@@ -0,0 +1,11 @@
+---
+'@objectstack/plugin-security': patch
+---
+
+fix(plugin-security): under the `group` posture, a tenant-scoped insert from a session with no active organization is refused 403 naming the missing organization, as `isolated` already answered, instead of a 500
+
+Clause-②: no (no accept set moves: the insert was refused before and is refused now, with the ADR-0123 D2 answer in place of an internal error)
+
+- **Before.** On `group` (any union-scope posture), a member of an organization whose session had no active organization got `500 ERR_SYSTEM_WRITE_ORGANIZATION_REQUIRED` for a create on a tenant-scoped object, logged as an unhandled REST error.
+- **After.** That create gets `403 PERMISSION_DENIED` with the message `isolated` gives the same session, which names the missing active organization and tells the user to join or select one.
+- **Unchanged.** Nothing was written before and nothing is written now. The refusal judges the row as it is about to be stored, the same row the engine's own organization check reads, so it covers exactly the inserts that answered 500 and no insert that was admitted. Reads still span the member's organizations. Updates and deletes of rows the membership wall admits, inserts from a session with an active organization, system contexts, a platform operator on a posture-permitting object, the delegator's leg, and every `isolated` and `single` answer are as before.
@@ -0,0 +1,245 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [ADR-0123 D2 · ADR-0105 D2/D5] A tenant-scoped INSERT from a session with no
+ * active organization gets the ADR-0123 D2 refusal under EVERY walled posture,
+ * `group` included — measured on the real stack (ObjectQL + SqlDriver +
+ * SecurityPlugin), never a 500 and never a row.
+ *
+ * ## The rule
+ *
+ * Under `group` the caller's membership set (`accessible_org_ids`) bounds what
+ * it may READ (ADR-0105 D2), and a new row lands in the ACTIVE organization,
+ * the default write target the engine stamps from `tenantId` (ADR-0105 D5). A
+ * session with no active organization therefore has no organization to place a
+ * new row in. ADR-0123 D2 answers that state with `403 PERMISSION_DENIED`, a
+ * message naming the missing active organization, and `isolated` always did.
+ *
+ * `group` used to let that insert through the Layer 0 wall, whose scope test
+ * reads the membership set there, and the engine then refused the row as an
+ * organization-less SYSTEM write (`ERR_SYSTEM_WRITE_ORGANIZATION_REQUIRED`,
+ * status 500). Nothing was stored, so it failed closed; the defect was the
+ * answer. The wall now judges the stored image in that case and refuses it
+ * with the same D2 answer, before the engine is reached.
+ *
+ * ## What this file pins
+ *
+ * - `group`: refused with the D2 answer, and no row is stored;
+ * - `isolated` (control, unchanged): the same context gets the same answer —
+ *   the two outcomes are compared whole, so "exactly what `isolated` answers"
+ *   is measured rather than restated;
+ * - `group` (control): the same member WITH an active organization is
+ *   admitted, and the row lands in that organization;
+ * - `group` (control): a session with NO membership at all keeps the D2
+ *   refusal it already had;
+ * - `group` (control): reads with no active organization still span the
+ *   membership set — the posture's design, untouched.
+ */
+
+import { describe, it, expect, afterEach, vi } from 'vitest';
+import { ObjectQL } from '@objectstack/objectql';
+import { SqlDriver } from '@objectstack/driver-sql';
+import type { PermissionSet } from '@objectstack/spec/security';
+import { SecurityPlugin } from './security-plugin.js';
+
+/** Two organizations the member belongs to, and one it does not. */
+const OWN_ORG = 'org_a';
+const SISTER_ORG = 'org_c';
+const OTHER_ORG = 'org_b';
+
+/** A public tenant object: the platform injects `organization_id`, so Layer 0 walls it. */
+const OBJECTS = [
+  {
+    name: 'qa_task',
+    label: 'Task',
+    fields: {
+      id: { name: 'id', type: 'text', primaryKey: true },
+      name: { name: 'name', type: 'text' },
+    },
+  },
+];
+
+/** Plain CRUD and no row-level policy — Layer 0 is the only enforcer under test. */
+const MEMBER: PermissionSet = {
+  name: 'member_default',
+  label: 'Member',
+  objects: { '*': { allowRead: true, allowCreate: true, allowEdit: true, allowDelete: true } },
+} as unknown as PermissionSet;
+
+const SYS_CTX = { isSystem: true, userId: 'usr_system', tenantId: OWN_ORG };
+
+/**
+ * The subject: an authenticated member of two organizations whose session has
+ * no active organization. ONE context for every posture, so the `isolated`
+ * control differs from the `group` case in the posture alone.
+ */
+const NO_ACTIVE_ORG_CTX = {
+  userId: 'usr_a',
+  positions: [],
+  permissions: [],
+  posture: 'MEMBER',
+  accessible_org_ids: [OWN_ORG, SISTER_ORG],
+};
+/** The same member one `set-active` later — the single-fact control. */
+const ACTIVE_ORG_CTX = { ...NO_ACTIVE_ORG_CTX, tenantId: OWN_ORG };
+/** A session that belongs to no organization at all. */
+const NO_MEMBERSHIP_CTX = { userId: 'usr_z', positions: [], permissions: [], posture: 'MEMBER', accessible_org_ids: [] };
+
+type Posture = 'isolated' | 'group';
+
+const engines: ObjectQL[] = [];
+afterEach(async () => {
+  while (engines.length) {
+    try { await engines.pop()?.destroy(); } catch { /* noop */ }
+  }
+});
+
+interface Booted {
+  engine: ObjectQL;
+  /** The table read straight off the driver, past every scope. */
+  table: () => Promise<Array<Record<string, unknown>>>;
+}
+
+const SEEDED = [
+  { id: 'r1', name: 'own', organization_id: OWN_ORG },
+  { id: 'r2', name: 'other', organization_id: OTHER_ORG },
+  { id: 'r3', name: 'sister', organization_id: SISTER_ORG },
+];
+
+async function boot(posture: Posture): Promise<Booted> {
+  const engine = new ObjectQL();
+  engine.registerDriver(
+    new SqlDriver({ client: 'better-sqlite3', connection: { filename: ':memory:' }, useNullAsDefault: true } as never) as never,
+    true,
+  );
+  await engine.init();
+  engine.registerApp({
+    id: 'com.objectstack.qa.no-active-organization-insert-union-scope',
+    name: 'No active organization, union-scope posture',
+    version: '1.0.0',
+    type: 'plugin',
+    scope: 'system',
+    objects: OBJECTS,
+  } as never);
+  await engine.syncSchemas();
+  engines.push(engine);
+
+  // The posture the package's other real-stack posture pins boot: the
+  // `org-scoping` sentinel activates the wall and `tenancy` names the posture,
+  // which SecurityPlugin also hands the engine (`setTenancyPostureProvider`).
+  const services: Record<string, unknown> = {
+    manifest: { register: vi.fn() },
+    objectql: engine,
+    metadata: {
+      get: async (_type: string, name: string) => engine.getSchema(name) ?? null,
+      list: async () => [MEMBER],
+    },
+    'org-scoping': { name: 'com.objectstack.org-scoping' },
+    tenancy: { posture },
+  };
+  const ctx = {
+    logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
+    registerService: vi.fn(),
+    getService: (name: string) => {
+      if (!(name in services)) throw new Error(`service not registered: ${name}`);
+      return services[name];
+    },
+  };
+  const plugin = new SecurityPlugin({ fallbackPermissionSet: 'member_default' });
+  await plugin.init(ctx as never);
+  await plugin.start(ctx as never);
+  vi.spyOn((engine as unknown as { logger: { warn: () => void } }).logger, 'warn').mockImplementation(() => undefined);
+
+  await engine.insert('qa_task', SEEDED.map((r) => ({ ...r })), { context: SYS_CTX } as never);
+
+  const table = async () => {
+    const driver = (engine as unknown as { getDriver(o: string): { knex: unknown } }).getDriver('qa_task');
+    const knex = driver.knex as (t: string) => { select: (...c: string[]) => Promise<Array<Record<string, unknown>>> };
+    const rows = await knex('qa_task').select('id', 'name', 'organization_id');
+    return [...rows].sort((a, b) => String(a.id).localeCompare(String(b.id)));
+  };
+  return { engine, table };
+}
+
+interface Outcome { ok: boolean; code?: string; status?: number; message?: string }
+
+const attempt = async (run: () => Promise<unknown>): Promise<Outcome> => {
+  try {
+    await run();
+    return { ok: true };
+  } catch (e) {
+    const err = e as { code?: string; statusCode?: number; status?: number; message?: string };
+    return { ok: false, code: err.code, status: err.statusCode ?? err.status, message: String(err.message ?? e) };
+  }
+};
+
+const create = (b: Booted, data: unknown, context: object) =>
+  b.engine.insert('qa_task', data as never, { context } as never);
+
+/** The ADR-0123 D2 answer on the ADR-0112 envelope: `code` + `status`, then the D4 naming. */
+const expectNoActiveOrganizationRefusal = (outcome: Outcome) => {
+  expect(outcome.ok, 'expected a refusal, got a completed write').toBe(false);
+  expect(outcome.code, 'ADR-0112 error code').toBe('PERMISSION_DENIED');
+  expect(outcome.status, 'ADR-0112 HTTP status').toBe(403);
+  // ADR-0123 D4: the refusal names what is missing, so it cannot be mistaken
+  // for an ordinary permission denial.
+  expect(outcome.message).toMatch(/no active organization/i);
+};
+
+describe('[ADR-0123 D2] a tenant-scoped insert from a session with no active organization — real stack', () => {
+  it('group: is refused 403 PERMISSION_DENIED naming the missing active organization, and stores nothing', async () => {
+    const b = await boot('group');
+
+    const outcome = await attempt(() => create(b, { id: 'n1', name: 'new' }, NO_ACTIVE_ORG_CTX));
+
+    expectNoActiveOrganizationRefusal(outcome);
+    expect(await b.table(), 'no row stored, NULL-organization or otherwise').toEqual(SEEDED);
+  });
+
+  it('group: a bulk insert is refused as a whole, and stores nothing', async () => {
+    const b = await boot('group');
+
+    const outcome = await attempt(() => create(b, [{ id: 'n1', name: 'a' }, { id: 'n2', name: 'b' }], NO_ACTIVE_ORG_CTX));
+
+    expectNoActiveOrganizationRefusal(outcome);
+    expect(await b.table()).toEqual(SEEDED);
+  });
+
+  it('isolated (control, unchanged): the same context gets the same refusal, and group answers exactly what isolated answers', async () => {
+    const isolated = await boot('isolated');
+    const group = await boot('group');
+
+    const isolatedOutcome = await attempt(() => create(isolated, { id: 'n1', name: 'new' }, NO_ACTIVE_ORG_CTX));
+    const groupOutcome = await attempt(() => create(group, { id: 'n1', name: 'new' }, NO_ACTIVE_ORG_CTX));
+
+    expectNoActiveOrganizationRefusal(isolatedOutcome);
+    expect(await isolated.table()).toEqual(SEEDED);
+    expect(groupOutcome, 'group answers exactly what isolated answers').toEqual(isolatedOutcome);
+  });
+
+  it('group (control): the same member WITH an active organization is admitted, and the row lands in it', async () => {
+    const b = await boot('group');
+
+    const outcome = await attempt(() => create(b, { id: 'n1', name: 'new' }, ACTIVE_ORG_CTX));
+
+    expect(outcome, 'expected the write to be admitted').toEqual({ ok: true });
+    expect(await b.table()).toEqual([{ id: 'n1', name: 'new', organization_id: OWN_ORG }, ...SEEDED]);
+  });
+
+  it('group (control): a session with no membership at all keeps the D2 refusal', async () => {
+    const b = await boot('group');
+
+    const outcome = await attempt(() => create(b, { id: 'n1', name: 'new' }, NO_MEMBERSHIP_CTX));
+
+    expectNoActiveOrganizationRefusal(outcome);
+    expect(await b.table()).toEqual(SEEDED);
+  });
+
+  it('group (control): reads with no active organization still span the membership set', async () => {
+    const b = await boot('group');
+
+    const rows = (await b.engine.find('qa_task', { context: NO_ACTIVE_ORG_CTX } as never)) as Array<Record<string, unknown>>;
+
+    expect(rows.map((r) => r.id).sort()).toEqual(['r1', 'r3']);
+  });
+});
@@ -38,9 +38,9 @@
  *
  * Every control below is paired with the case it controls: for each exemption
  * (system context, platform operator, non-tenant object, `single` posture, a
- * non-empty `group` membership set) there is a sibling case differing in that
- * one fact where the refusal DOES fire. A file of controls alone would pass on
- * the pre-fix build.
+ * `group` membership set WITH an active organization) there is a sibling case
+ * differing in that one fact where the refusal DOES fire. A file of controls
+ * alone would pass on the pre-fix build.
  */
 
 import { describe, it, expect, vi } from 'vitest';
@@ -289,15 +289,28 @@ describe('[ADR-0123 D2] tenant-scoped WRITES with no active organization are ref
       expectConformingRefusal(err);
     });
 
-    it('CONTROL: a NON-EMPTY membership set lands, even with no active organization', async () => {
-      // The half a `tenantId`-only test would get wrong: under `group` the
-      // membership set IS the scope, so this caller is fully scoped despite
-      // carrying no active organization.
+    it('a NON-EMPTY membership set with NO active organization: an insert has nowhere to land, and is refused the same way', async () => {
+      // The membership set is the READ scope under `group`, so this caller
+      // passes the scope pre-test; a new row still lands in the ACTIVE
+      // organization (ADR-0105 D5), and there is none. The stored image is
+      // judged — the terminal here runs the seam on the rows as sent. The
+      // real-stack twin, with the engine and a driver, is
+      // `no-active-organization-insert-union-scope.test.ts`.
       const h = await boot({ posture: 'group' });
-      await h.run({
+      const err = await refusalFrom(h.run, {
         object: 'task', operation: 'insert', data: { name: 'A' },
         context: { ...ORG_LESS, accessible_org_ids: ['org-1', 'org-2'] },
       });
+      expectConformingRefusal(err);
+    });
+
+    it('CONTROL: the same membership set WITH an active organization lands', async () => {
+      // The single-fact control for the case above: only `tenantId` differs.
+      const h = await boot({ posture: 'group' });
+      await h.run({
+        object: 'task', operation: 'insert', data: { name: 'A' },
+        context: { ...ORG_BOUND, accessible_org_ids: ['org-1', 'org-2'] },
+      });
     });
   });