@@ -0,0 +1,22 @@
+---
+'@objectstack/verify': minor
+---
+
+verify: let `bootStack` be told which package `multiTenant: true` resolves, so the
+`declared-unresolvable` control can name a subject the workspace can never supply
+
+`BootOptions` gains an optional `organizationsPackage`. It defaults to
+`@objectstack/organizations` and production callers never pass it — the
+operator-facing error still names that package literally, because in every
+production boot it is the subject. Only the specifier moves.
+
+Why it exists: a fixture whose whole content is "this host root DECLARED the
+package and does not have it" cannot state the second half with a name the
+workspace owns. Since ADR-0132 the multi-org runtime is a tracked workspace
+package, pnpm's hoisted store carries it, and a `pnpm exec`-launched runner
+exports a `NODE_PATH` that reaches that store — so such a fixture resolved the
+package out of the ambient workspace the moment it had been built, and its
+verdict became a function of an unrelated package's build state rather than of
+its own directory. The harness's own host-resolution control now hands in a
+`@fixture/*` name and proves the absence instead of assuming it, the repair
+already landed for `packages/qa/dogfood` and `packages/types`.
@@ -27,13 +27,53 @@
  * that is the whole point), registering the same `org-scoping` service and
  * posture entitlement the real one does. What is under test here is
  * RESOLUTION, not the enterprise semantics.
+ *
+ * ── #17911 — why ONE case below drives a `@fixture/*` subject ────────────────
+ *
+ * The CONTROL's whole content is "this host root DECLARED it and does not have
+ * it". Until ADR-0132 / #16215 that came free: `@objectstack/organizations` was
+ * cloud-private, so a temp host that declared it and did not install it was
+ * unresolvable by construction. It is a tracked workspace package now, pnpm's
+ * hoisted store carries it, and vitest's own `pnpm exec` bin shim exports a
+ * `NODE_PATH` that reaches that store — so the package RESOLVED, the wall came
+ * up, and boot was refused several steps later by the membership-policy gate
+ * whose message even says "This is NOT … a missing package". The CONTROL never
+ * reached the wording it exists to pin: red on any tree with a full local
+ * build, green on CI, and proving nothing in either state.
+ *
+ * So that one case hands in a name this workspace can never contain and the
+ * PREMISE block below PROVES the absence instead of assuming it — the repair
+ * #16539 (dogfood) and #16552 (`packages/types/src/node.test.ts`) landed, for
+ * the reason those cards state verbatim: no workspace name is safe from
+ * becoming one.
+ *
+ * ⛔ The other four cases deliberately stay on the REAL subject, and that is
+ * what keeps `ORGANIZATIONS_PKG` pinned as `bootStack`'s default: each of them
+ * is decided by something the ambient workspace cannot supply — an app-local
+ * `node_modules` copy, which wins over `NODE_PATH`, or the UNDECLARED arm,
+ * whose fallback is this module's own ESM `import()` and Node's ESM resolver
+ * does not consult `NODE_PATH` at all. Measured in both build states (#17911).
  */
 
 import { describe, it, expect, beforeAll, afterAll, afterEach } from 'vitest';
 import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
-import { bootStack } from './harness.js';
+import { createHostRequire } from '@objectstack/types/node';
+import { bootStack, ORGANIZATIONS_PKG } from './harness.js';
+
+/**
+ * The subject the `declared-unresolvable` CONTROL is built around: modelled on
+ * the real enterprise package, fixture-only in NAME.
+ *
+ * ⚠️ #17911 — it must stay a `@fixture/*` name. A name this workspace owns
+ * cannot state "this host root does not have it", because the hoisted store and
+ * the launcher's `NODE_PATH` answer that question instead of the fixture; and no
+ * workspace name is safe from becoming one (`@objectstack/organizations` was
+ * cloud-private when this case was written). Only a name the workspace can never
+ * contain is, and the PREMISE cases at the bottom prove this one still is not.
+ */
+const FIXTURE_ORGANIZATIONS = '@fixture/host-organizations';
 
 /**
  * Stand-in for `@objectstack/organizations`. Mirrors the real plugin's
@@ -92,14 +132,30 @@ let appDeclaredNoLoadableEntry: string;
  * untouched by #14270, so this case must render byte-identically before and
  * after — that is what makes the third arm's flip a measurement rather than a
  * rewrite that moved everything.
+ *
+ * ⚠️ #17911 — "NOT installed" is a property of THIS directory, and only a
+ * subject the workspace can never supply keeps it one. See
+ * {@link FIXTURE_ORGANIZATIONS}.
  */
 let appDeclaredNotInstalled: string;
+/**
+ * #17911 PREMISE leg 1 only — a host that really does install the fixture
+ * subject. Without it, a subject that exists NOWHERE (a typo, a deleted scope)
+ * would satisfy the absence leg and the CONTROL would be vacuous.
+ */
+let appFixtureInstalled: string;
 
 function writeApp(
   prefix: string,
-  opts: { withOrganizations: boolean; declare?: boolean; typesOnly?: boolean },
+  opts: { withOrganizations: boolean; declare?: boolean; typesOnly?: boolean; pkg?: string },
 ): string {
   const declare = opts.declare ?? opts.withOrganizations;
+  // #17911 — the subject this host declares and/or installs. Defaults to the
+  // real package, which is what four of the five cases need; the CONTROL hands
+  // in `FIXTURE_ORGANIZATIONS` because its verdict is an ABSENCE and only a name
+  // the workspace can never supply keeps that absence a property of this
+  // directory.
+  const pkg = opts.pkg ?? ORGANIZATIONS_PKG;
   const dir = mkdtempSync(join(tmpdir(), prefix));
   writeFileSync(
     join(dir, 'package.json'),
@@ -108,15 +164,16 @@ function writeApp(
         name: 'hostres-fixture',
         private: true,
         type: 'module',
-        ...(declare ? { dependencies: { '@objectstack/organizations': '*' } } : {}),
+        ...(declare ? { dependencies: { [pkg]: '*' } } : {}),
       },
       null,
       2,
     ),
     'utf8',
   );
   if (opts.withOrganizations) {
-    const pkgDir = join(dir, 'node_modules', '@objectstack', 'organizations');
+    // The specifier is a scoped name, so it lands on disk as `<scope>/<name>`.
+    const pkgDir = join(dir, 'node_modules', ...pkg.split('/'));
     mkdirSync(pkgDir, { recursive: true });
     if (opts.typesOnly) {
       // A publish whose `exports` names a `types` target and nothing else: no
@@ -126,7 +183,7 @@ function writeApp(
       writeFileSync(
         join(pkgDir, 'package.json'),
         JSON.stringify({
-          name: '@objectstack/organizations',
+          name: pkg,
           version: '0.0.0-fixture',
           type: 'module',
           exports: { '.': { types: './index.d.ts' } },
@@ -138,7 +195,7 @@ function writeApp(
       writeFileSync(
         join(pkgDir, 'package.json'),
         JSON.stringify({
-          name: '@objectstack/organizations',
+          name: pkg,
           version: '0.0.0-fixture',
           type: 'module',
           main: 'index.js',
@@ -165,6 +222,11 @@ beforeAll(() => {
   appDeclaredNotInstalled = writeApp('os-verify-org-host-not-installed-', {
     withOrganizations: false,
     declare: true,
+    pkg: FIXTURE_ORGANIZATIONS,
+  });
+  appFixtureInstalled = writeApp('os-verify-org-host-fixture-ok-', {
+    withOrganizations: true,
+    pkg: FIXTURE_ORGANIZATIONS,
   });
 });
 
@@ -175,6 +237,7 @@ afterAll(() => {
     appInstalledButUndeclared,
     appDeclaredNoLoadableEntry,
     appDeclaredNotInstalled,
+    appFixtureInstalled,
   ]) {
     if (dir) rmSync(dir, { recursive: true, force: true });
   }
@@ -278,6 +341,14 @@ describe('bootStack multiTenant — host-app package resolution (#4700)', () =>
       // Not a new behaviour, a CONTROL. #14270 rewrote this branch's SHAPE
       // (two-way → three-way); this arm's text has to come out byte-identical,
       // or the third kind's fix moved something that was already right.
+      // ⚠️ #17911 — `organizationsPackage` is why this case can still SAY
+      // "not installed". On the real subject the host's declaration was
+      // honoured, the hoisted store answered the resolve, the wall came up and
+      // boot died several steps later at the membership-policy gate — the
+      // assertion below was never reached, in either direction. The subject is
+      // a `@fixture/*` name the workspace can never contain; the PREMISE block
+      // proves it is absent, and `bootStack`'s DEFAULT subject stays pinned by
+      // the four cases above, which pass no option at all.
       // ⚠️ try/catch rather than `.then(onFulfilled, onRejected)`: `./harness`
       // is imported without its `.js` extension, so under NodeNext the
       // specifier does not resolve and every symbol it names is `any` — which
@@ -290,6 +361,7 @@ describe('bootStack multiTenant — host-app package resolution (#4700)', () =>
         const stack = await bootStack(app as never, {
           multiTenant: true,
           hostRoot: appDeclaredNotInstalled,
+          organizationsPackage: FIXTURE_ORGANIZATIONS,
         });
         await stack.stop();
       } catch (e) {
@@ -342,3 +414,82 @@ describe('bootStack multiTenant — host-app package resolution (#4700)', () =>
     BOOT_TIMEOUT,
   );
 });
+
+/**
+ * #17911 — the premises the CONTROL rests on, asserted instead of assumed.
+ *
+ * Both resolution legs are load-bearing and they fail in opposite directions.
+ * Without leg 1 a subject that exists nowhere at all satisfies leg 2 and the
+ * CONTROL is vacuous; without leg 2 the fixture stops deciding what the host
+ * root has, and the CONTROL silently starts measuring the ambient workspace —
+ * which is exactly how this case broke.
+ */
+describe('PREMISE — the CONTROL subject is host-only (#17911)', () => {
+  it('resolves from a host app that installs it', () => {
+    // Leg 1. A host that really installs the fixture can see it, so
+    // "unresolvable" elsewhere is a statement about the resolver's anchor and
+    // not about a typo or a scope nobody publishes.
+    const fromHost = createHostRequire(appFixtureInstalled).resolve(FIXTURE_ORGANIZATIONS);
+    expect(fromHost).toContain(appFixtureInstalled);
+  });
+
+  it('is absent from every ambient store the runner exposes', () => {
+    // Leg 2, and the guard that would have caught this card. Asserted on the
+    // BARE SPECIFIER, ⛔ never on `/Cannot find module/` alone: a package the
+    // runner CAN see whose entry file merely is not on disk throws
+    // MODULE_NOT_FOUND too, naming `<store>/<pkg>/dist/index.js` instead of the
+    // specifier. That second throw is precisely what kept this CONTROL green
+    // while the property went unguarded — `@objectstack/organizations` was
+    // reachable through the pnpm bin shim's NODE_PATH and simply unbuilt on
+    // CI's task graph. Read as a bare-specifier failure, the premise can no
+    // longer be satisfied by an unbuilt workspace package, in either build
+    // state.
+    expect(() => createHostRequire(appDeclaredNotInstalled).resolve(FIXTURE_ORGANIZATIONS)).toThrow(
+      new RegExp(`Cannot find module '${FIXTURE_ORGANIZATIONS}'`),
+    );
+  });
+
+  it('and the REAL package is reachable from that same anchor — the asymmetry is the point', () => {
+    // The other half of leg 2, and the one that makes this file's history
+    // legible: from the very same host root, the real subject DOES resolve,
+    // through the hoisted store the launcher's NODE_PATH exposes. That is not a
+    // defect to fix here (ADR-0132 put the package in this workspace on
+    // purpose); it is the reason the CONTROL may not be built on that name.
+    //
+    // ⚠️ Build-state dependent BY CONSTRUCTION, so it asserts reachability of
+    // the package DIRECTORY rather than a loadable entry: `require.resolve`
+    // throws MODULE_NOT_FOUND for an unbuilt package too, and pinning "it
+    // resolves" would make this case itself a verdict about whether a sibling
+    // package had been built — the defect it documents.
+    let resolved: string | undefined;
+    let resolveError: string | undefined;
+    try {
+      resolved = createHostRequire(appDeclaredNotInstalled).resolve(ORGANIZATIONS_PKG);
+    } catch (e) {
+      resolveError = (e as Error).message;
+    }
+    // Two legal shapes, and each asserts its own discriminating fact — ⛔ not
+    // one assertion that a `undefined` would satisfy vacuously.
+    if (resolved !== undefined) {
+      // Built tree: it resolved, and NOT out of this host root — which is the
+      // whole mechanism, stated as an assertion.
+      expect(resolved).not.toContain(appDeclaredNotInstalled);
+    } else {
+      // Unbuilt tree: the package DIRECTORY is still reachable, so the throw
+      // names a path inside the store. What must never happen is the
+      // bare-specifier failure leg 2 asserts for the fixture — that is the one
+      // reading that would make the two subjects interchangeable.
+      expect(resolveError).not.toMatch(new RegExp(`Cannot find module '${ORGANIZATIONS_PKG}'`));
+    }
+  });
+
+  it('and bootStack still binds the ENTERPRISE package as its default subject', () => {
+    // What the fixture subject must NOT quietly become: the default. Production
+    // callers pass no `organizationsPackage`, and the one they get is the real
+    // package — behaviourally pinned by the four cases above, which pass no
+    // option and are decided by the real name.
+    expect(ORGANIZATIONS_PKG).toBe('@objectstack/organizations');
+    expect(FIXTURE_ORGANIZATIONS).not.toBe(ORGANIZATIONS_PKG);
+    expect(FIXTURE_ORGANIZATIONS.startsWith('@fixture/')).toBe(true);
+  });
+});
@@ -85,6 +85,18 @@ const DEFAULT_ADMIN_EMAIL = 'admin@objectos.ai';
 const DEFAULT_ADMIN_PASSWORD = 'admin123';
 const DEFAULT_AUTH_SECRET = 'objectstack-verify-secret';
 
+/**
+ * The enterprise multi-org runtime this harness mounts under `multiTenant: true`
+ * — the one and only subject `bootStack` resolves from the host app, and the
+ * default of {@link BootOptions.organizationsPackage}.
+ *
+ * Exported for the host-resolution suite's premise case, which pins this value
+ * so a test seam can never quietly become the production subject. ⛔ Deliberately
+ * NOT re-exported from `./index.ts`: it is not part of this package's published
+ * API.
+ */
+export const ORGANIZATIONS_PKG = '@objectstack/organizations';
+
 /**
  * A booted stack: the HTTP surface (`api` / `raw` / `signIn` / `signUp` /
  * `apiAs`) plus the in-process handle (`hooks` / `validate` / `flows` /
@@ -347,6 +359,36 @@ export interface BootOptions {
    * array order. Default `[]`.
    */
   extraPlugins?: unknown[];
+  /**
+   * The specifier `multiTenant: true` resolves from the host app. Defaults to
+   * the real subject, {@link ORGANIZATIONS_PKG}; ⛔ production callers never
+   * pass it.
+   *
+   * ## Why it exists (#17911, the same repair #16539 / #16552 landed)
+   *
+   * Every verdict this boot path reaches is a statement about what a host root
+   * HAS and, just as load-bearing, what it has NOT got. Until ADR-0132 / #16215
+   * the second half came free: `@objectstack/organizations` was cloud-private,
+   * so a temp host that declared it and did not install it was unresolvable by
+   * construction. It is a tracked workspace package now; pnpm's hoisted store
+   * carries it and every `pnpm exec`-launched runner (vitest's bin shim
+   * included) exports a `NODE_PATH` that reaches that store. From then on a
+   * "declared, not installed" fixture's verdict was a function of whether an
+   * unrelated package had been BUILT — green on CI, whose test graph never
+   * builds it, red on any tree that had run a full local build.
+   *
+   * The visible half of that is a false red. The half that matters is the quiet
+   * one: a fixture whose subject is reachable is no longer deciding what the
+   * host root has, and nothing says so. So a case that needs the absence to be
+   * a property of ITS OWN directory hands in a name this workspace can never
+   * contain (`@fixture/*`) and proves the absence rather than assuming it — and
+   * no workspace name is safe from becoming one.
+   *
+   * ⛔ It does NOT rename the package in the operator-facing sentence: the error
+   * this boot throws names {@link ORGANIZATIONS_PKG} literally, because in every
+   * production boot that is the subject. Only the specifier moves.
+   */
+  organizationsPackage?: string;
 }
 
 /**
@@ -548,7 +590,11 @@ export async function bootStack(
     // package declares it — and it is what stops the next app-supplied
     // package added to this path from silently missing `packages/verify`'s own
     // dependencies.
-    const organizationsPkg = '@objectstack/organizations';
+    // #17911: the subject is a parameter with the real package as its default,
+    // so a fixture case whose whole content is "this host root does NOT have
+    // it" can hand in a name the workspace can never supply. Production callers
+    // pass nothing and get `ORGANIZATIONS_PKG` — see BootOptions.organizationsPackage.
+    const organizationsPkg = opts.organizationsPackage ?? ORGANIZATIONS_PKG;
     const hostRoot = opts.hostRoot ?? process.cwd();
     let mod: any;
     try {