diff --git a/.changeset/23610-record-page-seed-default.md b/.changeset/23610-record-page-seed-default.md
new file mode 100644
index 0000000000..5c3efd4878
--- /dev/null
+++ b/.changeset/23610-record-page-seed-default.md
@@ -0,0 +1,14 @@
+---
+'@object-ui/plugin-detail': patch
+'@object-ui/types': patch
+---
+
+A new record page seeded in Studio is saved with the `default` layout template instead of `full-width`, and the page node's `template` member is typed by reference to the spec's (part of objectstack#23610).
+
+`@objectstack/spec` closes `PageSchema.template` to four layout names — `default`, `header-sidebar-main`, `three-column`, `dashboard` — and retires `full-width` by name, naming `default` as its replacement; the save path refuses a page that still carries it.
+
+- **`buildDefaultPageSchema` seeds `template: 'default'`.** Studio's "new record page" seed takes its template from this synthesis, so with the old value the first save of a new record page was refused. The renderer maps `default` and `full-width` to the same `FullWidthTemplate`, so a seeded page lays out exactly as before.
+- **`PageNodeSchema.template` is `SpecPage['template']`.** The member was re-declared as `string` over the spec's inherited one; once the spec closes the set, that widening is a TypeScript error (TS2430) on the interface. Against today's spec, whose member is still `string`, the type is unchanged.
+- **The zod mirror's `template` is the spec's member too.** `PageNodeSchema` in the zod face declared `template: z.string()`, which accepts every name; once the spec closes the set it measures wider than the TS face, so `full-width` would still pass `objectui validate`. It now takes the spec's own member (defaults stripped, as for every imported member), and against today's spec it accepts exactly what it accepted before.
+
+The renderer still recognises `full-width`, so pages already stored with it keep rendering.
diff --git a/packages/app-shell/src/utils/__tests__/pageSchemaIntrospect.test.ts b/packages/app-shell/src/utils/__tests__/pageSchemaIntrospect.test.ts
index 79d20e58b9..db0ad764b3 100644
--- a/packages/app-shell/src/utils/__tests__/pageSchemaIntrospect.test.ts
+++ b/packages/app-shell/src/utils/__tests__/pageSchemaIntrospect.test.ts
@@ -82,7 +82,7 @@ describe('stripDiscussionNodes', () => {
       type: 'record',
       pageType: 'record',
       object: 'account',
-      template: 'full-width',
+      template: 'default',
       regions: [
         {
           name: 'main',
@@ -99,7 +99,7 @@ describe('stripDiscussionNodes', () => {
     expect(types(stripped)).toEqual(['record', 'page:header', 'page:tabs', 'page:tab']);
     // Everything else about the page survives, including the scalars that are
     // not nodes at all.
-    expect(stripped.template).toBe('full-width');
+    expect(stripped.template).toBe('default');
     expect(stripped.regions[0].name).toBe('main');
     expect(stripped.regions[0].width).toBe('full');
   });
diff --git a/packages/plugin-detail/src/synth/__tests__/buildDefaultPageSchema.test.ts b/packages/plugin-detail/src/synth/__tests__/buildDefaultPageSchema.test.ts
index 771e3d3561..dc326dd77c 100644
--- a/packages/plugin-detail/src/synth/__tests__/buildDefaultPageSchema.test.ts
+++ b/packages/plugin-detail/src/synth/__tests__/buildDefaultPageSchema.test.ts
@@ -201,12 +201,13 @@ describe('deriveHighlightFields', () => {
 });
 
 describe('buildDefaultPageSchema', () => {
-  it('emits a record Page with full-width template + main region', () => {
+  it('emits a record Page with the default template + main region', () => {
     const page = buildDefaultPageSchema(leadDef);
     expect(page.type).toBe('record');
     expect(page.pageType).toBe('record');
     expect(page.object).toBe('lead');
-    expect(page.template).toBe('full-width');
+    // The spec retires `full-width` by name; a seed carrying it is refused at save.
+    expect(page.template).toBe('default');
     expect(page.regions).toHaveLength(1);
     expect(page.regions[0].name).toBe('main');
   });
diff --git a/packages/plugin-detail/src/synth/buildDefaultPageSchema.ts b/packages/plugin-detail/src/synth/buildDefaultPageSchema.ts
index bc4939b76c..727bb7a7c8 100644
--- a/packages/plugin-detail/src/synth/buildDefaultPageSchema.ts
+++ b/packages/plugin-detail/src/synth/buildDefaultPageSchema.ts
@@ -989,7 +989,7 @@ export function buildDefaultAttachments(): any {
  * page.
  *
  * Shape:
- *   { type:'record', template:'full-width', regions:[ { name:'main',
+ *   { type:'record', template:'default', regions:[ { name:'main',
  *     components: [page:header, record:highlights?, record:path?,
  *     page:tabs, record:discussion?] } ] }
  *   For `enable.files: true` objects the tabs node carries a peer
@@ -1172,7 +1172,11 @@ export function buildDefaultPageSchema(
     type: 'record',
     pageType: 'record',
     object: def?.name,
-    template: 'full-width',
+    // `default`, not `full-width`: the spec's `PageSchema.template` names four
+    // layouts and retires `full-width` by name (its replacement is `default`),
+    // so a Studio seed carrying it is refused at save. The renderer maps both
+    // names to the same `FullWidthTemplate`, so the seed lays out unchanged.
+    template: 'default',
     regions,
   };
 }
diff --git a/packages/types/src/layout.ts b/packages/types/src/layout.ts
index 89b76bcc5e..a6831f0d17 100644
--- a/packages/types/src/layout.ts
+++ b/packages/types/src/layout.ts
@@ -1643,8 +1643,13 @@ export interface PageNodeSchema extends BaseSchema, Omit<SpecPage, (typeof PAGE_
    * `FullWidthTemplate`, the zod mirror's `.default('default')` made a PARSED
    * page take the template branch and skip the `pageType` dispatch entirely —
    * one authored page, two layouts. objectui#7735 removed the substitution.
+   *
+   * Typed by reference to the spec's member, so the closed set of layout
+   * names the spec declares is the set this node accepts — a re-declared
+   * `string` widens the inherited member, which TypeScript refuses once the
+   * spec closes it.
    */
-  template?: string;
+  template?: SpecPage['template'];
   /**
    * Local page state variables
    * Initialized on mount and available to all components via context
diff --git a/packages/types/src/zod/layout.zod.ts b/packages/types/src/zod/layout.zod.ts
index 4abfe12444..bd56d5345c 100644
--- a/packages/types/src/zod/layout.zod.ts
+++ b/packages/types/src/zod/layout.zod.ts
@@ -1305,7 +1305,12 @@ export const PageNodeSchema = BaseSchema.extend(SpecPageFields.shape).extend({
     .optional()
     .describe('Page override mode (full | slotted | html | react)'),
   object: z.string().optional().describe('Bound object name (for record pages)'),
-  template: z.string().optional().describe('Layout template name'),
+  // objectstack#23610: the spec's own member, by reference, mirroring the TS
+  // face's `PageNodeSchema.template` (`SpecPage['template']`). A `z.string()`
+  // here accepts every name, so once the spec closes the set of layout names it
+  // measures WIDER than the TS face and accepts the `full-width` the spec
+  // retires. Against a spec whose member is still a string, it is unchanged.
+  template: stripImportedDefaults(SpecPageSchema).shape.template.describe('Layout template name'),
   variables: z.array(PageVariableSchema).optional().describe('Local page state variables'),
   regions: z.array(PageNodeRegionSchema).optional().describe('Page layout regions'),
   body: aliasKeyRefusal(