diff --git a/.changeset/adr-0070-d4-duplicate-package.md b/.changeset/adr-0070-d4-duplicate-package.md
new file mode 100644
index 0000000000..fedba8b173
--- /dev/null
+++ b/.changeset/adr-0070-d4-duplicate-package.md
@@ -0,0 +1,18 @@
+---
+"@objectstack/objectql": patch
+"@objectstack/runtime": patch
+---
+
+feat(objectql): duplicate a writable base — ADR-0070 D4 ("duplicate base")
+
+`protocol.duplicatePackage` clones every ACTIVE item a base owns into a NEW
+package, **re-namespacing** object names (the blueprint prefixes a base's object
+names with its namespace, e.g. `iojn_repair_ticket`, and `sys_metadata` keys on
+`(type,name,org)` so a same-name copy would collide with the source) and
+**rewriting every intra-package reference** (lookup `reference`, view `object`,
+expressions, …) to the new names via a longest-first, identifier-boundary
+replace. Exposed as `POST /packages/:id/duplicate` (body
+`{ targetPackageId, targetName?, targetNamespace? }`).
+
+Completes ADR-0070 D4 (package = lifecycle unit): delete-cascade and export
+already shipped; this adds the duplicate gesture.
diff --git a/packages/objectql/src/protocol-package-lifecycle.test.ts b/packages/objectql/src/protocol-package-lifecycle.test.ts
index 2504885347..11cd5baca8 100644
--- a/packages/objectql/src/protocol-package-lifecycle.test.ts
+++ b/packages/objectql/src/protocol-package-lifecycle.test.ts
@@ -103,3 +103,77 @@ describe('protocol.deletePackage', () => {
         expect(res).toMatchObject({ success: false, deletedCount: 0 });
     });
 });
+
+describe('protocol.duplicatePackage (ADR-0070 D4)', () => {
+    function makeProtocol() {
+        const rows = [
+            {
+                type: 'object', name: 'iojn_repair_ticket', state: 'active',
+                metadata: JSON.stringify({
+                    name: 'iojn_repair_ticket', label: 'Ticket',
+                    fields: { title: { type: 'text' }, customer: { type: 'lookup', reference: 'iojn_customer' } },
+                }),
+            },
+            {
+                type: 'object', name: 'iojn_customer', state: 'active',
+                metadata: JSON.stringify({ name: 'iojn_customer', label: 'Customer', fields: { full_name: { type: 'text' } } }),
+            },
+            {
+                type: 'view', name: 'iojn_repair_ticket.all', state: 'active',
+                metadata: JSON.stringify({ name: 'iojn_repair_ticket.all', object: 'iojn_repair_ticket', viewKind: 'list' }),
+            },
+        ];
+        const installPackage = vi.fn();
+        const engine = {
+            find: vi.fn(async () => rows),
+            registry: {
+                getPackage: vi.fn(() => ({
+                    manifest: { id: 'app.iojn', name: 'Repair', namespace: 'iojn', version: '1.0.0', type: 'application', scope: 'environment' },
+                })),
+                installPackage,
+            },
+        };
+        const protocol = new ObjectStackProtocolImplementation(engine as never);
+        const saveMetaItem = vi.spyOn(protocol, 'saveMetaItem' as never);
+        (saveMetaItem as any).mockResolvedValue({ success: true } as never);
+        return { protocol, saveMetaItem, installPackage };
+    }
+
+    it('clones items into a new package, re-namespacing names AND rewriting references', async () => {
+        const { protocol, saveMetaItem, installPackage } = makeProtocol();
+        const res = await protocol.duplicatePackage({
+            sourcePackageId: 'app.iojn', targetPackageId: 'app.iojn2', targetNamespace: 'iojn2',
+        });
+
+        // target package installed as a writable copy (new id + namespace, scope kept)
+        expect(installPackage).toHaveBeenCalledWith(
+            expect.objectContaining({ id: 'app.iojn2', namespace: 'iojn2', scope: 'environment' }),
+        );
+
+        const calls = (saveMetaItem as any).mock.calls.map((c: any) => c[0]);
+        const ticket = calls.find((c: any) => c.name === 'iojn2_repair_ticket');
+        const customer = calls.find((c: any) => c.name === 'iojn2_customer');
+        const view = calls.find((c: any) => c.name === 'iojn2_repair_ticket.all');
+
+        expect(ticket).toBeTruthy();
+        expect(ticket.packageId).toBe('app.iojn2');
+        expect(ticket.mode).toBe('publish');
+        // the lookup reference was rewritten to the cloned object's new name
+        expect(ticket.item.fields.customer.reference).toBe('iojn2_customer');
+        expect(ticket.item.name).toBe('iojn2_repair_ticket');
+        expect(customer).toBeTruthy();
+        // the view's object binding + name were re-namespaced too
+        expect(view.item.object).toBe('iojn2_repair_ticket');
+
+        expect(res).toMatchObject({ success: true, copiedCount: 3, failedCount: 0, targetPackageId: 'app.iojn2' });
+    });
+
+    it('does NOT rewrite a same-prefix-but-distinct token incorrectly (boundary-safe)', async () => {
+        const { protocol, saveMetaItem } = makeProtocol();
+        await protocol.duplicatePackage({ sourcePackageId: 'app.iojn', targetPackageId: 'app.iojn2', targetNamespace: 'iojn2' });
+        const calls = (saveMetaItem as any).mock.calls.map((c: any) => c[0]);
+        // iojn_customer → iojn2_customer (exact), never iojn2_customer-with-leftover
+        expect(calls.some((c: any) => c.name === 'iojn2_customer')).toBe(true);
+        expect(calls.some((c: any) => /iojn_/.test(c.name))).toBe(false); // no un-renamed leftovers
+    });
+});
diff --git a/packages/objectql/src/protocol.ts b/packages/objectql/src/protocol.ts
index 5a0ea0f810..9b7dd3171e 100644
--- a/packages/objectql/src/protocol.ts
+++ b/packages/objectql/src/protocol.ts
@@ -4464,6 +4464,122 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
         };
     }
 
+    /**
+     * ADR-0070 D4 — duplicate a writable base into a NEW package (the Airtable
+     * "duplicate base" gesture). Clones every ACTIVE item the source owns into
+     * `targetPackageId`, RE-NAMESPACING object names — the blueprint prefixes a
+     * base's object names with its namespace (e.g. `iojn_repair_ticket`), and
+     * `sys_metadata` keys on (type,name,org), so a same-name copy would collide
+     * with the source — and rewriting every intra-package reference (lookup
+     * `reference`, view `object`, expressions, etc.) to the new names. Per-item
+     * best-effort; one failure never aborts the whole clone.
+     */
+    async duplicatePackage(request: {
+        sourcePackageId: string;
+        targetPackageId: string;
+        targetName?: string;
+        targetNamespace?: string;
+        organizationId?: string;
+        actor?: string;
+    }): Promise<{
+        success: boolean;
+        copiedCount: number;
+        failedCount: number;
+        targetPackageId: string;
+        copied: Array<{ type: string; name: string }>;
+        failed: Array<{ type: string; name: string; error: string }>;
+    }> {
+        const registry: any = (this.engine as any).registry;
+        const srcPkg = registry?.getPackage?.(request.sourcePackageId);
+        const sourceNs: string =
+            (srcPkg?.manifest?.namespace as string) ?? (request.sourcePackageId.split('.').pop() ?? '');
+        const targetNs: string =
+            request.targetNamespace ?? (request.targetPackageId.split('.').pop() ?? request.targetPackageId);
+
+        const where: Record<string, unknown> = { package_id: request.sourcePackageId, state: 'active' };
+        if (request.organizationId) where.organization_id = request.organizationId;
+        const rows = (await this.engine.find('sys_metadata', { where })) as any[];
+
+        // Map only OBJECT names that carry the source namespace prefix; views/etc.
+        // are renamed by the same prefix swap and reference-rewritten via the map.
+        const renameName = (name: string): string =>
+            sourceNs && typeof name === 'string' && name.startsWith(`${sourceNs}_`)
+                ? `${targetNs}_${name.slice(sourceNs.length + 1)}`
+                : name;
+        const renameMap = new Map<string, string>();
+        for (const row of rows) {
+            if (row?.type === 'object') {
+                const nn = renameName(row.name);
+                if (nn !== row.name) renameMap.set(row.name, nn);
+            }
+        }
+        // Longest-first, identifier-boundary rewrite so `iojn_task` never corrupts
+        // `iojn_task_log`, and `iojn_x` inside `record.iojn_x`/`iojn_x.view` matches.
+        const olds = [...renameMap.keys()].sort((a, b) => b.length - a.length);
+        const esc = (s: string) => s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+        const re = olds.length ? new RegExp(`(${olds.map(esc).join('|')})(?![A-Za-z0-9_])`, 'g') : null;
+        const deepRewrite = (v: any): any => {
+            if (typeof v === 'string') return re ? v.replace(re, (m) => renameMap.get(m) ?? m) : v;
+            if (Array.isArray(v)) return v.map(deepRewrite);
+            if (v && typeof v === 'object') {
+                const o: any = {};
+                for (const [k, val] of Object.entries(v)) o[k] = deepRewrite(val);
+                return o;
+            }
+            return v;
+        };
+
+        if (srcPkg?.manifest && typeof registry?.installPackage === 'function') {
+            try {
+                registry.installPackage({
+                    ...srcPkg.manifest,
+                    id: request.targetPackageId,
+                    name: request.targetName ?? `${srcPkg.manifest.name ?? request.sourcePackageId} (copy)`,
+                    namespace: targetNs,
+                });
+            } catch {
+                /* best-effort — the per-item package binding still works without a manifest row */
+            }
+        }
+
+        const copied: Array<{ type: string; name: string }> = [];
+        const failed: Array<{ type: string; name: string; error: string }> = [];
+        for (const row of rows) {
+            const newName = renameName(row.name);
+            let item: any;
+            try {
+                item = typeof row.metadata === 'string' ? JSON.parse(row.metadata) : (row.metadata ?? {});
+            } catch {
+                failed.push({ type: row.type, name: row.name, error: 'unparseable metadata' });
+                continue;
+            }
+            const rewritten = deepRewrite(item);
+            if (rewritten && typeof rewritten === 'object' && !Array.isArray(rewritten)) rewritten.name = newName;
+            try {
+                await this.saveMetaItem({
+                    type: row.type,
+                    name: newName,
+                    item: rewritten,
+                    mode: 'publish',
+                    packageId: request.targetPackageId,
+                    ...(request.organizationId ? { organizationId: request.organizationId } : {}),
+                    ...(request.actor ? { actor: request.actor } : {}),
+                });
+                copied.push({ type: row.type, name: newName });
+            } catch (e: any) {
+                failed.push({ type: row.type, name: row.name, error: e?.message ?? 'copy failed' });
+            }
+        }
+        return {
+            success: failed.length === 0 && copied.length > 0,
+            copiedCount: copied.length,
+            failedCount: failed.length,
+            targetPackageId: request.targetPackageId,
+            copied,
+            failed,
+        };
+    }
+
     // ─────────────────────────────────────────────────────────────────────
     // ADR-0067 — package-scoped commit history & rollback
     // ─────────────────────────────────────────────────────────────────────
diff --git a/packages/runtime/src/http-dispatcher.ts b/packages/runtime/src/http-dispatcher.ts
index d36de8c072..dae9ac59c5 100644
--- a/packages/runtime/src/http-dispatcher.ts
+++ b/packages/runtime/src/http-dispatcher.ts
@@ -1912,6 +1912,35 @@ export class HttpDispatcher {
                 return { handled: true, response: this.success(manifest) };
             }
 
+            // POST /packages/:id/duplicate → clone this base into a NEW writable
+            // package, re-namespacing objects + rewriting references (ADR-0070 D4
+            // "duplicate base"). Body { targetPackageId, targetName?, targetNamespace? }.
+            if (parts.length === 2 && parts[1] === 'duplicate' && m === 'POST') {
+                const id = decodeURIComponent(parts[0]);
+                const protocol = await this.resolveService('protocol');
+                if (!protocol || typeof (protocol as any).duplicatePackage !== 'function') {
+                    return { handled: true, response: this.error('Package duplication not supported', 501) };
+                }
+                const targetPackageId = typeof body?.targetPackageId === 'string' ? body.targetPackageId.trim() : '';
+                if (!targetPackageId) {
+                    return { handled: true, response: this.error('Body { targetPackageId } is required', 400) };
+                }
+                try {
+                    const organizationId = await this.resolveActiveOrganizationId(_context);
+                    const result = await (protocol as any).duplicatePackage({
+                        sourcePackageId: id,
+                        targetPackageId,
+                        ...(typeof body?.targetName === 'string' ? { targetName: body.targetName } : {}),
+                        ...(typeof body?.targetNamespace === 'string' ? { targetNamespace: body.targetNamespace } : {}),
+                        ...(organizationId ? { organizationId } : {}),
+                        ...(body?.actor ? { actor: body.actor } : {}),
+                    });
+                    return { handled: true, response: this.success(result) };
+                } catch (e: any) {
+                    return { handled: true, response: this.error(e.message, e.statusCode || 500) };
+                }
+            }
+
             // GET /packages/:id → get package
             if (parts.length === 1 && m === 'GET') {
                 const id = decodeURIComponent(parts[0]);