@@ -0,0 +1,12 @@
+---
+'@objectstack/core': patch
+---
+
+perf(core): an administrator whose `admin_full_access` grant belongs to the Default Organization no longer pays a `sys_organization` read on every authenticated request
+
+Clause-②: no (a per-engine memo of an unchanged read: no accept set, standing verdict or served body moves; owes the seat's review of record before the queue, at `CONTRACT_REVIEW_TIER` because it is the platform-standing anchor)
+
+- **The Default Organization is read once per engine, not once per request.** Under `single`, `resolveUserAuthzGrants` asks for the Default Organization whenever the principal holds an organization-owned `admin_full_access` grant: one `sys_organization` read, or two when the only organization is not slugged `default`. The answer is now kept per engine across requests. On a booted composition the warm `get-session` costs 8 statements and a data read 10, the same as for an organization-less grant. Before, it cost 9 and 11, or 10 and 12.
+- **What retires it.** Any `sys_organization` write through the engine (insert, update, delete), observed after it settles. With the `authz.invalidated` bridge attached (the grants cache on, `OS_AUTHZ_GRANTS_CACHE_TTL_MS` above 0, and a cross-process cluster driver), a peer replica's write arrives as a `remote` epoch bump and retires it; every other non-`write` bump (`metadata`, `manual`) retires it too. A 30-second bound covers what no seam sees: a peer's write with no bridge attached, which on the shipped default (the grants cache off) is every peer's write, so there the bound is the only cover for it; a write that started before the engine's observer registered; and a write inside a transaction that has not committed yet. A Default Organization that is deleted and recreated, or a `default` slug moved to another organization, is read again on the next request.
+- **A failed read is not kept.** A read that fails with the authorization store unavailable propagates as before, and the next request reads again. "No Default Organization" (no organization, or several and none `default`) is a real answer and is kept.
+- **Unchanged:** the two reads, their filters and limits, and the platform-standing predicate the answer feeds. An engine without the write epoch and `registerMiddleware`, or a registry that does not hold `sys_organization`, keeps reading every time.
@@ -0,0 +1,310 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#24523] The Default Organization answer is memoised per engine across
+ * requests, and retired by a `sys_organization` write through the engine's
+ * write seam, by a non-`write` epoch bump, and by the residual TTL.
+ *
+ * Every case drives `resolveUserAuthzGrants` — the one caller — on a recording
+ * double that carries the two engine seams the memo requires, shaped as the
+ * engine's own (the same shape `resolve-localization-cache.test.ts` drives the
+ * leg-5 seam with): the write epoch, bumped with `'write'` when a write STARTS,
+ * and a middleware chain each write SNAPSHOTS when it starts.
+ *
+ * What each case reads: the `sys_organization` reads a resolution issued
+ * (zero on a memo hit), and the platform standing the answer feeds. ⛔ The
+ * reads themselves — `{ slug: 'default' }` limit 1, then `{}` limit 2 — are
+ * asserted byte-for-byte wherever they are issued: only how often they run
+ * moves.
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { ADMIN_FULL_ACCESS } from '@objectstack/spec';
+
+import { resetPlatformAdminEmailMemo } from './platform-admin.js';
+import { resolveUserAuthzGrants } from './resolve-authz-context.js';
+import { makeRecordingQl } from './__tests__/resolve-authz-context.batch-equivalence.testkit.js';
+
+const NOW = Date.parse('2026-10-19T00:00:00.000Z');
+const ENVS = ['OS_TENANCY_POSTURE', 'OS_MULTI_ORG_ENABLED', 'OS_PLATFORM_OWNER_EMAIL', 'OS_AUTHZ_GRANTS_CACHE_TTL_MS'] as const;
+
+let ambient: Record<string, string | undefined> = {};
+beforeEach(() => {
+  ambient = Object.fromEntries(ENVS.map((k) => [k, process.env[k]]));
+  // `single`, no configured administrator, the grants cache at its default (off).
+  for (const k of ENVS) delete process.env[k];
+  resetPlatformAdminEmailMemo();
+});
+afterEach(() => {
+  vi.restoreAllMocks();
+  for (const k of ENVS) {
+    if (ambient[k] === undefined) delete process.env[k];
+    else process.env[k] = ambient[k];
+  }
+  resetPlatformAdminEmailMemo();
+});
+
+type Middleware = (ctx: { object: string; operation: string }, next: () => Promise<void>) => Promise<void>;
+
+const BY_SLUG = { object: 'sys_organization', where: { slug: 'default' }, limit: 1, isSystem: true };
+const SOLE = { object: 'sys_organization', where: {}, limit: 2, isSystem: true };
+
+/**
+ * The administrator's tables: one `admin_full_access` grant owned by
+ * `grantOrganization`, and the organizations given.
+ */
+function tablesOf(grantOrganization: string, organizations: Array<Record<string, unknown>>) {
+  return {
+    sys_user: [{ id: 'usr_1', email: 'admin@example.com' }],
+    sys_member: [],
+    sys_user_position: [],
+    sys_user_permission_set: [
+      { id: 'ups_1', user_id: 'usr_1', permission_set: ADMIN_FULL_ACCESS, organization_id: grantOrganization },
+    ],
+    sys_permission_set: [{ id: 'pst_1', name: ADMIN_FULL_ACCESS, active: true }],
+    sys_organization: organizations,
+  } as Record<string, Array<Record<string, unknown>>>;
+}
+
+/**
+ * {@link makeRecordingQl} with the engine's write seams. `write(object,
+ * operation, apply)` is one engine write: the epoch first, then the chain as
+ * it stood when the write started, `apply` as its driver step. `pause` holds a
+ * write between its start and its driver step, for the in-flight cases.
+ */
+function makeEngineQl(tables: Record<string, Array<Record<string, unknown>>>, seams = true) {
+  const ql = makeRecordingQl(tables) as ReturnType<typeof makeRecordingQl> & Record<string, any>;
+  const listeners = new Set<(epoch: number, reason: string) => void>();
+  const middlewares: Middleware[] = [];
+  let epoch = 0;
+  const writeEpoch = {
+    get current() {
+      return epoch;
+    },
+    bump(reason: string) {
+      epoch += 1;
+      for (const l of [...listeners]) l(epoch, reason);
+      return epoch;
+    },
+    subscribe(l: (e: number, r: string) => void) {
+      listeners.add(l);
+      return () => listeners.delete(l);
+    },
+  };
+  if (seams) {
+    ql.writeEpoch = writeEpoch;
+    ql.registerMiddleware = (fn: Middleware) => {
+      middlewares.push(fn);
+    };
+  }
+  const write = async (
+    object: string,
+    operation: 'insert' | 'update' | 'delete',
+    apply: () => void,
+    pause?: Promise<void>,
+  ): Promise<void> => {
+    writeEpoch.bump('write');
+    const chain = [...middlewares];
+    let i = 0;
+    const next = async (): Promise<void> => {
+      if (i < chain.length) return chain[i++]({ object, operation }, next);
+      if (pause) await pause;
+      apply();
+    };
+    await next();
+  };
+  const organizationReads = () => ql.calls.filter((c) => c.object === 'sys_organization');
+  /** The `sys_organization` reads one resolution issued, and its platform standing. */
+  const resolve = async () => {
+    const before = organizationReads().length;
+    const grants = await resolveUserAuthzGrants(ql, 'usr_1', { nowMs: NOW, seedEmail: 'admin@example.com' });
+    return { reads: organizationReads().slice(before), standing: grants.positions.includes('platform_admin') };
+  };
+  return { ql, write, writeEpoch, middlewares, resolve };
+}
+
+describe('[#24523] the Default Organization answer is read once per engine', () => {
+  it('⭐ slugged `default`: the first resolution reads it, the next ones do not', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('⭐ the only organization, slugged otherwise: two reads once, then none', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'acme' }]));
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG, SOLE], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('`undefined` is a real answer and is memoised: several organizations, none `default`', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'acme' }, { id: 'org_b', slug: 'beta' }]));
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG, SOLE], standing: false });
+    expect(await e.resolve()).toEqual({ reads: [], standing: false });
+    // …and an organization write retires it like any other answer.
+    await e.write('sys_organization', 'update', () => {});
+    expect((await e.resolve()).reads).toEqual([BY_SLUG, SOLE]);
+  });
+
+  it('CONTROL — an engine without the write seams memoises nothing: every resolution reads, as before', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]), false);
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+  });
+
+  it('CONTROL — an organization-less grant never reads it, memo or not', async () => {
+    const e = makeEngineQl(tablesOf('', [{ id: 'org_a', slug: 'default' }]));
+    // The grant's organization is blank: the legacy organization-less spelling.
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+    expect(e.middlewares).toHaveLength(0);
+  });
+});
+
+describe('[#24523 / #21868] a sys_organization write through the engine retires the answer', () => {
+  it('⭐ the Default Organization deleted and recreated: the next resolution reads the new id', async () => {
+    const tables = tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]);
+    const e = makeEngineQl(tables);
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+
+    await e.write('sys_organization', 'delete', () => {
+      tables.sys_organization.splice(0);
+    });
+    await e.write('sys_organization', 'insert', () => {
+      tables.sys_organization.push({ id: 'org_b', slug: 'default' });
+    });
+    // The first-user promotion's grant now belongs to the new organization.
+    tables.sys_user_permission_set[0].organization_id = 'org_b';
+
+    // A memo still answering `org_a` would withhold standing from `org_b`'s grant.
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('⭐ a slug change that moves `default` to another organization: the old organization\'s grant stops anchoring', async () => {
+    const tables = tablesOf('org_a', [{ id: 'org_a', slug: 'default' }, { id: 'org_b', slug: 'beta' }]);
+    const e = makeEngineQl(tables);
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+
+    await e.write('sys_organization', 'update', () => {
+      tables.sys_organization[0].slug = 'alpha';
+    });
+    await e.write('sys_organization', 'update', () => {
+      tables.sys_organization[1].slug = 'default';
+    });
+    // The GRANTING direction: a memo still answering `org_a` would keep
+    // conferring standing on `org_a`'s grant.
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: false });
+
+    tables.sys_user_permission_set[0].organization_id = 'org_b';
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('a write to another object — a watched grants table included — does not retire it', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    await e.resolve();
+    await e.write('sys_user_permission_set', 'update', () => {});
+    await e.write('sys_session', 'update', () => {});
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('the `remote` and `metadata` epoch bumps retire it; a bare `write` bump does not', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    await e.resolve();
+    e.writeEpoch.bump('write');
+    expect((await e.resolve()).reads).toEqual([]);
+    e.writeEpoch.bump('remote');
+    expect((await e.resolve()).reads).toEqual([BY_SLUG]);
+    e.writeEpoch.bump('metadata');
+    expect((await e.resolve()).reads).toEqual([BY_SLUG]);
+    expect((await e.resolve()).reads).toEqual([]);
+  });
+
+  it('a write that lands WHILE the read is in flight leaves that answer dead on arrival', async () => {
+    const tables = tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]);
+    const e = makeEngineQl(tables);
+    // Register the observer first (one resolution), then retire it so the next one reads.
+    await e.resolve();
+    e.writeEpoch.bump('manual');
+    const find = e.ql.find.bind(e.ql);
+    let landed = false;
+    e.ql.find = async (object: string, opts: any) => {
+      const rows = await find(object, opts);
+      if (object === 'sys_organization' && !landed) {
+        landed = true;
+        // The rows above are the pre-write snapshot; the write settles before the resolution does.
+        await e.write('sys_organization', 'update', () => {
+          tables.sys_organization[0].slug = 'gone';
+        });
+      }
+      return rows;
+    };
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    // Not served from the entry that read was stored under.
+    expect((await e.resolve()).reads).toEqual([BY_SLUG, SOLE]);
+  });
+
+  it('the TTL is the residual bound: an answer older than 30 s is read again', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    const clock = vi.spyOn(Date, 'now').mockReturnValue(NOW);
+    await e.resolve();
+    clock.mockReturnValue(NOW + 29_999);
+    expect((await e.resolve()).reads).toEqual([]);
+    clock.mockReturnValue(NOW + 30_001);
+    expect((await e.resolve()).reads).toEqual([BY_SLUG]);
+  });
+
+  it('MEASURED — a write that STARTED before the observer registered is not seen; the TTL bounds it', async () => {
+    const tables = tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]);
+    const e = makeEngineQl(tables);
+    const clock = vi.spyOn(Date, 'now').mockReturnValue(NOW);
+    let release!: () => void;
+    const pause = new Promise<void>((r) => {
+      release = r;
+    });
+    // The write starts with an empty chain: no observer is registered yet.
+    const inFlight = e.write('sys_organization', 'update', () => {
+      tables.sys_organization[0].slug = 'alpha';
+    }, pause);
+    // The first resolution registers the observer and reads the pre-write row.
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    release();
+    await inFlight;
+    // The write landed unobserved: the answer stands, stale, until the TTL.
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+    clock.mockReturnValue(NOW + 30_001);
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG, SOLE], standing: true });
+  });
+});
+
+describe('[#24523] ⛔ an outage is not an answer', () => {
+  it('⭐ a failed read memoises nothing: it propagates, and the next resolution reads again', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    const find = e.ql.find.bind(e.ql);
+    let down = true;
+    e.ql.find = async (object: string, opts: any) => {
+      if (object === 'sys_organization' && down) {
+        await find(object, opts); // recorded as issued
+        throw new Error('connect ECONNREFUSED 127.0.0.1:5432');
+      }
+      return find(object, opts);
+    };
+    const refused = await resolveUserAuthzGrants(e.ql, 'usr_1', { nowMs: NOW, seedEmail: 'admin@example.com' })
+      .then(() => undefined, (err: unknown) => err as { code?: unknown; status?: unknown });
+    expect(refused).toMatchObject({ code: 'SERVICE_UNAVAILABLE', status: 503 });
+
+    down = false;
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+    expect(await e.resolve()).toEqual({ reads: [], standing: true });
+  });
+
+  it('a registry that does not hold sys_organization: no read, nothing wired, nothing memoised', async () => {
+    const e = makeEngineQl(tablesOf('org_a', [{ id: 'org_a', slug: 'default' }]));
+    let registered = false;
+    e.ql.registry = { getObject: (name: string) => (name === 'sys_organization' ? registered : true) };
+    expect(await e.resolve()).toEqual({ reads: [], standing: false });
+    expect(e.middlewares).toHaveLength(0);
+    // Registered later in the same boot: read at once, not answered from a verdict.
+    registered = true;
+    expect(await e.resolve()).toEqual({ reads: [BY_SLUG], standing: true });
+  });
+});