@@ -0,0 +1,11 @@
+---
+"@object-ui/plugin-gantt": patch
+"@object-ui/app-shell": patch
+---
+
+Clause-②: no
+Metadata-protocol: narrowed
+
+An invalid `gantt` block is refused instead of drawn (objectui#13459). `ObjectGantt` used to log `Invalid gantt configuration` and render the block anyway, so a block with a misspelt or missing key still drew a chart. It now renders a refusal that names each `GanttConfigSchema` issue by its path in the block (`gantt.endDateField: …`); a valid block and the flat ObjectView / ListView spelling render as before.
+
+The Studio designers' spec derivations (`dashboard`, `package`, `page`, `report` and `view` schemas in `metadata-admin`) no longer catch a failed derivation and return `undefined`, which rendered a designer form silently missing fields. Their only input is the bundled spec, so a failure is a build-time fact that fails their tests; at runtime it reaches the route's error boundary.
@@ -39,20 +39,19 @@ const FORM_FIELDS_OWNED_ELSEWHERE = new Set([
   'name', // record identity — not user-editable here
 ]);
 
+/**
+ * No `try`/`catch` around the spec derivations in this file (objectui#13459).
+ * Their only input is the bundled `@objectstack/spec`, so a derivation that
+ * fails is a build-time fact: the tests beside this file go red, and at runtime
+ * the throw reaches the route's error boundary. It used to be caught, warned
+ * about in the console and turned into `undefined`, which rendered a designer
+ * form silently missing fields that the author could then save past.
+ */
 let _dashboardDocSchema: JsonSchema | undefined;
-let _dashboardDocFailed = false;
 
 /** JSONSchema for the whole (flat) Dashboard document. */
-export function getDashboardSchema(): JsonSchema | undefined {
-  if (_dashboardDocSchema || _dashboardDocFailed) return _dashboardDocSchema;
-  try {
-    _dashboardDocSchema = z.toJSONSchema(DashboardSchema, TO_JSON_OPTS) as JsonSchema;
-  } catch (err) {
-    _dashboardDocFailed = true;
-    if (typeof console !== 'undefined') {
-      console.warn('[dashboard-schema] failed to derive Dashboard JSONSchema from spec', err);
-    }
-  }
+export function getDashboardSchema(): JsonSchema {
+  _dashboardDocSchema ??= z.toJSONSchema(DashboardSchema, TO_JSON_OPTS) as JsonSchema;
   return _dashboardDocSchema;
 }
 
@@ -79,31 +78,24 @@ export function getDashboardForm(locale?: SupportedLocale | string): FormViewSpe
   const cacheKey = String(locale ?? '');
   if (_dashboardForm.has(cacheKey)) return _dashboardForm.get(cacheKey);
   if (!specDashboardForm || typeof specDashboardForm !== 'object') return undefined;
-  try {
-    const clone = JSON.parse(JSON.stringify(specDashboardForm)) as FormViewSpec;
-    for (const section of clone.sections ?? []) {
-      section.fields = (section.fields ?? []).filter((f: any) => {
-        const name = typeof f === 'string' ? f : f?.field;
-        return !FORM_FIELDS_OWNED_ELSEWHERE.has(name);
-      });
-    }
-    // Drop now-empty sections so we don't render bare headers.
-    clone.sections = (clone.sections ?? []).filter(
-      (s: any) => (s.fields ?? []).length > 0,
-    );
-    // Localize AFTER pruning: the overlay only has to reach what renders, and
-    // pruning cannot drop a section the overlay just renamed.
-    const localized = localizeMetadataForm(
-      clone as unknown as Record<string, unknown>,
-      'dashboard',
-      locale,
-    ) as unknown as FormViewSpec;
-    _dashboardForm.set(cacheKey, localized);
-    return localized;
-  } catch (err) {
-    if (typeof console !== 'undefined') {
-      console.warn('[dashboard-schema] failed to prepare dashboardForm from spec', err);
-    }
-    return undefined;
+  const clone = JSON.parse(JSON.stringify(specDashboardForm)) as FormViewSpec;
+  for (const section of clone.sections ?? []) {
+    section.fields = (section.fields ?? []).filter((f: any) => {
+      const name = typeof f === 'string' ? f : f?.field;
+      return !FORM_FIELDS_OWNED_ELSEWHERE.has(name);
+    });
   }
+  // Drop now-empty sections so we don't render bare headers.
+  clone.sections = (clone.sections ?? []).filter(
+    (s: any) => (s.fields ?? []).length > 0,
+  );
+  // Localize AFTER pruning: the overlay only has to reach what renders, and
+  // pruning cannot drop a section the overlay just renamed.
+  const localized = localizeMetadataForm(
+    clone as unknown as Record<string, unknown>,
+    'dashboard',
+    locale,
+  ) as unknown as FormViewSpec;
+  _dashboardForm.set(cacheKey, localized);
+  return localized;
 }
@@ -50,20 +50,19 @@ export const PACKAGE_FORM_FIELDS = [
   'dependencies',
 ] as const;
 
+/**
+ * No `try`/`catch` around the spec derivations in this file (objectui#13459).
+ * Their only input is the bundled `@objectstack/spec`, so a derivation that
+ * fails is a build-time fact: the tests beside this file go red, and at runtime
+ * the throw reaches the route's error boundary. It used to be caught, warned
+ * about in the console and turned into `undefined`, which rendered a designer
+ * form silently missing fields that the author could then save past.
+ */
 let _schema: JsonSchema | undefined;
-let _schemaFailed = false;
 
 /** JSONSchema for the whole package manifest (memoised, spec-derived). */
-export function getPackageSchema(): JsonSchema | undefined {
-  if (_schema || _schemaFailed) return _schema;
-  try {
-    _schema = z.toJSONSchema(ManifestSchema, TO_JSON_OPTS) as JsonSchema;
-  } catch (err) {
-    _schemaFailed = true;
-    if (typeof console !== 'undefined') {
-      console.warn('[package-schema] failed to derive manifest JSONSchema from spec', err);
-    }
-  }
+export function getPackageSchema(): JsonSchema {
+  _schema ??= z.toJSONSchema(ManifestSchema, TO_JSON_OPTS) as JsonSchema;
   return _schema;
 }
 
 
@@ -39,20 +39,19 @@ const TO_JSON_OPTS = { io: 'input', unrepresentable: 'any' } as const;
  */
 export const PAGE_FIELDS_OWNED_ELSEWHERE = new Set(['name', 'regions', 'children']);
 
+/**
+ * No `try`/`catch` around the spec derivations in this file (objectui#13459).
+ * Their only input is the bundled `@objectstack/spec`, so a derivation that
+ * fails is a build-time fact: the tests beside this file go red, and at runtime
+ * the throw reaches the route's error boundary. It used to be caught, warned
+ * about in the console and turned into `undefined`, which rendered a designer
+ * form silently missing fields that the author could then save past.
+ */
 let _pageSchema: JsonSchema | undefined;
-let _pageSchemaFailed = false;
 
 /** JSONSchema for the whole Page document (memoised, spec-derived). */
-export function getPageSchema(): JsonSchema | undefined {
-  if (_pageSchema || _pageSchemaFailed) return _pageSchema;
-  try {
-    _pageSchema = z.toJSONSchema(PageSchema, TO_JSON_OPTS) as JsonSchema;
-  } catch (err) {
-    _pageSchemaFailed = true;
-    if (typeof console !== 'undefined') {
-      console.warn('[page-schema] failed to derive Page JSONSchema from spec', err);
-    }
-  }
+export function getPageSchema(): JsonSchema {
+  _pageSchema ??= z.toJSONSchema(PageSchema, TO_JSON_OPTS) as JsonSchema;
   return _pageSchema;
 }
 
@@ -67,21 +66,14 @@ let _pageForm: FormViewSpec | undefined;
 export function getPageForm(): FormViewSpec | undefined {
   if (_pageForm) return _pageForm;
   if (!specPageForm || typeof specPageForm !== 'object') return undefined;
-  try {
-    const clone = JSON.parse(JSON.stringify(specPageForm)) as FormViewSpec;
-    for (const section of clone.sections ?? []) {
-      section.fields = (section.fields ?? []).filter((f: any) => {
-        const name = typeof f === 'string' ? f : f?.field;
-        return !PAGE_FIELDS_OWNED_ELSEWHERE.has(name);
-      });
-    }
-    clone.sections = (clone.sections ?? []).filter((s) => (s.fields ?? []).length > 0);
-    _pageForm = clone;
-  } catch (err) {
-    if (typeof console !== 'undefined') {
-      console.warn('[page-schema] failed to prune Page authoring form from spec', err);
-    }
-    _pageForm = specPageForm as FormViewSpec;
+  const clone = JSON.parse(JSON.stringify(specPageForm)) as FormViewSpec;
+  for (const section of clone.sections ?? []) {
+    section.fields = (section.fields ?? []).filter((f: any) => {
+      const name = typeof f === 'string' ? f : f?.field;
+      return !PAGE_FIELDS_OWNED_ELSEWHERE.has(name);
+    });
   }
+  clone.sections = (clone.sections ?? []).filter((s) => (s.fields ?? []).length > 0);
+  _pageForm = clone;
   return _pageForm;
 }
@@ -38,20 +38,19 @@ const FORM_FIELDS_OWNED_ELSEWHERE = new Set([
   'name', // record identity — not user-editable here
 ]);
 
+/**
+ * No `try`/`catch` around the spec derivations in this file (objectui#13459).
+ * Their only input is the bundled `@objectstack/spec`, so a derivation that
+ * fails is a build-time fact: the tests beside this file go red, and at runtime
+ * the throw reaches the route's error boundary. It used to be caught, warned
+ * about in the console and turned into `undefined`, which rendered a designer
+ * form silently missing fields that the author could then save past.
+ */
 let _reportDocSchema: JsonSchema | undefined;
-let _reportDocFailed = false;
 
 /** JSONSchema for the whole (flat) Report document. */
-export function getReportSchema(): JsonSchema | undefined {
-  if (_reportDocSchema || _reportDocFailed) return _reportDocSchema;
-  try {
-    _reportDocSchema = z.toJSONSchema(ReportSchema, TO_JSON_OPTS) as JsonSchema;
-  } catch (err) {
-    _reportDocFailed = true;
-    if (typeof console !== 'undefined') {
-      console.warn('[report-schema] failed to derive Report JSONSchema from spec', err);
-    }
-  }
+export function getReportSchema(): JsonSchema {
+  _reportDocSchema ??= z.toJSONSchema(ReportSchema, TO_JSON_OPTS) as JsonSchema;
   return _reportDocSchema;
 }
 
@@ -80,48 +79,41 @@ let _reportForm: FormViewSpec | undefined;
 export function getReportForm(): FormViewSpec | undefined {
   if (_reportForm) return _reportForm;
   if (!specReportForm || typeof specReportForm !== 'object') return undefined;
-  try {
-    const clone = JSON.parse(JSON.stringify(specReportForm)) as FormViewSpec;
-    const schemaProps = getReportSchema()?.properties as Record<string, unknown> | undefined;
-    for (const section of clone.sections ?? []) {
-      section.fields = (section.fields ?? []).filter((f: any) => {
-        const name = typeof f === 'string' ? f : f?.field;
-        if (FORM_FIELDS_OWNED_ELSEWHERE.has(name)) return false;
-        // Schema-subset pass: drop form fields the schema no longer carries.
-        if (schemaProps && !(name in schemaProps)) return false;
-        return true;
-      });
-    }
-    if (schemaProps && 'runtimeFilter' in schemaProps) {
-      const declared = new Set<string>();
-      for (const s of clone.sections ?? []) {
-        for (const f of s.fields ?? []) {
-          declared.add(typeof f === 'string' ? f : (f as any)?.field);
-        }
-      }
-      if (!declared.has('runtimeFilter')) {
-        clone.sections = [
-          ...(clone.sections ?? []),
-          {
-            label: 'Filter',
-            description: 'Render-time scope filter, ANDed at query time.',
-            collapsible: true,
-            collapsed: true,
-            fields: [{ field: 'runtimeFilter', widget: 'json' }],
-          },
-        ];
+  const clone = JSON.parse(JSON.stringify(specReportForm)) as FormViewSpec;
+  const schemaProps = getReportSchema().properties as Record<string, unknown> | undefined;
+  for (const section of clone.sections ?? []) {
+    section.fields = (section.fields ?? []).filter((f: any) => {
+      const name = typeof f === 'string' ? f : f?.field;
+      if (FORM_FIELDS_OWNED_ELSEWHERE.has(name)) return false;
+      // Schema-subset pass: drop form fields the schema no longer carries.
+      if (schemaProps && !(name in schemaProps)) return false;
+      return true;
+    });
+  }
+  if (schemaProps && 'runtimeFilter' in schemaProps) {
+    const declared = new Set<string>();
+    for (const s of clone.sections ?? []) {
+      for (const f of s.fields ?? []) {
+        declared.add(typeof f === 'string' ? f : (f as any)?.field);
       }
     }
-    // Drop now-empty sections so we don't render bare headers.
-    clone.sections = (clone.sections ?? []).filter(
-      (s: any) => (s.fields ?? []).length > 0,
-    );
-    _reportForm = clone;
-  } catch (err) {
-    if (typeof console !== 'undefined') {
-      console.warn('[report-schema] failed to prepare reportForm from spec', err);
+    if (!declared.has('runtimeFilter')) {
+      clone.sections = [
+        ...(clone.sections ?? []),
+        {
+          label: 'Filter',
+          description: 'Render-time scope filter, ANDed at query time.',
+          collapsible: true,
+          collapsed: true,
+          fields: [{ field: 'runtimeFilter', widget: 'json' }],
+        },
+      ];
     }
-    return undefined;
   }
+  // Drop now-empty sections so we don't render bare headers.
+  clone.sections = (clone.sections ?? []).filter(
+    (s: any) => (s.fields ?? []).length > 0,
+  );
+  _reportForm = clone;
   return _reportForm;
 }
@@ -0,0 +1,73 @@
+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * objectui#13459 — the designer forms' spec derivations fail LOUDLY.
+ *
+ * The five `*-schema.ts` modules derive their JSONSchema from the bundled
+ * `@objectstack/spec`. That input is fixed at build time, so a derivation that
+ * fails is a build-time fact: this file goes red for it. At runtime the throw
+ * reaches the route's error boundary instead of being caught, warned about and
+ * turned into `undefined` — which used to render a designer form silently
+ * missing fields.
+ *
+ * Two halves: every derivation succeeds against the bundled spec, and a
+ * derivation that throws reaches the caller instead of becoming `undefined`.
+ */
+
+import { describe, it, expect, vi, afterEach } from 'vitest';
+
+const DERIVATIONS = [
+  ['dashboard-schema', 'getDashboardSchema'],
+  ['package-schema', 'getPackageSchema'],
+  ['page-schema', 'getPageSchema'],
+  ['report-schema', 'getReportSchema'],
+  ['view-schema', 'getListVariantSchema'],
+  ['view-schema', 'getFormVariantSchema'],
+  ['view-schema', 'getListColumnSchema'],
+] as const;
+
+const LOADERS: Record<(typeof DERIVATIONS)[number][0], () => Promise<unknown>> = {
+  'dashboard-schema': () => import('./dashboard-schema'),
+  'package-schema': () => import('./package-schema'),
+  'page-schema': () => import('./page-schema'),
+  'report-schema': () => import('./report-schema'),
+  'view-schema': () => import('./view-schema'),
+};
+
+/** A fresh module instance per case, so a memoised result cannot answer. */
+async function derive(file: (typeof DERIVATIONS)[number][0], getter: string): Promise<unknown> {
+  vi.resetModules();
+  const mod = (await LOADERS[file]()) as Record<string, () => unknown>;
+  return mod[getter]();
+}
+
+// `vi.doMock`, not a hoisted `vi.mock`: the failing `toJSONSchema` is scoped to
+// the cases that ask for it, and undone after each, so it cannot reach another
+// test file sharing this worker's module registry.
+afterEach(() => {
+  vi.doUnmock('zod');
+  vi.resetModules();
+});
+
+describe('designer spec derivations (objectui#13459)', () => {
+  it.each(DERIVATIONS)('%s.%s derives an object schema from the bundled spec', async (file, getter) => {
+    const schema = (await derive(file, getter)) as { type?: unknown; properties?: unknown } | undefined;
+    expect(schema).toBeDefined();
+    expect(schema?.type).toBe('object');
+    expect(schema?.properties).toBeTypeOf('object');
+  });
+
+  it.each(DERIVATIONS)('%s.%s throws when the derivation fails, never returns undefined', async (file, getter) => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    vi.doMock('zod', async (importOriginal) => {
+      const actual = await importOriginal<typeof import('zod')>();
+      const toJSONSchema = (): never => {
+        throw new Error('derivation failed (test)');
+      };
+      return { ...actual, z: { ...actual.z, toJSONSchema } };
+    });
+    await expect(derive(file, getter)).rejects.toThrow('derivation failed (test)');
+    expect(warn).not.toHaveBeenCalled();
+    warn.mockRestore();
+  });
+});