@@ -0,0 +1,14 @@
+---
+"@objectstack/plugin-security": patch
+---
+
+The delegated-administration gate resolves a scope's business-unit anchor **inside the caller's own organization**. In a single-database multi-org posture (ADR-0105 D1 `group` / `isolated`) a unit name shared by two organizations no longer crosses the boundary in either direction (#19775).
+
+`sys_business_unit.name` carries no uniqueness — the object's only unique index is `(code, organization_id)` — yet the gate looked the anchor up by name alone under a bare `{ isSystem: true }` context, which carries no tenant. The engine threads a tenant to the driver only when `execCtx.tenantId` is defined and `SqlDriver.applyTenantScope` returns early without one, so nothing scoped that read: a `limit: 1` lookup answered whichever id the driver ordered first, and which organization won was an id ordering. Measured on a real engine over a real SQL driver, with two organizations each holding a unit called `sales`, both directions were wrong at once — the delegate **lost its own subtree** (denied inside its own unit) while the gate **approved** a delegated write anchored in the other organization, and `describeDelegableScope` handed that organization's unit ids back to the caller.
+
+- **What changed**: the anchor read, the descendant walk and the two catalog reads behind `describeDelegableScope` now carry the caller's organization — `organizationId ?? tenantId`, the same spelling the permission-set load already resolves a caller's authority with — and the candidates that come back are reduced to the caller's own rows. Both arms are load-bearing and each was measured to be: the driver's compatibility arm deliberately also returns organization-less rows, and a driver with no tenant scoping at all returns every organization's.
+- **Fail closed**: an anchor that resolves to no unit of the caller's own organization now approves nothing, exactly as a misconfigured scope already did. Under a walled posture this also refuses an **organization-less** business unit, which that posture already treats as invalid state; a delegation anchored on one stops resolving and must be re-anchored on a unit the organization owns.
+- **`group` posture**: the anchor resolves in the caller's **active** organization, not their whole membership set — the narrower of the two, and the one the caller's permission sets (and therefore the `adminScope` itself) were already loaded in.
+- **Unchanged where there is no boundary to cross**: a caller carrying no organization (the `single` posture) keeps the by-name answer it had.
+
+No exported symbol and no payload key was added: `describeDelegableScope` and `scopesCoverUser` take the caller's context as a new optional argument, and omitting it resolves exactly as before.
@@ -0,0 +1,281 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * The delegated-admin gate resolves a scope's business-unit anchor INSIDE the
+ * caller's own organization — pinned over a real engine, at the crossing.
+ *
+ * ## The defect this exists to keep closed
+ *
+ * `sys_business_unit.name` carries no uniqueness (the object's only unique
+ * index is `(code, organization_id)`), so in a single-database multi-org
+ * posture — ADR-0105 D1 `group` / `isolated`, which ADR-0132 ships open — two
+ * organizations may each hold a unit called `sales`. The gate looked the
+ * anchor up by NAME alone under a bare `{ isSystem: true }` context, which
+ * carries no tenant: the engine threads a tenant to the driver only when
+ * `execCtx.tenantId` is defined, and `SqlDriver.applyTenantScope` returns
+ * early without one. So nothing scoped that read, `limit: 1` answered
+ * whichever id the driver ordered first, and which organization won was an id
+ * ordering.
+ *
+ * Both directions were wrong at once, and both are pinned below:
+ *   - the org A delegate LOST its own subtree (denied inside its own unit);
+ *   - the gate APPROVED a delegated write anchored in org B, and
+ *     `describeDelegableScope` handed org B's unit ids to the org A caller.
+ *
+ * ## Why a real engine and a real driver
+ *
+ * The crossing IS the tenant scoping, so a fake `ql` that ignores `context`
+ * cannot exercise it — it would only re-assert this file's own beliefs. Here
+ * the ids are ordered so org B's sort first (`bu_0_*` before `bu_a_*`): under
+ * the old resolution every assertion below flips, and insertion order makes no
+ * difference because the SQL driver's `limit` read is `ORDER BY id ASC`.
+ * `delegated-admin-gate.test.ts` pins the complementary half on a fake `ql`
+ * that scopes NOTHING — the row-level arm that stands even where a driver has
+ * no tenant scoping at all.
+ *
+ * Harness lineage: `tenant-layer0-verdict-end-to-end.test.ts` (a real
+ * `ObjectQL` over a real `SqlDriver` on in-memory SQLite).
+ */
+
+import { describe, it, expect, afterEach } from 'vitest';
+import { ObjectQL } from '@objectstack/objectql';
+import { SqlDriver } from '@objectstack/driver-sql';
+import type { PermissionSet } from '@objectstack/spec/security';
+import { DelegatedAdminGate } from './delegated-admin-gate.js';
+
+const ORG_A = 'org_a_acme';
+/** Deliberately sorts BEFORE every `org_a`/`bu_a` id — the losing side of the defect. */
+const ORG_B = 'org_0_globex';
+
+const text = (name: string) => ({ name, type: 'text' as const });
+const object = (name: string, fields: string[]) => ({
+  name,
+  label: name,
+  fields: {
+    id: { name: 'id', type: 'text' as const, primaryKey: true },
+    organization_id: text('organization_id'),
+    ...Object.fromEntries(fields.map((f) => [f, text(f)])),
+  },
+});
+
+const OBJECTS = [
+  object('sys_business_unit', ['name', 'parent_business_unit_id']),
+  object('sys_position', ['name', 'delegatable']),
+  object('sys_permission_set', ['name', 'admin_scope']),
+  object('sys_position_permission_set', ['position_id', 'permission_set_id']),
+  object('sys_user_position', ['user_id', 'position', 'business_unit_id', 'granted_by', 'delegated_from']),
+  object('sys_business_unit_member', ['user_id', 'business_unit_id']),
+  object('sys_user', ['primary_business_unit_id']),
+];
+
+/** The delegate's scope: anchored at the unit NAMED `sales`, subtree included. */
+const SALES_SCOPE = {
+  businessUnit: 'sales',
+  includeSubtree: true,
+  manageAssignments: true,
+  manageBindings: false,
+  authorEnvironmentSets: false,
+  assignablePermissionSets: ['sales_user'],
+};
+
+const DELEGATE_SETS = [
+  { name: 'member_default', objects: {} },
+  {
+    name: 'sales_admin',
+    objects: { sys_user_position: { allowRead: true, allowCreate: true, allowEdit: true, allowDelete: true } },
+    adminScope: SALES_SCOPE,
+  },
+] as unknown as PermissionSet[];
+
+const engines: ObjectQL[] = [];
+afterEach(async () => {
+  while (engines.length) {
+    try { await engines.pop()?.destroy(); } catch { /* noop */ }
+  }
+});
+
+const sysCtx = (organizationId: string) => ({ isSystem: true, tenantId: organizationId });
+
+async function bootEngine() {
+  const engine = new ObjectQL();
+  engine.registerDriver(
+    new SqlDriver({ client: 'better-sqlite3', connection: { filename: ':memory:' }, useNullAsDefault: true }),
+    true,
+  );
+  await engine.init();
+  engine.registerApp({
+    id: 'com.objectstack.qa.delegated-admin-cross-organization',
+    name: 'Delegated admin cross-organization anchor',
+    version: '1.0.0',
+    type: 'plugin',
+    scope: 'system',
+    objects: OBJECTS,
+  } as any);
+  await engine.syncSchemas();
+  engines.push(engine);
+  return engine;
+}
+
+/**
+ * One organization's slice of the fixture: a unit named `sales` with one
+ * child, a `sales_rep` position distributing the allowlisted `sales_user`
+ * set, and one member. `idPrefix` decides how this organization's ids sort.
+ */
+async function seedOrganization(engine: ObjectQL, organizationId: string, idPrefix: string) {
+  const ctx = sysCtx(organizationId);
+  const ids = {
+    sales: `bu_${idPrefix}_sales`,
+    salesEast: `bu_${idPrefix}_sales_east`,
+    position: `pos_${idPrefix}_sales_rep`,
+    set: `ps_${idPrefix}_sales_user`,
+    user: `usr_${idPrefix}_member`,
+  };
+  await engine.insert('sys_business_unit', [
+    { id: ids.sales, name: 'sales', parent_business_unit_id: null },
+    { id: ids.salesEast, name: 'sales_east', parent_business_unit_id: ids.sales },
+  ], { context: ctx } as any);
+  await engine.insert('sys_position', [{ id: ids.position, name: 'sales_rep' }], { context: ctx } as any);
+  await engine.insert('sys_permission_set', [{ id: ids.set, name: 'sales_user' }], { context: ctx } as any);
+  await engine.insert('sys_position_permission_set', [
+    { id: `bind_${idPrefix}`, position_id: ids.position, permission_set_id: ids.set },
+  ], { context: ctx } as any);
+  await engine.insert('sys_user', [{ id: ids.user, primary_business_unit_id: ids.salesEast }], { context: ctx } as any);
+  await engine.insert('sys_business_unit_member', [
+    { id: `mem_${idPrefix}`, user_id: ids.user, business_unit_id: ids.salesEast },
+  ], { context: ctx } as any);
+  return ids;
+}
+
+function gateOn(engine: ObjectQL) {
+  return new DelegatedAdminGate({
+    ql: engine,
+    resolveSets: async (context: any) => (context?.principal === 'delegate' ? DELEGATE_SETS : []),
+  });
+}
+
+/** The org A delegate's own execution context, as a transport would carry it. */
+const delegateCtx = (organizationId: string) => ({
+  principal: 'delegate',
+  userId: 'usr_delegate',
+  tenantId: organizationId,
+  positions: ['sales_admin'],
+});
+
+const assignInto = (gate: DelegatedAdminGate, organizationId: string, businessUnitId: string, userId: string) =>
+  gate.assert({
+    object: 'sys_user_position',
+    operation: 'insert',
+    data: { user_id: userId, position: 'sales_rep', business_unit_id: businessUnitId },
+    context: delegateCtx(organizationId),
+  });
+
+describe('DelegatedAdminGate — a scope anchor never crosses an organization', () => {
+  it('ground truth: two organizations each hold a unit named `sales`, and org B sorts first', async () => {
+    const engine = await bootEngine();
+    const b = await seedOrganization(engine, ORG_B, '0');
+    const a = await seedOrganization(engine, ORG_A, 'a');
+
+    // Read past every scope: the population the by-name read chose from.
+    const driver: any = (engine as any).getDriver('sys_business_unit');
+    const raw = await driver.knex('sys_business_unit').where({ name: 'sales' }).orderBy('id', 'asc');
+    expect(raw.map((r: any) => r.id)).toEqual([b.sales, a.sales]);
+    expect(raw.map((r: any) => r.organization_id)).toEqual([ORG_B, ORG_A]);
+  });
+
+  it('the org A delegate KEEPS its own subtree — a write inside org A `sales` is approved', async () => {
+    const engine = await bootEngine();
+    await seedOrganization(engine, ORG_B, '0');
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = gateOn(engine);
+
+    await expect(assignInto(gate, ORG_A, a.salesEast, a.user)).resolves.toBeUndefined();
+  });
+
+  it('the org A delegate cannot reach org B — a write anchored in the other organization is REFUSED', async () => {
+    const engine = await bootEngine();
+    const b = await seedOrganization(engine, ORG_B, '0');
+    await seedOrganization(engine, ORG_A, 'a');
+    const gate = gateOn(engine);
+
+    await expect(assignInto(gate, ORG_A, b.salesEast, b.user)).rejects.toThrow(
+      /outside the delegated subtree/,
+    );
+  });
+
+  it('describeDelegableScope names the caller\'s own units and NOTHING of the other organization', async () => {
+    const engine = await bootEngine();
+    const b = await seedOrganization(engine, ORG_B, '0');
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = gateOn(engine);
+
+    const report = await gate.describeDelegableScope(DELEGATE_SETS, delegateCtx(ORG_A));
+
+    expect([...report.placeableBusinessUnitIds].sort()).toEqual([a.sales, a.salesEast].sort());
+    expect(report.scopes).toHaveLength(1);
+    expect([...report.scopes[0].businessUnitIds].sort()).toEqual([a.sales, a.salesEast].sort());
+    // The refusal, stated as absence: no org B id appears anywhere in the report.
+    const serialized = JSON.stringify(report);
+    expect(serialized).not.toContain(b.sales);
+    expect(serialized).not.toContain(b.salesEast);
+  });
+
+  it('a tenant admin is unconstrained INSIDE its organization, never across organizations', async () => {
+    const engine = await bootEngine();
+    const b = await seedOrganization(engine, ORG_B, '0');
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = new DelegatedAdminGate({
+      ql: engine,
+      resolveSets: async () => [
+        { name: 'admin_full', objects: { '*': { allowRead: true, modifyAllRecords: true } } },
+      ] as unknown as PermissionSet[],
+    });
+
+    const report = await gate.describeDelegableScope([
+      { name: 'admin_full', objects: { '*': { allowRead: true, modifyAllRecords: true } } },
+    ] as unknown as PermissionSet[], { userId: 'usr_admin', tenantId: ORG_A });
+
+    expect(report.isTenantAdmin).toBe(true);
+    expect([...report.placeableBusinessUnitIds].sort()).toEqual([a.sales, a.salesEast].sort());
+    expect(report.placeableBusinessUnitIds).not.toContain(b.sales);
+  });
+
+  // ── Controls: the assertions above must be able to fail, and the
+  //    organization-less surface must be untouched. ───────────────────────
+  it('control (dark) — one organization holding `sales` resolves it, and the in-org write is approved', async () => {
+    const engine = await bootEngine();
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = gateOn(engine);
+
+    const report = await gate.describeDelegableScope(DELEGATE_SETS, delegateCtx(ORG_A));
+    expect([...report.placeableBusinessUnitIds].sort()).toEqual([a.sales, a.salesEast].sort());
+    await expect(assignInto(gate, ORG_A, a.salesEast, a.user)).resolves.toBeUndefined();
+  });
+
+  it('control (firing) — an anchor naming no unit in the caller\'s organization approves nothing', async () => {
+    const engine = await bootEngine();
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = new DelegatedAdminGate({
+      ql: engine,
+      resolveSets: async (context: any) =>
+        context?.principal === 'delegate'
+          ? ([{ name: 'sales_admin', objects: {}, adminScope: { ...SALES_SCOPE, businessUnit: 'no_such_unit' } }] as unknown as PermissionSet[])
+          : [],
+    });
+
+    await expect(assignInto(gate, ORG_A, a.salesEast, a.user)).rejects.toThrow(
+      /outside the delegated subtree/,
+    );
+  });
+
+  it('a `single`-posture caller (no organization in context) keeps the by-name answer', async () => {
+    const engine = await bootEngine();
+    const a = await seedOrganization(engine, ORG_A, 'a');
+    const gate = gateOn(engine);
+
+    const report = await gate.describeDelegableScope(DELEGATE_SETS, {
+      principal: 'delegate',
+      userId: 'usr_delegate',
+    });
+    expect([...report.placeableBusinessUnitIds].sort()).toEqual([a.sales, a.salesEast].sort());
+  });
+});