@@ -0,0 +1,16 @@
+---
+'@objectstack/verify': minor
+---
+
+feat(verify): `bootStack(config, { artifact })` boots the compiled artifact as the app, so a test runs each hook's and action's lowered `body` in the sandbox, as a deployment does
+
+Clause-②: yes (widening)
+
+`objectstack build` lowers each inline hook `handler` and action `target` it can into a metadata-only `body`, and a deployment runs that body in the runtime's QuickJS sandbox, against the sandbox's `ctx`. `bootStack` mounted the source configuration only, so a handle test ran the function in-process, and a handler that refuses once lowered passed every test.
+
+- **`BootOptions.artifact`** names the compiled `objectstack.json`: a path, resolved against `hostRoot` (so `'dist/objectstack.json'` names the app's own build), or an `http(s)://` URL. The artifact is read by the runtime's own artifact loader (`loadArtifactBundle`, with the options every artifact boot reads it with) and mounted as the app, in place of `config`. `AppPlugin` binds each hook's `body` ahead of its `handler`, through the same sandbox runner every artifact boot uses, so every door (`hooks.run`, `actions.run`, `api`, …) runs what the build shipped.
+- **A refused body answers as the body-only path answers.** The handle rejects with the sandbox's `SandboxError`, which carries a `code` and `status` the body declared on its throw. A body that crashes (a `TypeError`) carries none, and REST answers it `500` `INTERNAL_ERROR`. For example, a handler that writes to `ctx.dispatch.scope` passes in-process and refuses every insert once lowered, because the sandbox hands a body `ctx.dispatch` without `scope`.
+- **The rest of the stack is still composed from `config`**: its `requires`, its own `plugins`, its declared default profile, its datasources. `objectstack serve <config>` composes the same way. So `config` is the configuration the artifact was built from.
+- **A local artifact gets its `objectstack-runtime.*.mjs` merged**, so a callable the build could not lower runs in-process from it, as under `objectstack start`. `objectstack build --strict-body` refuses such a callable at build time, and its artifact is body-only.
+- **Refused before anything boots**, each with its `code` and `status`: an artifact that cannot be loaded (`RESOURCE_NOT_FOUND`, 404; the boot never falls back to the source), an artifact built from another app (`RESOURCE_CONFLICT`, 409), and a configuration carrying `onEnable` (`INVALID_REQUEST`, 400). No artifact carries `onEnable`; for a configuration that mounts no plugin instance of its own, `objectstack serve <config>` grafts it from the configuration module, a `@objectstack/cli` rule this package does not re-derive. No error code is added.
+- The handle lowers nothing: build the artifact first. A stale artifact boots stale bodies.
@@ -0,0 +1,194 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * #22301 item 7 — a hook handler that passes an in-process test and refuses
+ * the write once the build lowers it, and the door that lets an app's test see
+ * it: `bootStack(config, { artifact })` (`@objectstack/verify`), which mounts
+ * the compiled artifact as the app.
+ *
+ * The artifact is written by `buildShapedArtifact`, which runs the build's own
+ * pipeline (`normalizeStackInput` → `lowerCallables` →
+ * `ObjectStackDefinitionSchema`, reaching the lowering in `@objectstack/cli`'s
+ * source). So each hook reaches the artifact boot as the `body` the real
+ * lowering extracted from its handler, never a body written here. Every
+ * handler lowers (asserted below), so the real build emits no runtime module
+ * for this app either: the artifact is body-only.
+ *
+ * Each hook is driven on both boots, the source configuration (the handler,
+ * in-process) and its artifact (the body, in the runtime's QuickJS sandbox):
+ *
+ *  - `lbd_stash` writes to `ctx.dispatch.scope`, the cross-phase scratch the
+ *    hook contract names (`HookContextSchema.dispatch`). The sandbox hands a
+ *    body `ctx.dispatch` as `{ mode, index }`, without `scope`, so the body
+ *    throws a TypeError and the write is refused. The handler passes. This is
+ *    the divergence.
+ *  - `lbd_refuse` refuses a short name with a declared `VALIDATION_FAILED` /
+ *    400. Both boots refuse. In-process the caller gets the handler's own
+ *    error; on the body-only path it gets a `SandboxError` that carries the
+ *    declared `code` and `status` out of the VM. This is the refusal envelope.
+ *  - `lbd_derive` derives a field. Both boots store the same value. This is
+ *    the control.
+ *
+ * Measured before the door (`origin/main` a8f24b092c): `bootStack` always
+ * mounted the source configuration, so the first hook passed every handle
+ * test while the artifact it ships refuses every insert.
+ */
+
+import { mkdtempSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import { bootStack, type VerifyStack } from '@objectstack/verify';
+import { defineStack } from '@objectstack/spec';
+import { writeBuildShapedArtifact, type BuildShapedArtifact } from './build-shaped-artifact.js';
+
+type HookCtx = { input: Record<string, unknown>; dispatch: { scope: Record<string, unknown> } };
+
+const text = (name: string, label: string) => ({ name, type: 'text', label });
+const object = (name: string) => ({
+  name,
+  label: name,
+  pluralLabel: name,
+  sharingModel: 'public_read_write',
+  fields: { name: { ...text('name', 'Name'), required: true }, note: text('note', 'Note') },
+});
+
+/** The configuration, BUILT AGAIN on each call: each boot, and the build, gets its own. */
+const buildApp = (): Record<string, unknown> =>
+  defineStack({
+    manifest: { id: 'com.example.lowered-body-door', name: 'Lowered Body Door', namespace: 'lbd', version: '1.0.0', type: 'app' },
+    objects: [object('lbd_stash_note'), object('lbd_refuse_note'), object('lbd_derive_note')],
+    hooks: [
+      {
+        name: 'lbd_stash',
+        object: 'lbd_stash_note',
+        events: ['beforeInsert'],
+        handler: async (ctx: HookCtx) => {
+          ctx.dispatch.scope.stashed = ctx.input.name;
+          ctx.input.note = 'stashed';
+        },
+      },
+      {
+        name: 'lbd_refuse',
+        object: 'lbd_refuse_note',
+        events: ['beforeInsert'],
+        handler: async (ctx: HookCtx) => {
+          if (String(ctx.input.name ?? '').length < 3) {
+            throw Object.assign(new Error('the name is too short'), { code: 'VALIDATION_FAILED', status: 400 });
+          }
+        },
+      },
+      {
+        name: 'lbd_derive',
+        object: 'lbd_derive_note',
+        events: ['beforeInsert'],
+        handler: async (ctx: HookCtx) => {
+          ctx.input.note = 'derived:' + String(ctx.input.name);
+        },
+      },
+    ],
+  } as never) as unknown as Record<string, unknown>;
+
+let tempDir: string;
+let built: BuildShapedArtifact;
+let source: VerifyStack;
+let lowered: VerifyStack;
+let sourceToken: string;
+let loweredToken: string;
+
+beforeAll(async () => {
+  tempDir = mkdtempSync(join(tmpdir(), 'dogfood-lowered-body-door-'));
+  const artifactPath = join(tempDir, 'objectstack.json');
+  built = writeBuildShapedArtifact(buildApp(), artifactPath);
+  source = await bootStack(buildApp());
+  lowered = await bootStack(buildApp(), { artifact: artifactPath });
+  sourceToken = await source.signIn();
+  loweredToken = await lowered.signIn();
+}, 240_000);
+
+afterAll(async () => {
+  await source?.stop();
+  await lowered?.stop();
+  if (tempDir) rmSync(tempDir, { recursive: true, force: true });
+});
+
+/** What a call rejected with, or a failure naming what it resolved with. */
+const rejection = async (call: Promise<unknown>): Promise<Record<string, unknown>> => {
+  try {
+    const value = await call;
+    throw new Error(`expected a refusal, got ${JSON.stringify(value)}`);
+  } catch (e) {
+    return e as Record<string, unknown>;
+  }
+};
+
+const insert = (stack: VerifyStack, object: string, name: string) =>
+  stack.hooks.run(object, 'insert', { name }, { system: true });
+
+describe('the artifact under test is what the build lowers', () => {
+  it('every hook reaches the artifact as a body the real lowering extracted from its handler', () => {
+    const hooks = (built.artifact.hooks ?? []) as Array<Record<string, unknown>>;
+    expect(hooks.map((h) => h.name).sort()).toEqual(['lbd_derive', 'lbd_refuse', 'lbd_stash']);
+    for (const hook of hooks) {
+      expect((hook.body as { source?: unknown } | undefined)?.source, `${String(hook.name)} lowered`).toEqual(
+        expect.any(String),
+      );
+    }
+    expect(built.refs).toEqual(['lbd_derive', 'lbd_refuse', 'lbd_stash']);
+  });
+});
+
+describe('the divergence: a handler that passes in-process and refuses once lowered', () => {
+  it('in-process, the handler stashes on `ctx.dispatch.scope` and the insert is stored', async () => {
+    const row = await insert(source, 'lbd_stash_note', 'alpha');
+    expect(row.note).toBe('stashed');
+  });
+
+  it('lowered, the body meets a `ctx.dispatch` without `scope`: a TypeError, and the insert is refused', async () => {
+    const e = await rejection(insert(lowered, 'lbd_stash_note', 'alpha'));
+    expect(e.name).toBe('SandboxError');
+    expect(String(e.message)).toMatch(/^hook 'lbd_stash' threw: TypeError/);
+    expect(e.code).toBeUndefined();
+    expect(await lowered.rows('lbd_stash_note')).toEqual([]);
+  });
+
+  it('over REST: created in-process, a 500 once lowered', async () => {
+    const ok = await source.apiAs(sourceToken, 'POST', '/data/lbd_stash_note', { name: 'beta' });
+    expect(ok.status).toBeLessThan(300);
+    const refused = await lowered.apiAs(loweredToken, 'POST', '/data/lbd_stash_note', { name: 'beta' });
+    expect(refused.status).toBe(500);
+    expect(await refused.json()).toMatchObject({ code: 'INTERNAL_ERROR' });
+  });
+});
+
+describe('the refusal envelope: a declared refusal, as each path answers it', () => {
+  it("in-process, the caller gets the handler's own error", async () => {
+    const e = await rejection(insert(source, 'lbd_refuse_note', 'ab'));
+    expect(e).toMatchObject({ name: 'Error', code: 'VALIDATION_FAILED', status: 400 });
+  });
+
+  it('lowered, a SandboxError carries the declared code and status out of the VM', async () => {
+    const e = await rejection(insert(lowered, 'lbd_refuse_note', 'ab'));
+    expect(e).toMatchObject({ name: 'SandboxError', code: 'VALIDATION_FAILED', status: 400 });
+    expect(await lowered.rows('lbd_refuse_note')).toEqual([]);
+  });
+
+  it('over REST, both paths answer the declared envelope, the same body on the wire', async () => {
+    const bodies: unknown[] = [];
+    for (const [stack, token] of [[source, sourceToken], [lowered, loweredToken]] as const) {
+      const res = await stack.apiAs(token, 'POST', '/data/lbd_refuse_note', { name: 'ab' });
+      expect(res.status).toBe(400);
+      const body = await res.json();
+      expect(body).toMatchObject({ code: 'VALIDATION_FAILED' });
+      bodies.push(body);
+    }
+    expect(bodies[1]).toEqual(bodies[0]);
+  });
+});
+
+describe('control: a lowerable hook behaves identically both ways', () => {
+  it('both boots store the derived value', async () => {
+    expect((await insert(source, 'lbd_derive_note', 'gamma')).note).toBe('derived:gamma');
+    expect((await insert(lowered, 'lbd_derive_note', 'gamma')).note).toBe('derived:gamma');
+  });
+});
@@ -195,6 +195,44 @@ await stack.stop();
   one module, under vitest `isolate: false`, and never `stop()` a stack other
   files still use.
 
+### What the build ships: boot the compiled artifact
+
+`objectstack build` lowers each inline hook `handler` and action `target` it
+can into a metadata-only `body`, and a deployment runs that body in the
+runtime's QuickJS sandbox, against the sandbox's `ctx`. A source boot runs the
+function in-process instead. To test what ships, boot the artifact:
+
+```ts
+// After `objectstack build` (the handle lowers nothing; build first).
+const shipped = await bootStack(myApp, { artifact: 'dist/objectstack.json' });
+
+// Every door now runs the lowered body. A handler that passes in-process can
+// refuse here: a body meets the sandbox's `ctx`, which has no
+// `ctx.dispatch.scope`, for one.
+await expect(shipped.hooks.run('crm_lead', 'insert', { last_name: 'Ada' }, { system: true }))
+  .rejects.toMatchObject({ name: 'SandboxError' });
+```
+
+- The artifact is read by the runtime's own artifact loader and mounted as the
+  app, in place of `config`; the rest of the stack is still composed from
+  `config` (its `requires`, its `plugins`, its default profile), as
+  `objectstack serve <config>` composes it. A relative path resolves against
+  `hostRoot`.
+- A refused body answers as the body-only path answers: the handle rejects with
+  the sandbox's `SandboxError`, which carries a `code` and `status` the body
+  declared on its throw; a body that crashes (a `TypeError`) has none, and REST
+  answers it `500` `INTERNAL_ERROR`.
+- A callable the build could not lower is bundled into
+  `objectstack-runtime.*.mjs`, which a local artifact boot merges, so it runs
+  in-process here as under `objectstack start`. `objectstack build
+  --strict-body` refuses it at build time instead, and its artifact is
+  body-only.
+- Refused before anything boots: an artifact that cannot be loaded
+  (`RESOURCE_NOT_FOUND` / 404; the boot never falls back to the source), one
+  built from another app (`RESOURCE_CONFLICT` / 409), and a configuration
+  carrying `onEnable`, which no artifact carries (`INVALID_REQUEST` / 400). A
+  stale artifact boots stale bodies: build before the run.
+
 ## Verdicts
 
 **Data fidelity** (`runCrudVerification`):
@@ -258,7 +296,8 @@ for owner-scoped fixtures), `multiTenant` (also what decides the posture
 `tenancy()` reports), `automation` (register the automation service so
 `flows.*` and `automation.evaluateCondition` have something to drive; an app
 that declares `requires: ['automation']` gets it without this), `orgContext`,
-`databaseFile`, `extraPlugins`.
+`databaseFile`, `extraPlugins`, `artifact` (boot the compiled artifact as the
+app, so hooks and actions run their lowered `body`).
 
 ## Known limitations
 
 
@@ -70,6 +70,16 @@
 //   metadata                             → the engine's `SchemaRegistry`.
 //   tenancy                              → the `tenancy` service AuthPlugin
 //     registered at boot.
+//   the lowered-body door                → NOT a method here. [#22301] What a
+//     deployment runs for a hook or an action is the `body` `objectstack
+//     build` lowered its function to, in the runtime's QuickJS sandbox. Which
+//     of the two runs is decided by the app the boot mounts, so the door is a
+//     boot option, `bootStack(config, { artifact })`: the compiled artifact is
+//     mounted as the app, and every door above then runs its bodies. The
+//     handle lowers nothing and runs no sandbox of its own.
+//     `harness.artifact-door.test.ts` pins the door, and
+//     `packages/qa/dogfood/test/lowered-body-door.dogfood.test.ts` pins a
+//     handler the build's real lowering turns into a body that refuses.
 //
 // ⛔ Design rule (hotcrm#1579 step 5a): if a method needs a semantic the
 // kernel does not expose, that is a kernel gap to FILE — never a semantic to