diff --git a/packages/dogfood/test/package-first-authoring.dogfood.test.ts b/packages/dogfood/test/package-first-authoring.dogfood.test.ts
new file mode 100644
index 0000000000..55e7ed4130
--- /dev/null
+++ b/packages/dogfood/test/package-first-authoring.dogfood.test.ts
@@ -0,0 +1,59 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+//
+// GOLDEN REGRESSION — ADR-0070 package-first authoring, exercised end-to-end
+// through the real booted stack (not a mocked unit). The kernel must REJECT a
+// runtime-only create that targets a read-only code/installed package with
+// `writable_package_required` (D1/D2) instead of silently coercing it to a
+// package-less orphan (the pre-ADR #2252 behavior). This is the contract the
+// Studio + AI surfaces rely on as the backstop.
+//
+// Reverting D1 (the writable_package_required throw in saveMetaItem) turns this
+// red — that is the point of the gate.
+
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import crmStack from '@objectstack/example-crm';
+import { bootStack, type VerifyStack } from '@objectstack/verify';
+
+describe('dogfood: package-first authoring rejects runtime creates into read-only packages (ADR-0070 D1/D2)', () => {
+  let stack: VerifyStack;
+
+  beforeAll(async () => {
+    stack = await bootStack(crmStack);
+  });
+  afterAll(async () => {
+    await stack?.stop?.();
+  });
+
+  it('saveMetaItem(runtime-only) into a loaded code package throws writable_package_required', async () => {
+    // The objectql engine records every booted code package in its manifest map;
+    // any one of them is a read-only authoring target (isWritablePackage=false).
+    const ql = await stack.kernel.getServiceAsync<any>('objectql');
+    const manifests = (ql?.manifests ?? ql?.engine?.manifests) as Map<string, unknown> | undefined;
+    const codePkgId = manifests && typeof manifests.keys === 'function' ? [...manifests.keys()][0] : undefined;
+    expect(codePkgId, 'expected at least one loaded code package in the booted stack').toBeTruthy();
+
+    const protocol = await stack.kernel.getServiceAsync<any>('protocol');
+    await expect(
+      protocol.saveMetaItem({
+        type: 'object',
+        name: 'dogfood_pkgfirst_probe',
+        item: { name: 'dogfood_pkgfirst_probe', label: 'Probe', fields: { name: { type: 'text', label: 'Name' } } },
+        packageId: codePkgId,
+        mode: 'draft',
+      }),
+    ).rejects.toMatchObject({ code: 'writable_package_required' });
+  });
+
+  it('the same create into a fresh writable base id is NOT rejected (control)', async () => {
+    const protocol = await stack.kernel.getServiceAsync<any>('protocol');
+    // A bare, unregistered project-base id is writable — the write must succeed.
+    const res = await protocol.saveMetaItem({
+      type: 'object',
+      name: 'dogfood_pkgfirst_ok',
+      item: { name: 'dogfood_pkgfirst_ok', label: 'OK', fields: { name: { type: 'text', label: 'Name' } } },
+      packageId: 'app.dogfood_probe_base',
+      mode: 'draft',
+    });
+    expect(res?.success ?? true).toBeTruthy();
+  });
+});