@@ -0,0 +1,11 @@
+---
+'@object-ui/app-shell': patch
+---
+
+The External Datasource panel in Setup and Studio reads the `{ success, data }` envelope its routes answer (objectui#11628). On a federated datasource such as the showcase's `showcase_external`, the Tables tab listed no remote tables. "Refresh catalog" showed no snapshot time, and "Run validation" replaced the panel with a render error (`Cannot read properties of undefined (reading 'length')`). Because the list was empty, the import dialog could not be opened. The client read `tables`, `draft`, `catalog` and the validation verdict from the top of the body, but the server puts each one under `data`. The panel now lists the remote tables, shows the snapshot time after a refresh, renders the validation rows, and opens the import dialog on the generated draft.
+
+Refusals on these routes now reach the user. Every refusal used to read `[object Object]`, because the client turned the ADR-0112 `{ error: { code, message } }` object into a string. That covered a missing capability, an unknown remote table, an unreachable datasource, and a capability refusal from "Import as Object". The panel now shows the server's message and code. The "federation is not enabled on this server" hint now appears when the server answers `503 SERVICE_UNAVAILABLE`. Before, it never did, because the client compared against a code the server no longer sends.
+
+A successful response that is not the `{ success: true, data }` envelope is now an error that names the route. Before, the panel showed it as an empty list.
+
+**Clause-②: no.** Nothing is added to or removed from the package entry. The changed module is not exported from it.
@@ -4,14 +4,15 @@ import { afterEach, describe, expect, it, vi } from 'vitest';
 import {
   listRemoteTables,
   generateObjectDraft,
+  refreshCatalog,
   validateDatasource,
   importObjectDraft,
   ExternalServiceUnavailableError,
   type ObjectDraft,
 } from './api';
 
 /**
- * Build a minimal Response-like object the client's `jsonOrThrow` accepts.
+ * Build a minimal Response-like object the client's readers accept.
  *
  * `headers` is real (objectui#4467): these calls go out through
  * `createAuthenticatedFetch`, which reads `set-auth-token` off every API
@@ -32,6 +33,22 @@ function jsonResponse(body: unknown, init: { status?: number; ok?: boolean } = {
   } as unknown as Response;
 }
 
+/*
+ * The WIRE shapes of the five `/datasources/:name/external/*` routes
+ * (objectui#11628). Every body there is written by the shared `sendOk` /
+ * `sendError` of `@objectstack/types` (`registerExternalDatasourceRoutes` in
+ * `@objectstack/rest`): a success is `{ success: true, data }` with the
+ * route's payload one level down, and a refusal is the ADR-0112 envelope
+ * `{ success: false, error: { code, message } }`.
+ *
+ * These fixtures used to be the BARE payloads (`{ tables }`, `{ draft }`, a
+ * string `error`), which is the shape the client read and the server never
+ * sent — so this file stayed green while the live panel listed no tables,
+ * showed no catalog timestamp and crashed on Validation.
+ */
+const ok = (data: unknown) => ({ success: true, data });
+const refusal = (code: string, message: string) => ({ success: false, error: { code, message } });
+
 function stubFetch(impl: (url: string, init?: RequestInit) => Response | Promise<Response>) {
   const spy = vi.fn(async (input: RequestInfo | URL, init?: RequestInit) =>
     impl(typeof input === 'string' ? input : String(input), init),
@@ -46,50 +63,154 @@ afterEach(() => {
 });
 
 describe('external datasource api', () => {
-  it('lists remote tables and unwraps the { tables } envelope', async () => {
+  it('lists remote tables out of the { success, data: { tables } } envelope', async () => {
     const spy = stubFetch(() =>
-      jsonResponse({ tables: [{ schema: 'public', name: 'orders', columnCount: 7 }] }),
+      jsonResponse(
+        ok({
+          tables: [
+            { name: 'customers', columnCount: 7 },
+            { name: 'orders', columnCount: 7 },
+          ],
+        }),
+      ),
     );
-    const tables = await listRemoteTables('warehouse');
-    expect(tables).toEqual([{ schema: 'public', name: 'orders', columnCount: 7 }]);
+    const tables = await listRemoteTables('showcase_external');
+    expect(tables).toEqual([
+      { name: 'customers', columnCount: 7 },
+      { name: 'orders', columnCount: 7 },
+    ]);
     const url = String(spy.mock.calls[0][0]);
-    expect(url).toContain('/api/v1/datasources/warehouse/external/tables');
+    expect(url).toContain('/api/v1/datasources/showcase_external/external/tables');
   });
 
   it('passes the ?schema filter through', async () => {
-    const spy = stubFetch(() => jsonResponse({ tables: [] }));
-    await listRemoteTables('warehouse', { schema: 'analytics' });
+    const spy = stubFetch(() => jsonResponse(ok({ tables: [] })));
+    await expect(listRemoteTables('warehouse', { schema: 'analytics' })).resolves.toEqual([]);
     expect(String(spy.mock.calls[0][0])).toContain('tables?schema=analytics');
   });
 
-  it('maps 503 external_service_unavailable to a typed error', async () => {
-    stubFetch(() => jsonResponse({ error: 'external_service_unavailable' }, { status: 503, ok: false }));
-    await expect(listRemoteTables('warehouse')).rejects.toBeInstanceOf(
-      ExternalServiceUnavailableError,
-    );
-  });
-
-  it('surfaces a generic server error message', async () => {
-    stubFetch(() => jsonResponse({ error: 'boom' }, { status: 500, ok: false }));
-    await expect(validateDatasource('warehouse')).rejects.toThrow('boom');
-  });
-
-  it('POSTs draft generation with the remote schema option', async () => {
+  it('POSTs draft generation with the remote schema option and reads data.draft', async () => {
     const spy = stubFetch(() =>
-      jsonResponse({
-        draft: { name: 'orders', datasource: 'warehouse', definition: {}, source: '', review: [] },
-      }),
+      jsonResponse(
+        ok({
+          draft: { name: 'orders', datasource: 'warehouse', definition: {}, source: '', review: [] },
+        }),
+      ),
     );
     const draft = await generateObjectDraft('warehouse', 'orders', { remoteSchema: 'public' });
     expect(draft.name).toBe('orders');
+    expect(draft.review).toEqual([]);
     const [url, init] = spy.mock.calls[0];
     expect(String(url)).toContain('/external/tables/orders/draft');
     expect(init?.method).toBe('POST');
     expect(JSON.parse(String(init?.body))).toEqual({ remoteSchema: 'public' });
   });
 
+  it('refreshes the catalog and reads data.catalog, snapshotAt included', async () => {
+    const catalog = {
+      name: 'showcase_external_catalog',
+      datasource: 'showcase_external',
+      snapshotAt: '2026-10-05T02:00:00.000Z',
+      tables: [],
+    };
+    const spy = stubFetch(() => jsonResponse(ok({ catalog })));
+    const got = await refreshCatalog('showcase_external');
+    expect(got).toEqual(catalog);
+    expect(got.snapshotAt).toBe('2026-10-05T02:00:00.000Z');
+    const [url, init] = spy.mock.calls[0];
+    expect(String(url)).toContain('/datasources/showcase_external/external/refresh-catalog');
+    expect(init?.method).toBe('POST');
+  });
+
+  it('validates and reads the { ok, results } verdict out of data', async () => {
+    const results = [
+      { object: 'showcase_ext_customer', ok: true, diffs: [] },
+      { object: 'showcase_ext_order', ok: true, diffs: [] },
+    ];
+    const spy = stubFetch(() => jsonResponse(ok({ ok: true, results })));
+    const report = await validateDatasource('showcase_external');
+    expect(report).toEqual({ ok: true, results });
+    expect(report.results).toHaveLength(2);
+    const [url, init] = spy.mock.calls[0];
+    expect(String(url)).toContain('/datasources/showcase_external/external/validate');
+    expect(init?.method).toBe('POST');
+  });
+
+  it('refuses a 200 that is not the declared envelope instead of reading it as empty', async () => {
+    // The bare payload this file used to mock. Read through the old client it
+    // was "no tables"; it is not a body these routes send, so it is a loud
+    // failure naming the route rather than an empty list.
+    stubFetch(() => jsonResponse({ tables: [{ name: 'orders', columnCount: 7 }] }));
+    const err = await listRemoteTables('warehouse').then(
+      () => null,
+      (e: unknown) => e,
+    );
+    expect(err).toBeInstanceOf(Error);
+    expect(err).not.toBeInstanceOf(ExternalServiceUnavailableError);
+    expect((err as Error).message).toContain('/external/tables');
+  });
+
+  it.each([
+    ['listRemoteTables', () => listRemoteTables('warehouse')],
+    ['generateObjectDraft', () => generateObjectDraft('warehouse', 'orders')],
+    ['refreshCatalog', () => refreshCatalog('warehouse')],
+    ['validateDatasource', () => validateDatasource('warehouse')],
+  ])('%s maps 503 SERVICE_UNAVAILABLE to the typed error', async (_name, call) => {
+    stubFetch(() =>
+      jsonResponse(
+        refusal('SERVICE_UNAVAILABLE', 'The external-datasource service is not available.'),
+        { status: 503 },
+      ),
+    );
+    await expect(call()).rejects.toBeInstanceOf(ExternalServiceUnavailableError);
+  });
+
+  it('surfaces the refusal envelope message and code, never "[object Object]"', async () => {
+    stubFetch(() =>
+      jsonResponse(refusal('EXTERNAL_DATASOURCE_ERROR', 'no such schema: analytics'), {
+        status: 400,
+      }),
+    );
+    const err = await validateDatasource('warehouse').then(
+      () => null,
+      (e: unknown) => e,
+    );
+    expect(err).toBeInstanceOf(Error);
+    expect(err).not.toBeInstanceOf(ExternalServiceUnavailableError);
+    expect((err as Error).message).not.toContain('[object Object]');
+    expect((err as Error).message).toContain('no such schema: analytics');
+    expect((err as Error).message).toContain('EXTERNAL_DATASOURCE_ERROR');
+  });
+
+  it('a 503 whose envelope names another code is not read as "federation not wired"', async () => {
+    stubFetch(() => jsonResponse(refusal('INTERNAL_ERROR', 'Internal server error'), { status: 503 }));
+    const err = await listRemoteTables('warehouse').then(
+      () => null,
+      (e: unknown) => e,
+    );
+    expect(err).toBeInstanceOf(Error);
+    expect(err).not.toBeInstanceOf(ExternalServiceUnavailableError);
+    expect((err as Error).message).toContain('INTERNAL_ERROR');
+  });
+
+  it('falls back to the HTTP status when a failure carries no readable body', async () => {
+    stubFetch(() => ({
+      ok: false,
+      status: 502,
+      statusText: 'Bad Gateway',
+      headers: new Headers(),
+      json: async () => {
+        throw new SyntaxError('Unexpected token <');
+      },
+    }) as unknown as Response);
+    await expect(refreshCatalog('warehouse')).rejects.toThrow('502 Bad Gateway');
+  });
+
   it('imports a draft as an object via PUT /meta/object/:name', async () => {
-    const spy = stubFetch(() => jsonResponse({ ok: true }));
+    // The `/meta` door's own success body — the save result, no `data`.
+    const spy = stubFetch(() =>
+      jsonResponse({ success: true, version: 'v1', seq: 1, state: 'active', message: 'Saved' }),
+    );
     const draft: ObjectDraft = {
       name: 'orders',
       datasource: 'warehouse',
@@ -103,4 +224,54 @@ describe('external datasource api', () => {
     expect(init?.method).toBe('PUT');
     expect(JSON.parse(String(init?.body))).toEqual({ name: 'orders', label: 'Orders' });
   });
+
+  /*
+   * The `/meta` door answers a refused save in two dialects, both measured
+   * live: the capability gate's nested `{ error: { code, message } }` and the
+   * spec-validation flat `{ error: '<sentence>', code }`.
+   */
+  const importDraft: ObjectDraft = {
+    name: 'orders',
+    datasource: 'warehouse',
+    definition: { name: 'orders', label: 'Orders' },
+    source: '',
+    review: [],
+  };
+
+  it('surfaces the /meta capability refusal (nested error) instead of "[object Object]"', async () => {
+    stubFetch(() =>
+      jsonResponse(
+        {
+          error: {
+            code: 'FORBIDDEN',
+            message: 'Saving a metadata item requires the `manage_metadata` capability.',
+          },
+        },
+        { status: 403 },
+      ),
+    );
+    const err = await importObjectDraft(importDraft).then(
+      () => null,
+      (e: unknown) => e,
+    );
+    expect(err).toBeInstanceOf(Error);
+    expect((err as Error).message).not.toContain('[object Object]');
+    expect((err as Error).message).toContain('manage_metadata');
+    expect((err as Error).message).toContain('FORBIDDEN');
+  });
+
+  it('surfaces the /meta spec-validation refusal (flat string error)', async () => {
+    stubFetch(() =>
+      jsonResponse(
+        {
+          error: 'object/orders failed spec validation: 1 issue — fields [invalid_type]',
+          code: 'INVALID_METADATA',
+        },
+        { status: 422 },
+      ),
+    );
+    await expect(importObjectDraft(importDraft)).rejects.toThrow(
+      'object/orders failed spec validation',
+    );
+  });
 });