `${cell.label} returned updated_at as ${typeof row.updated_at} ` +
+              `(${JSON.stringify(String(row.updated_at))}) — the OCC seam's Date handling is ` +
+              `pinned against a shape this dialect no longer produces`,
+          ).toBe(true);
+        }
+        // A real instant, not an Invalid Date dressed up as one.
+        for (const row of rows) expect(Number.isFinite((row.updated_at as Date).getTime())).toBe(true);
+      });
+
+      it('§B3 `String()` of it is NOT the token the client echoes, and follows the process zone', async () => {
+        const value = rows[0].updated_at as Date;
+        // What the GET served and what the client hands back as its next
+        // `If-Match`: a `Date` leaves this process as its ISO-8601 form.
+        const echoed = value.toISOString();
+        expect(echoed).toMatch(ISO_Z);
+
+        const shanghai = await underProcessZone('Asia/Shanghai', () => String(value));
+        const newYork = await underProcessZone('America/New_York', () => String(value));
+
+        for (const [tz, spelled] of [['Asia/Shanghai', shanghai], ['America/New_York', newYork]] as const) {
+          expect(spelled, `${tz}: shape`).toMatch(WHOLE_SECONDS_AND_ZONE);
+          expect(
+            spelled === echoed,
+            `${tz}: a strict String() compare of the driver's value against the client's echoed ` +
+              `token is the comparison #13382 made — ${JSON.stringify(spelled)} vs ` +
+              `${JSON.stringify(echoed)}`,
+          ).toBe(false);
+        }
+
+        // One `Date`, two process zones, two spellings: the process zone is
+        // baked into the rendering. Asserted by DIFFERENCE rather than against
+        // a literal offset, so no tzdata value is pinned here.
+        expect(
+          shanghai,
+          `the same instant spelled identically under two different process zones — ` +
+            `${JSON.stringify(shanghai)}`,
+        ).not.toBe(newYork);
+        expect(offsetInSpelling(shanghai)).not.toBe(offsetInSpelling(newYork));
+      });
+
+      it('§B4 `String()` drops the milliseconds the echoed token carries', async () => {
+        const withMillis = rows.filter((row) => (row.updated_at as Date).getMilliseconds() !== 0);
+        expect(
+          withMillis.length,
+          `none of the ${ROUNDS} stamps in this run carried sub-second digits, so nothing here ` +
+            `could have observed the millisecond loss — the cell measured nothing`,
+        ).toBeGreaterThan(0);
+
+        for (const row of withMillis) {
+          const value = row.updated_at as Date;
+          const echoed = value.toISOString();
+          // The echoed token names the instant exactly …
+          expect(echoed, `${row.id}: echoed token`).toMatch(/\.\d{3}Z$/);
+          expect(Date.parse(echoed), `${row.id}: echoed token instant`).toBe(value.getTime());
+          // … while its `String()` names one `getMilliseconds()` earlier. Read
+          // in the ambient zone the suite is running under, which is the zone
+          // the seam's `String(v)` would have used.
+          expect(Date.parse(String(value)), `${row.id}: spelled instant`).toBe(
+            value.getTime() - value.getMilliseconds(),
+          );
+          expect(Date.parse(String(value))).not.toBe(Date.parse(echoed));
+        }
+      });
+    }
+  });
+}
+
+// A matrix that silently finds zero cells reports OK — every cell is declared
+// EITHER WAY, measured when it is provisioned and a named skip when it is not
+// (a named RED under `OS_EXPECT_LIVE_DIALECT_MATRIX=1`).
+for (const cell of DIALECT_CELLS) {
+  declareDialectCell(cell, 'audit stamp materialisation (#13567)', measure);
+}