@@ -0,0 +1,13 @@
+---
+'@objectstack/verify': patch
+---
+
+fix(verify): `bootStack` composes the artifact-less `MetadataPlugin` that `objectstack serve` gives a host configuration, so a stack's declared `apis` endpoints answer under the harness as they answer under `serve` (#23088)
+
+Clause-②: no
+
+`bootStack`'s `metadata` slot was the kernel's in-memory fallback, which has no endpoint matcher (`matchEndpoint`). So every `apis` endpoint a stack declared answered `404 ENDPOINT_NOT_FOUND` in a test boot while `objectstack serve` of the same stack served it, and the boot logged `AppPlugin`'s "no endpoint matcher" warning. The harness now composes `@objectstack/metadata`'s `MetadataPlugin` the way `serve` composes it for a host configuration: no artifact, `bootstrap: 'lazy'`, and `rootDir` set to `BootOptions.hostRoot`. It reads none of the stack, so `AppPlugin` stays the single registrar of the stack's metadata.
+
+- A declared endpoint answers as it does under `serve`: `401` without a session where it is `authRequired`, and its declared answer with one. An undeclared path under the same mount keeps the bare `404`.
+- A `MetadataPlugin` you pass in `BootOptions.extraPlugins`, or one your app declares in its own `plugins`, takes the composed one's place. Pass your own to boot an artifact-backed one.
+- Two other answers of a test boot move with the slot: `GET /api/v1/discovery` reports the `metadata` service as `available` instead of `degraded`, and `GET /api/v1/dev/metadata-events` (the development-only metadata reload stream, mounted because `bootStack` boots in the development posture) answers `200` instead of `404`, as under `objectstack dev`. The `GET /api/v1/meta/TYPE` answers are unchanged, measured over 22 types on the showcase and CRM examples.
@@ -21,10 +21,10 @@
 // an object saved through `PUT /meta/object/:name` is listed with a real
 // verdict (it declares a column the remote lacks, and exactly that column is
 // reported); an object imported through `…/external/tables/:remote/import` is
-// listed beside them. The verify harness composes no metadata plugin, so its
-// `metadata` service is the kernel's fallback registered after the
-// federation service's `init()`, as on `objectstack start`; the service reads
-// it when validation runs ([#21876]), so each row here is a real comparison.
+// listed beside them. The verify harness composes `@objectstack/metadata`'s
+// artifact-less `MetadataPlugin`, as `objectstack serve` does for a host
+// configuration (#23088); the service resolves what it reads when validation
+// runs ([#21876]), so each row here is a real comparison.
 // The seam pins sit beside the plugin
 // (`packages/services/service-datasource/src/__tests__/external-validate-reads-live-registry.test.ts`).
 //
 
@@ -1,29 +1,31 @@
 // Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
 //
-// [#21876] On a composition with no metadata plugin — the `objectstack start`
-// shape — the federation service compares every federated object.
+// [#21876] The federation service compares every federated object, on the
+// composition the verify harness boots.
 //
 // ## What was broken
 //
 // `ExternalDatasourceServicePlugin.init()` read the `metadata` service once and
-// kept the answer. `objectstack start` composes no metadata plugin: its
-// `metadata` service is the kernel's in-memory fallback, registered after every
-// plugin's `init()`, just before the start phase. So the federation service
-// kept "no metadata service" for the life of the process. Measured on the
-// showcase under `objectstack start`: `POST /datasources/:name/external/validate`
-// answered `ok: true` with no rows, and the boot gate logged "all federated
-// objects match their remote schema" with `objects: 0` — although two
-// federated objects exist, and one of them could have drifted. Under
-// `objectstack dev` (which composes the metadata plugin before this one) both
-// objects were compared. The service now resolves `metadata` when it is used.
+// kept the answer. On a composition with no metadata plugin, that service is
+// the kernel's in-memory fallback, registered after every plugin's `init()`,
+// just before the start phase. So the federation service kept "no metadata
+// service" for the life of the process. Measured on the showcase at the time:
+// `POST /datasources/:name/external/validate` answered `ok: true` with no rows,
+// and the boot gate logged "all federated objects match their remote schema"
+// with `objects: 0` — although two federated objects exist, and one of them
+// could have drifted. The service now resolves `metadata` when it is used.
+// That ordering fix is pinned at its seam, in
+// `packages/services/service-datasource/src/__tests__/external-validate-reads-live-registry.test.ts`.
 //
 // ## Why this composition
 //
-// The verify harness composes no metadata plugin either, so its `metadata`
-// service is the same kernel fallback, registered at the same moment, as on
-// `objectstack start`. The first case asserts that, so a harness that one day
-// composes a metadata plugin cannot turn this file into a silent pass. The
-// harness does not mount the federation service, so this file mounts it, as
+// The verify harness composes `@objectstack/metadata`'s `MetadataPlugin`, the
+// artifact-less one `objectstack serve` and `start` give a host configuration
+// such as the showcase (#23088). The first case asserts that occupant: the
+// plugin is registered, and the `metadata` service is its manager, with the
+// endpoint matcher. So a change to what the harness composes cannot pass
+// through this file unnoticed. The harness does not mount the federation
+// service, so this file mounts it, as
 // `objectstack dev` and `start` do. It does not mount the boot gate either
 // (`createExternalValidationPlugin`, `@objectstack/runtime`): the gate's input
 // is the federation service's whole-farm sweep, `validateAll()`, which the
@@ -41,6 +43,7 @@
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
 import showcaseStack, { onEnable } from '@objectstack/example-showcase';
 import { ExternalDatasourceServicePlugin, resolveSqliteDriver } from '@objectstack/service-datasource';
+import { MetadataManager } from '@objectstack/metadata';
 import { type VerifyStack } from '@objectstack/verify';
 import { bootShowcase } from './showcase-boot.js';
 import { mkdtempSync, rmSync } from 'node:fs';
@@ -82,7 +85,7 @@ async function driftRemoteCustomers(): Promise<void> {
   }
 }
 
-describe('federation on a composition with no metadata plugin (the objectstack start shape)', () => {
+describe('federation on the harness composition, which holds the metadata plugin', () => {
   let stack: VerifyStack;
   let token: string;
   let prevCwd: string;
@@ -107,10 +110,14 @@ describe('federation on a composition with no metadata plugin (the objectstack s
     if (dir) rmSync(dir, { recursive: true, force: true });
   });
 
-  it('precondition: the metadata service is the kernel\'s in-memory fallback, as on objectstack start', () => {
-    const metadata = stack.kernel.getService<{ __serviceInfo?: { status?: string; message?: string } }>('metadata');
-    expect(metadata.__serviceInfo?.status).toBe('degraded');
-    expect(metadata.__serviceInfo?.message).toMatch(/^In-memory metadata registry/);
+  it('precondition: the metadata service is the composed MetadataPlugin\'s manager, with its endpoint matcher', () => {
+    // The plugin is registered under its own name, and the `metadata` slot is
+    // its `MetadataManager`, not the kernel's in-memory fallback (a plain
+    // object with no matcher).
+    expect(stack.kernel.hasPlugin('com.objectstack.metadata')).toBe(true);
+    const metadata = stack.kernel.getService<{ matchEndpoint?: unknown }>('metadata');
+    expect(metadata).toBeInstanceOf(MetadataManager);
+    expect(typeof metadata.matchEndpoint).toBe('function');
   });
 
   it('validate compares each federated object, and reports the drifted column', async () => {
 
@@ -160,8 +160,9 @@ describe('dogfood: one artifact, two co-owning packages (ADR-0130 D4)', () => {
 // #14599 — the METADATA door, which the block above does not reach
 // ───────────────────────────────────────────────────────────────────────────
 //
-// `bootStack` registers `AppPlugin` and no `MetadataPlugin`, so everything
-// above is measured on the ObjectQL registry alone. The defect this block pins
+// `bootStack` registers `AppPlugin` and a `MetadataPlugin` with no artifact,
+// which loads none of the stack (#23088), so everything above is measured on
+// the ObjectQL registry alone. The defect this block pins
 // lives in the OTHER reader — `MetadataPlugin._parseAndRegisterArtifact`, the
 // door a real `objectstack dev` / `objectstack serve` boot loads the artifact
 // through — and the two only disagree once both are present. That is why this
 
@@ -13,10 +13,10 @@
 // unit-tested by calling `dispatch()` directly, which is why nobody noticed
 // that no route ever mounted the paths it claimed to serve.
 //
-// So this file stubs NOTHING. It boots the real showcase app, through the real
-// artifact ingestion path (`MetadataPlugin` + a `local-file` artifact — the
-// same path `objectstack dev` / `serve` take), over the real Hono transport,
-// and asks the questions a caller asks:
+// So this file stubs NOTHING. It boots the real showcase app as
+// `objectstack serve` boots this host configuration — the harness's own
+// artifact-less `MetadataPlugin`, with `AppPlugin` registering the declared
+// endpoints — over the real Hono transport, and asks the questions a caller asks:
 //
 //   1. does a declared endpoint answer at all, and with the SAME body the
 //      built-in route gives for the same operation (#5040 §4's red line);
@@ -53,7 +53,6 @@ import { fileURLToPath } from 'node:url';
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
 import { type VerifyStack } from '@objectstack/verify';
 import { bootShowcase } from './showcase-boot.js';
-import { MetadataPlugin } from '@objectstack/metadata';
 import { ConnectorRestPlugin } from '@objectstack/connector-rest';
 import { ConnectorOpenApiPlugin } from '@objectstack/connector-openapi';
 import { ConnectorMcpPlugin } from '@objectstack/connector-mcp';
@@ -82,26 +81,30 @@ let tempDir: string;
 let prevCwd: string;
 let stack: VerifyStack;
 let adminToken: string;
-/** Read back off disk — what `MetadataPlugin` actually ingested, not what we meant to write. */
+/** Read back off disk — what the build-shaped writer actually wrote, not what we meant to write. */
 let artifactOnDisk: Record<string, unknown>;
 
 /**
  * Boot the showcase the way a deployment boots it.
  *
- * `@objectstack/verify`'s lean harness composes no `MetadataPlugin` — its
- * proofs are data/authorization ones that read metadata straight off the
- * config. A declared endpoint cannot be reached without one: `matchEndpoint`
- * is `IMetadataService`'s member, and `NodeMetadataManager` is its only
- * implementation. So this file supplies it through the harness's `extraPlugins`
- * seam, pointed at an artifact written from the showcase's own stack
- * definition — the SAME `artifactSource: { mode: 'local-file' }` ingestion
- * `createStandaloneStack` uses, which is what maps `apis:` → `api` metadata
- * items (`ARTIFACT_FIELD_TO_TYPE` in `packages/metadata/src/plugin.ts`).
+ * A declared endpoint cannot be reached without a `MetadataPlugin`:
+ * `matchEndpoint` is `IMetadataService`'s member, and `NodeMetadataManager` is
+ * its only implementation. `@objectstack/verify`'s `bootStack` composes the one
+ * `objectstack serve` composes for a host configuration such as this one — no
+ * artifact, so `AppPlugin` registers the showcase's `apis:` as `api` items
+ * (#23088). This file used to hand in an artifact-backed `MetadataPlugin`
+ * through `extraPlugins`, because the harness composed none; it no longer does,
+ * so the endpoints below are the ones a deployment of this configuration
+ * serves, booted with nothing the harness does not compose itself. The
+ * artifact door's `apis:` → `api` ingestion (`ARTIFACT_FIELD_TO_TYPE` in
+ * `packages/metadata/src/plugin.ts`) keeps its own proofs
+ * (`declarative-endpoint-policy.dogfood.test.ts`,
+ * `declarative-endpoint-anonymous-guest.dogfood.test.ts`).
  *
- * Writing the artifact through `ObjectStackDefinitionSchema` — which the
- * ingest performs on load — means this boot ALSO re-proves the E7 publish
- * gates accept the restored declarations. A declaration that could not publish
- * could not be ingested here either.
+ * The artifact is still written, through the build's own
+ * `ObjectStackDefinitionSchema` parse, so this file still re-proves the E7
+ * publish gates accept the restored declarations, and the cases in section 0
+ * read it back.
  */
 beforeAll(async () => {
   prevCwd = process.cwd();
@@ -137,13 +140,6 @@ beforeAll(async () => {
       new ConnectorRestPlugin(),
       new ConnectorOpenApiPlugin(),
       new ConnectorMcpPlugin({ declarativeStdio: ['node'] }),
-      new MetadataPlugin({
-        rootDir: tempDir,
-        watch: false,
-        artifactWatch: false,
-        registerSystemObjects: false,
-        artifactSource: { mode: 'local-file', path: artifactPath },
-      }),
     ],
   });
   adminToken = await stack.signIn();
@@ -156,7 +152,7 @@ afterAll(async () => {
 });
 
 // ============================================================================
-// 0. The artifact this boot ingests is the shape the build writes (commit c39a911ae)
+// 0. The showcase's stand-in artifact is the shape the build writes (commit c39a911ae)
 // ============================================================================
 
 describe('[#6293] the stand-in artifact carries what a built one carries', () => {
 
@@ -28,6 +28,7 @@
   "dependencies": {
     "@objectstack/core": "workspace:*",
     "@objectstack/mcp": "workspace:*",
+    "@objectstack/metadata": "workspace:*",
     "@objectstack/objectql": "workspace:*",
     "@objectstack/platform-objects": "workspace:*",
     "@objectstack/plugin-approvals": "workspace:*",
 
@@ -0,0 +1,142 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * #23088: `bootStack` fills its `metadata` slot the way `objectstack serve`
+ * fills it for a host configuration (#22989): `@objectstack/metadata`'s
+ * `MetadataPlugin` with no artifact. Before, the slot was the kernel's
+ * in-memory fallback, which has no `matchEndpoint`, so every `apis` endpoint a
+ * stack declared answered `404 ENDPOINT_NOT_FOUND` under the harness while
+ * `serve` served it, and the boot logged `AppPlugin`'s no-matcher warning.
+ *
+ * Two boots:
+ *
+ *  - the harness's own composition (nothing in `extraPlugins`): the declared
+ *    path answers 401 without a session and 200 with one, an undeclared path
+ *    under the same mount keeps the bare 404, and the no-matcher warning is
+ *    not logged;
+ *  - a caller's own `MetadataPlugin` in `extraPlugins`: that instance holds
+ *    the slot, and the composed one is never registered (no supersede).
+ *
+ * Warnings are identified by their named subjects and structured fields (the
+ * app id, the remedy plugin, the superseded plugin's name), never by prose.
+ */
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { MetadataPlugin } from '@objectstack/metadata';
+import { defineStack } from '@objectstack/spec';
+import { bootStack, type VerifyStack } from './harness.js';
+
+const BOOT_TIMEOUT = 120_000;
+const APP_ID = 'com.example.mdoor';
+const FEED = '/apps/mdoor/notes';
+
+/** A fresh configuration per boot: the instance rule keys on identity. */
+const stackWithApi = () =>
+  defineStack({
+    manifest: { id: APP_ID, name: 'Metadata Door', version: '1.0.0', type: 'app', namespace: 'mdoor' },
+    objects: [
+      {
+        name: 'mdoor_note',
+        label: 'Note',
+        pluralLabel: 'Notes',
+        sharingModel: 'public_read_write',
+        fields: { title: { name: 'title', type: 'text', label: 'Title' } },
+      },
+    ],
+    apis: [
+      {
+        name: 'mdoor_note_feed',
+        path: `/api/v1${FEED}`,
+        method: 'GET',
+        summary: 'Note feed',
+        type: 'object_operation',
+        objectParams: { object: 'mdoor_note', operation: 'find' },
+        authRequired: true,
+      },
+    ],
+  } as never) as unknown as Record<string, unknown>;
+
+/** Every structured kernel-log line the boot wrote to stdout, ANSI stripped. */
+async function bootCapturing(config: unknown, extraPlugins?: unknown[]): Promise<{ stack: VerifyStack; lines: string[] }> {
+  const lines: string[] = [];
+  const spy = vi.spyOn(process.stdout, 'write').mockImplementation(((chunk: unknown) => {
+    lines.push(...String(chunk).replace(/\u001b\[[0-9;]*m/g, '').split('\n'));
+    return true;
+  }) as never);
+  try {
+    const stack = await bootStack(config, extraPlugins ? { extraPlugins } : {});
+    return { stack, lines };
+  } finally {
+    spy.mockRestore();
+  }
+}
+
+/** The structured fields a kernel `WARN` line carries, or undefined for any other line. */
+function warnFields(line: string): Record<string, unknown> | undefined {
+  if (!/ WARN /.test(line)) return undefined;
+  const at = line.indexOf(' {');
+  if (at < 0) return undefined;
+  try {
+    return JSON.parse(line.slice(at + 1)) as Record<string, unknown>;
+  } catch {
+    return undefined;
+  }
+}
+
+let stack: VerifyStack | undefined;
+afterEach(async () => {
+  await stack?.stop();
+  stack = undefined;
+});
+
+describe('#23088 bootStack serves a declared endpoint, as objectstack serve does', () => {
+  it('composes a matcher, so the declared path is gated and served, and no matcher warning is logged', async () => {
+    const booted = await bootCapturing(stackWithApi());
+    stack = booted.stack;
+    const token = await stack.signIn();
+
+    const answer = async (res: Response) => ({
+      status: res.status,
+      code: ((await res.json()) as { error?: { code?: string } }).error?.code,
+    });
+    const observed = {
+      // The slot carries the endpoint matcher.
+      matcher: typeof stack.kernel.getService<{ matchEndpoint?: unknown }>('metadata').matchEndpoint,
+      anonymous: await answer(await stack.api(FEED, { method: 'GET' })),
+      signedIn: (await stack.apiAs(token, 'GET', FEED)).status,
+      // CONTROL: an undeclared path under the same mount keeps the bare 404.
+      undeclared: await answer(await stack.apiAs(token, 'GET', '/apps/mdoor/no-such-endpoint')),
+      matcherWarnings: booted.lines.filter((line) => {
+        const fields = warnFields(line);
+        return fields?.appId === APP_ID && line.includes('MetadataPlugin');
+      }),
+    };
+    // One composite, so a failure shows every observation at once.
+    expect(observed).toEqual({
+      matcher: 'function',
+      anonymous: { status: 401, code: 'UNAUTHENTICATED' },
+      signedIn: 200,
+      undeclared: { status: 404, code: 'ENDPOINT_NOT_FOUND' },
+      matcherWarnings: [],
+    });
+  }, BOOT_TIMEOUT);
+
+  it("a caller's own MetadataPlugin in extraPlugins holds the slot, and the composed one is never registered", async () => {
+    const own = new MetadataPlugin({ watch: false, config: { bootstrap: 'lazy' } });
+    const booted = await bootCapturing(stackWithApi(), [own]);
+    stack = booted.stack;
+
+    // The slot is the caller's instance's manager — by identity.
+    const ownManager = (own as unknown as { manager: unknown }).manager;
+    expect(stack.kernel.getService('metadata')).toBe(ownManager);
+
+    // Composed and then superseded would log the kernel's supersede warning
+    // for this name; not composed logs none.
+    const superseded = booted.lines.filter((line) => warnFields(line)?.plugin === own.name);
+    expect(superseded).toEqual([]);
+
+    // And the caller's instance serves the declared path.
+    const anonymous = await stack.api(FEED, { method: 'GET' });
+    expect(anonymous.status).toBe(401);
+  }, BOOT_TIMEOUT);
+});