@@ -132,7 +132,7 @@ that silently does not happen.
 | 23b | **Position-catalog check skipped** — a `sys_user_position` write whose `position` names no position in the security catalog is not refused | plugin-security | Get: a system writer can store an assignment naming no position — the seed loader writes `stack.data` from `AppPlugin.start()` under a system context, as invitation acceptance and the platform's own bootstraps do. Lose: such a row grants nothing and nothing says so. A non-system insert, or a non-system update that changes `position`, is refused `400 VALIDATION_FAILED` / `reference_not_found` instead when the security catalog holds no position of that name: the environment registry (ADR-0131 D3), one per deployment, which takes no organization, so a name only a `sys_position` row carries — any organization's — is refused like one nobody carries. It is the same stand-down as the engine's referential-integrity check for a lookup column | `packages/plugins/plugin-security/src/position-catalog-refusal.ts#assertPositionNamesCatalogRow` |
 | 23c | **Grant-name catalog check skipped** — a `sys_user_permission_set` write whose `permission_set` names no permission set in the security catalog is not refused | plugin-security | Get: a system writer can store a grant naming a set not yet registered — seed replay and boot provisioning may write the grant before the definition it names is registered. Lose: such a row grants nothing and nothing says so. A non-system insert, or a non-system update that changes `permission_set`, is refused `400 VALIDATION_FAILED` / `reference_not_found` instead when the security catalog holds no set by that name; a grant that names no set at all is refused `required` for every caller. The grant names its set by name alone, and nothing derives the name from `permission_set_id` (ADR-0131 D4, D10) | `packages/plugins/plugin-security/src/grant-permission-set-name.ts#onInsert`, `#onUpdate` |
 | 23d | **Grant-holder membership check skipped** — a `sys_user_position` or `sys_user_permission_set` write naming a user with no `sys_member` row in the row's organization is not refused | plugin-security | Get: a system writer can store such a grant — invitation acceptance writes the membership and its placement together, and seed replay, the organization-admin reconcile and the platform bootstraps write grants as the system. Lose: such a row takes effect once its user is admitted to the organization. A non-system insert, or a non-system update that moves `user_id` or `organization_id`, is refused `400 VALIDATION_FAILED` / `reference_not_found` at `user_id` instead, for every caller, a platform administrator included; the membership is read as `{ isSystem: true, tenantId }` with `tenantId` the row's own organization, never another one. A row stored with no organization is not judged. Under `single`, 18.0 stamps a new grant with the Default Organization, so such a row is one an earlier release wrote | `packages/plugins/plugin-security/src/grant-holder-membership-refusal.ts#onInsert`, `#onUpdate` |
-| 24 | Tenant-audit warning silenced; `bypassTenantAudit` threaded to the driver | objectql | Get: unscoped system writes stop warning. Lose: the signal that would flag a genuine user-path scoping bug | `packages/objectql/src/engine.ts#buildDriverOptions` |
+| 24 | Tenant-audit warning silenced; `bypassTenantAudit` threaded to the driver | objectql | Get: unscoped system writes stop warning. Lose: the signal that would flag a genuine user-path scoping bug | `packages/objectql/src/engine-driver-options.ts#buildDriverOptions` |
 | 25 | Engine-owned / append-only write guard bypassed | plugin-security | Get: generic writes to `managedBy` engine-owned objects | `packages/plugins/plugin-security/src/system-write-guard.ts#isUserContextWrite`, `#assertEngineOwnedWriteAllowed` |
 | 26 | Identity write guard bypassed (ADR-0092) | plugin-auth | Get: direct writes to identity tables through the generic data path | `packages/plugins/plugin-auth/src/identity-write-guard.ts#isUserContextWrite` |
 | 26b | API key restore guard does not refuse | plugin-auth | Get: a write setting `revoked: false` on a `sys_api_key` row an administrator's forced password reset revoked is admitted without the platform-administrator check a user-context restore must pass; the reason is still cleared. Lose: nothing a caller reaches: no system writer restores a key, and the mint, the last-used stamp and the forced reset itself never set `revoked: false` | `packages/plugins/plugin-auth/src/api-key-restore-guard.ts#isUserContextWrite` |
 
@@ -0,0 +1,304 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#25522 cut 12] The driver-options and engine-posture bodies of `ObjectQL`,
+ * moved out of `engine.ts` whole: `buildDriverOptions` (the `DriverOptions`
+ * every driver call receives: the transaction handle, the tenant scope, the
+ * timezone and the tenant-audit fill-ins), `driverReadScope` (the Layer 0
+ * verdict projected onto a read's driver scope), `engineLayer0Verdict` (that
+ * verdict over the engine's own facts), `wallExemptedOperation` (did the
+ * wall's exemption lift this operation's scope), `driverWriteTarget` (the
+ * write target of an insert or upsert) and `resolveEnginePosture` (the
+ * tenancy posture in force), with the one module helper only they use:
+ * `accessibleOrganizationsOf`.
+ *
+ * A MOVE, not a redesign. Each exported function below is the body of the
+ * `ObjectQL` method of the same name as it stood, re-indented one level and
+ * otherwise unedited. Each method's docblock stays on the method in
+ * `engine.ts`, which is still the contract. The helper moves with its
+ * docblock, byte for byte, and is not exported.
+ *
+ * Nothing stays behind in this section: every member of it moved.
+ *
+ * ## The transaction seam's same-origin half (ADR-0119, ADR-0067)
+ *
+ * `buildDriverOptions` threads the open transaction handle only to the driver
+ * that owns it (`transactionCoversDriverFor`, which stays in the class). The
+ * ADR anchor entry for this file carries that half of the paragraph the
+ * `engine.ts` entry carried; the `enforceTransactionOrigin` half stays there.
+ *
+ * ## How the moved bodies reach the class
+ *
+ * The shape #23050 set for `rest-server.ts`, applied per method as
+ * `engine-file-reference-hydration.ts` applies it. The class keeps all six
+ * methods with name, modifiers, signature, docblock and position, and each
+ * body is one literal of exactly the {@link DriverOptionsHost} members that
+ * method reads, plus a `.call`. The fields a body reads (`txStore`,
+ * `_registry`, `tenancyPostureProvider`) go as GETTERS, so each read happens
+ * when the body makes it, as it did. The methods they call
+ * (`isClosedUnitHandle`, `transactionCoversDriverFor`, `driverWriteTarget`,
+ * `driverReadScope`, `wallExemptedOperation`, `engineLayer0Verdict`,
+ * `resolveEnginePosture`) go as late-bound closures over the instance, so a
+ * double or spy set on the engine is still the one a call reaches.
+ *
+ * This module imports the engine only as a TYPE, so there is no module cycle
+ * at run time, and nothing re-exports it, so the published surface does not
+ * move.
+ */
+
+import { isTenancyDisabled } from '@objectstack/spec/data';
+import type { ExecutionContext } from '@objectstack/spec/kernel';
+import {
+  // [ADR-0131 D8] The ONE tenant read predicate, shared with plugin-security's
+  // Layer 0 — see {@link buildDriverOptions}.
+  computeTenantLayer0Verdict,
+} from '@objectstack/core';
+import { resolveTenantFieldName } from './tenancy/system-write-organization.js';
+import { resolveTenancyPosture } from '@objectstack/types';
+import {
+  normalizeTenancyPosture,
+  TenantLayer0VerdictSchema,
+  type TenancyPosture,
+  type TenantLayer0Verdict,
+} from '@objectstack/spec/security';
+import { isFederatedObject } from './federated-object.js';
+import type { ObjectQL } from './engine.js';
+
+/**
+ * The `ObjectQL` members the functions below read — every one of them, and no
+ * other; each function's `this` is the `Pick` of the members IT reads. Each is
+ * typed AS the class member (an indexed access on the class), so a change to a
+ * member's type on the class is a change here too, and naming a member the
+ * class does not have is a compile error. See the module header for which
+ * members are getters.
+ */
+export interface DriverOptionsHost {
+  readonly txStore: ObjectQL['txStore'];
+  readonly _registry: ObjectQL['_registry'];
+  readonly tenancyPostureProvider: ObjectQL['tenancyPostureProvider'];
+  isClosedUnitHandle: ObjectQL['isClosedUnitHandle'];
+  transactionCoversDriverFor: ObjectQL['transactionCoversDriverFor'];
+  driverWriteTarget: ObjectQL['driverWriteTarget'];
+  driverReadScope: ObjectQL['driverReadScope'];
+  wallExemptedOperation: ObjectQL['wallExemptedOperation'];
+  engineLayer0Verdict: ObjectQL['engineLayer0Verdict'];
+  resolveEnginePosture: ObjectQL['resolveEnginePosture'];
+}
+
+/**
+ * [ADR-0105 D2] The context's organization access set
+ * (`ExecutionContext.accessible_org_ids`), stringified — `undefined` when
+ * absent or empty, which the verdict reads as "no membership" under `group`.
+ */
+function accessibleOrganizationsOf(execCtx: ExecutionContext | undefined): string[] | undefined {
+  const set = (execCtx as { accessible_org_ids?: unknown } | undefined)?.accessible_org_ids;
+  return Array.isArray(set) && set.length > 0 ? set.map(String) : undefined;
+}
+
+/** The body of `ObjectQL#buildDriverOptions`; the method's docblock there is its contract. */
+export function buildDriverOptions(
+  this: Pick<DriverOptionsHost, 'isClosedUnitHandle' | 'txStore' | 'transactionCoversDriverFor' | '_registry' | 'driverWriteTarget' | 'driverReadScope' | 'wallExemptedOperation'>,
+  object: string,
+  execCtx?: ExecutionContext,
+  base?: any,
+  scope: { writeTarget?: boolean; recordedVerdict?: unknown } = {},
+): any {
+  // The open transaction may arrive explicitly via the context, or ambiently
+  // via txStore when an internal query runs during a transactional write
+  // (ADR-0034). Explicit wins; ambient is the safety net. [#22855] A handle
+  // whose unit has closed is no handle: work the unit started and did not
+  // await runs unenrolled (`runOpenedUnit`).
+  const explicit = execCtx?.transaction;
+  const tx = explicit !== undefined && !this.isClosedUnitHandle(explicit)
+    ? explicit
+    : this.txStore.getStore()?.transaction;
+  // [#5351] SAME-ORIGIN GATE. A transaction handle is a property of ONE
+  // driver's connection; handing it to a different driver does not put that
+  // driver's statement inside the transaction, it executes the statement on
+  // the WRONG CONNECTION — measured on knex/SQLite as `no such table` against
+  // a database that never held the object. The write path's
+  // `enforceTransactionOrigin` has already refused a business write by the
+  // time we get here (and let a system ledger through by decision), so this
+  // is the structural half: whatever survives to here, the handle only ever
+  // reaches the driver that owns it. It covers READS too, which have no gate
+  // of their own and were riding the same wrong connection.
+  const hasTx = tx !== undefined && this.transactionCoversDriverFor(object, tx);
+  const objectSchema = this._registry.getObject(object) as any;
+  // `isFederatedObject` is the same predicate every schema-sync seam routes a
+  // federated object by — one spelling of "this schema is the remote's",
+  // not a second reading of it.
+  const isFederated = isFederatedObject(objectSchema);
+  const tenantObject = !isTenancyDisabled(objectSchema) && !isFederated;
+  const tenantScope = tenantObject
+    ? scope.writeTarget
+      ? this.driverWriteTarget(execCtx)
+      : this.driverReadScope(execCtx, scope.recordedVerdict)
+    : undefined;
+  const hasTenant = tenantScope !== undefined;
+  const hasTz = execCtx?.timezone !== undefined;
+  const isSystem = execCtx?.isSystem === true;
+  // [ADR-0131 D9/D13] The tenant-audit's scope is the object's SCHEMA: a
+  // tenant column (the registered schema's, as `resolveTenantFieldName`
+  // reads it) on an object that is not federated. That is the same reading
+  // the system-insert rule takes, and there is no second, per-table one —
+  // the #13491 ledger that used to narrow this by name retired with D13. An
+  // object is outside the audit only by declaring itself outside the
+  // machinery (`tenancy.enabled: false`, `systemFields.tenant: false`, no
+  // tenant field, `external`), which `scripts/platform-object-tenancy-census.json`
+  // enumerates for the platform namespaces.
+  const isTenantAuditInScope =
+    resolveTenantFieldName(objectSchema) !== null &&
+    !isFederated;
+  // [ADR-0131 D8 · 8c-1] The wall's exemption, declared to the driver. An
+  // exempt platform admin's predicate write reaches the driver with no
+  // `tenantId` because the wall lifted the scope on purpose, and the
+  // driver's `[tenant-audit]` line tells such a write to declare
+  // `bypassTenantAudit: true` — an option no REST caller can set. The
+  // exemption is decided once, by `computeTenantLayer0Verdict`, and arrives
+  // here as the recorded verdict; this reads it, it does not re-decide it
+  // (see {@link wallExemptedOperation}).
+  const wallExempt =
+    tenantObject && isTenantAuditInScope && !scope.writeTarget &&
+    this.wallExemptedOperation(execCtx, scope.recordedVerdict);
+  const preserveAudit = (execCtx as any)?.preserveAudit === true;
+  if (!hasTx && !hasTenant && !isSystem && !hasTz && !preserveAudit && !wallExempt) return base;
+  const opts: any = base && typeof base === 'object' ? { ...base } : {};
+  if (hasTx && opts.transaction === undefined) {
+    opts.transaction = tx;
+  }
+  if (hasTenant && opts.tenantId === undefined) {
+    opts.tenantId = tenantScope.tenantId;
+  }
+  if (hasTenant && opts.tenantIds === undefined && tenantScope.tenantIds !== undefined) {
+    opts.tenantIds = tenantScope.tenantIds;
+  }
+  if (hasTz && opts.timezone === undefined) {
+    // Thread the business timezone so date-dependent driver generation
+    // (autonumber `{YYYYMMDD}` tokens) resolves the calendar day correctly.
+    opts.timezone = execCtx!.timezone;
+  }
+  if (isSystem && opts.bypassTenantAudit === undefined && !isTenantAuditInScope) {
+    // [#13491 → ADR-0131 D13] The isSystem mute, cut by the object's
+    // schema alone (2026-08-31 ruling, execution point 1: the OBJECT decides,
+    // never the caller's flag).
+    //
+    // It used to mute EVERY elevated write, whatever the object was. The
+    // census cited in commit e49d98896's message measured what that cost: 135 of 175 write call sites
+    // (77%) were silenced here — at the control's LARGEST gate, sitting
+    // ahead of the condition the control is about — and the control has
+    // never produced a finding, while all five known instances of the defect
+    // were found by a person reading call sites.
+    //
+    // What still mutes: an object with no tenant field at all (nothing to be
+    // unscoped from — the driver would exit at `resolveTenantField` anyway)
+    // and a federated one. What does not: any object with a tenant column,
+    // platform namespace or not — a name prefix, or a hand-kept list of
+    // names, decides nothing here. A caller that means it still passes
+    // `bypassTenantAudit: true` explicitly and is honoured above — this
+    // branch only fills in a value nobody supplied.
+    //
+    // ⚠️ Direction, per execution point 3: what this ADDS is a driver WARN
+    // line. It changes nothing about what any write touches.
+    opts.bypassTenantAudit = true;
+  }
+  if (wallExempt && opts.bypassTenantAudit === undefined) {
+    // The same fill-in-only rule as the isSystem mute above: a caller's own
+    // value wins. Diagnostics only — the driver's scope is already the
+    // verdict's (no `tenantId`), and this option silences a warning and
+    // touches nothing else; on a read it is inert.
+    opts.bypassTenantAudit = true;
+  }
+  if (preserveAudit && opts.preserveAudit === undefined) {
+    // Historical import (#3493): let the driver keep a supplied `updated_at`
+    // instead of force-stamping now on the update path.
+    opts.preserveAudit = true;
+  }
+  return opts;
+}
+
+/** The body of `ObjectQL#driverReadScope`; the method's docblock there is its contract. */
+export function driverReadScope(
+  this: Pick<DriverOptionsHost, 'engineLayer0Verdict'>,
+  execCtx: ExecutionContext | undefined,
+  recordedVerdict: unknown,
+): { tenantId: string; tenantIds?: string[] } | undefined {
+  const activeOrganization =
+    execCtx?.tenantId !== undefined && execCtx.tenantId !== null && String(execCtx.tenantId) !== ''
+      ? String(execCtx.tenantId)
+      : undefined;
+  const recorded = recordedVerdict === undefined ? undefined : TenantLayer0VerdictSchema.safeParse(recordedVerdict);
+  const verdict = recorded?.success ? recorded.data : this.engineLayer0Verdict(execCtx, activeOrganization);
+  switch (verdict.kind) {
+    case 'none':
+      return undefined;
+    case 'organization':
+      return { tenantId: verdict.organizationId };
+    case 'organizations':
+      return { tenantId: activeOrganization ?? verdict.organizationIds[0], tenantIds: [...verdict.organizationIds] };
+    case 'deny':
+      return activeOrganization !== undefined ? { tenantId: activeOrganization } : undefined;
+  }
+}
+
+/** The body of `ObjectQL#engineLayer0Verdict`; the method's docblock there is its contract. */
+export function engineLayer0Verdict(
+  this: Pick<DriverOptionsHost, 'resolveEnginePosture'>,
+  execCtx: ExecutionContext | undefined,
+  activeOrganization: string | undefined,
+): TenantLayer0Verdict {
+  return computeTenantLayer0Verdict({
+    tenancyPosture: this.resolveEnginePosture(),
+    organizationId: activeOrganization,
+    accessibleOrgIds: accessibleOrganizationsOf(execCtx),
+    // Left to the driver, which resolves the tenant column from the
+    // table it actually built (`resolveTenantField`): an object with no
+    // such column is unscoped there whatever this says. `undefined` is
+    // the verdict's "assume a tenant object", as Layer 0 reads an
+    // unresolved field set.
+    objectHasOrgIdField: undefined,
+    tenancyDisabled: false,
+    // The engine holds no permission sets: no exemption is ITS to grant.
+    posturePermitsCrossTenant: false,
+    isPlatformAdmin: false,
+  });
+}
+
+/** The body of `ObjectQL#wallExemptedOperation`; the method's docblock there is its contract. */
+export function wallExemptedOperation(
+  this: Pick<DriverOptionsHost, 'engineLayer0Verdict'>,
+  execCtx: ExecutionContext | undefined,
+  recordedVerdict: unknown,
+): boolean {
+  if (recordedVerdict === undefined) return false;
+  const recorded = TenantLayer0VerdictSchema.safeParse(recordedVerdict);
+  if (!recorded.success || recorded.data.kind !== 'none') return false;
+  const activeOrganization =
+    execCtx?.tenantId !== undefined && execCtx.tenantId !== null && String(execCtx.tenantId) !== ''
+      ? String(execCtx.tenantId)
+      : undefined;
+  return this.engineLayer0Verdict(execCtx, activeOrganization).kind !== 'none';
+}
+
+/** The body of `ObjectQL#driverWriteTarget`; the method's docblock there is its contract. */
+export function driverWriteTarget(
+  this: Pick<DriverOptionsHost, 'resolveEnginePosture'>,
+  execCtx: ExecutionContext | undefined,
+): { tenantId: string; tenantIds?: string[] } | undefined {
+  if (execCtx?.tenantId === undefined) return undefined;
+  const tenantIds =
+    this.resolveEnginePosture() === 'group' ? accessibleOrganizationsOf(execCtx) : undefined;
+  return { tenantId: execCtx.tenantId as string, ...(tenantIds ? { tenantIds: [...tenantIds] } : {}) };
+}
+
+/** The body of `ObjectQL#resolveEnginePosture`; the method's docblock there is its contract. */
+export function resolveEnginePosture(
+  this: Pick<DriverOptionsHost, 'tenancyPostureProvider'>,
+): TenancyPosture {
+  const injected = normalizeTenancyPosture(this.tenancyPostureProvider?.());
+  if (injected) return injected;
+  try {
+    return resolveTenancyPosture();
+  } catch {
+    return 'isolated';
+  }
+}