diff --git a/.changeset/record-details-sections-object-form.md b/.changeset/record-details-sections-object-form.md
new file mode 100644
index 0000000000..8eac674a88
--- /dev/null
+++ b/.changeset/record-details-sections-object-form.md
@@ -0,0 +1,56 @@
+---
+"@objectstack/spec": minor
+---
+
+feat(spec)!: `RecordDetailsProps.sections` declares the object form every page actually authors, and `hideFields` is declared (#5611)
+
+`record:details` declared a `sections` shape that nothing produced and nothing
+consumed, and omitted a key a published platform page depends on. Both are now
+declared as delivered.
+
+**BREAKING (authored metadata shape) — `sections` is an object array, not an ID list.**
+
+```ts
+// FROM — declared, but written by zero pages and read by zero renderers
+sections: ['overview', 'financials']
+
+// TO — what every real page already authors
+sections: [
+  { label: 'Overview', columns: 2, fields: ['name', 'account', 'owner'] },
+  { label: 'Financials', columns: 2, fields: ['budget', 'spent'] },
+]
+```
+
+One-line fix: replace each section ID with `{ fields: [...] }`, naming the
+fields that section should render (add `label` for a heading, `columns` for its
+grid width, `name` to make the heading translatable).
+
+**Why this is safe despite being a type change — it was measured, not assumed.**
+The ID-list form had **zero** read paths and **zero** producers:
+
+- `objectui`'s `RecordDetailsRenderer` maps every `sections` entry as an object
+  (`s.name` / `s.label` / `s.title` / `s.fields`) and has no string branch — a
+  string entry would spread into a character map and render nothing;
+- `@object-ui/types`' `RecordDetailsComponentProps` mirror already declared
+  `Array<{ name?, label?, fields, ... }>`, and the Studio block designer can only
+  author `{ label, columns, fields }`;
+- every page in this repo authors the object form — three showcase pages
+  (`project-detail`, `task-detail`, `settings`) and the `sys_user` platform page;
+- `packages/lint` has modelled it as `nestedSections` (`sections[].fields[]`) all
+  along.
+
+So the "breakage" applies only to hypothetical stored metadata written against a
+declaration nothing ever honoured, and schema validation runs on the publish
+path — it does not rewrite data at rest.
+
+**New: `hideFields`.** `z.array(z.string()).optional()` — field names omitted
+from the body, applied to `fields` and to every section's `fields`. The
+`sys_user` platform page has authored it since it shipped and the renderer reads
+it; it was undeclared, so it survived only because per-component `properties` is
+never parsed. Declaring it now means the parse gate (#5068) preserves it instead
+of silently stripping a live page's hidden-field list.
+
+**Section keys**, each declared because it is delivered end to end:
+`fields` (required), `label`, `columns` (1-4), and `name` — the i18n anchor that
+resolves `objects.<object>._sections.<name>.label`, which `packages/lint`'s
+`translation-section-name-missing` rule tells authors to add.
diff --git a/content/docs/references/ui/component.mdx b/content/docs/references/ui/component.mdx
index d342317cb9..1856be8c7d 100644
--- a/content/docs/references/ui/component.mdx
+++ b/content/docs/references/ui/component.mdx
@@ -291,8 +291,9 @@ const result = AIChatWindowProps.parse(data);
 | :--- | :--- | :--- | :--- |
 | **columns** | `Enum<'1' \| '2' \| '3' \| '4'>` | ✅ | Number of columns for field layout (1-4) |
 | **layout** | `Enum<'auto' \| 'custom'>` | ✅ | Layout mode: auto uses object highlightFields, custom uses explicit sections |
-| **sections** | `string[]` | optional | Section IDs to show (required when layout is "custom") |
+| **sections** | `{ name?: string; label?: string; columns?: integer; fields: string[] }[]` | optional | Field groups rendered as the detail body, in order. Object form: `{ name?, label?, columns?, fields }`. |
 | **fields** | `string[]` | optional | Explicit field list to display (optional, overrides highlightFields) |
+| **hideFields** | `string[]` | optional | Field names to omit from the body — applied to `fields` and to every section's `fields` (used to dedupe fields already shown in `record:highlights` or as the page title) |
 | **aria** | `{ ariaLabel?: string; ariaDescribedBy?: string; role?: string }` | optional | ARIA accessibility attributes |
 
 
diff --git a/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md b/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
index 0f1f82ff9e..f1bcb7b70e 100644
--- a/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
+++ b/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
@@ -21,8 +21,8 @@ regenerate.
 | Measure | Value |
 |---|---|
 | Triaged directories | 5 |
-| Object sites in them | 455 |
-| Still-open (strip) sites | 196 |
+| Object sites in them | 456 |
+| Still-open (strip) sites | 197 |
 | Files carrying at least one | 30 |
 
 Remaining strip sites by class:
@@ -33,7 +33,7 @@ Remaining strip sites by class:
 | unresolved — needs a per-schema verdict | 33 |
 | wire / open — out of forced scope | 107 |
 | no door — no carrier, ADR-0049 territory | 14 |
-| no gate — carrier live, no parse | 29 |
+| no gate — carrier live, no parse | 30 |
 
 ## Posture, per triaged directory
 
@@ -43,12 +43,12 @@ The `strict` column is the one the campaign schedules against; it counts both th
 
 | Dir | Sites | strict | passthrough | catchall | strip |
 |---|---|---|---|---|---|
-| `ui/` | 171 | 116 | 5 | 0 | 50 |
+| `ui/` | 172 | 116 | 5 | 0 | 51 |
 | `data/` | 162 | 54 | 1 | 0 | 107 |
 | `automation/` | 75 | 49 | 0 | 0 | 26 |
 | `security/` | 20 | 7 | 0 | 0 | 13 |
 | `studio/` | 27 | 27 | 0 | 0 | 0 |
-| **total** | **455** | **253** | **6** | **0** | **196** |
+| **total** | **456** | **253** | **6** | **0** | **197** |
 
 ## File-level triage — site counts
 
@@ -65,7 +65,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `app.zod.ts` | 18 |
 | `bulk-action.zod.ts` | 3 |
 | `chart.zod.ts` | 8 |
-| `component.zod.ts` | 29 |
+| `component.zod.ts` | 30 |
 | `dashboard.zod.ts` | 11 |
 | `dataset.zod.ts` | 4 |
 | `i18n.zod.ts` | 6 |
@@ -76,7 +76,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `theme.zod.ts` | 6 |
 | `view.zod.ts` | 53 |
 | `widget.zod.ts` | 9 |
-| **total** | **171** |
+| **total** | **172** |
 
 ### `data/` — sites
 
@@ -156,18 +156,18 @@ over it is here.
 
 ### `ui/` — open
 
-**50 strip of 171**, in 7 file(s).
+**51 strip of 172**, in 7 file(s).
 
 | File | Strip | Sites |
 |---|---|---|
 | `action-params.zod.ts` | 1 | 1 |
 | `app.zod.ts` | 1 | 18 |
 | `chart.zod.ts` | 2 | 8 |
-| `component.zod.ts` | 29 | 29 |
+| `component.zod.ts` | 30 | 30 |
 | `i18n.zod.ts` | 5 | 6 |
 | `view.zod.ts` | 3 | 53 |
 | `widget.zod.ts` | 9 | 9 |
-| **total** | **50** | **171** |
+| **total** | **51** | **172** |
 
 | Bucket | Sites |
 |---|---|
@@ -175,7 +175,7 @@ over it is here.
 | unresolved — needs a per-schema verdict | 0 |
 | wire / open — out of forced scope | 3 |
 | no door — no carrier, ADR-0049 territory | 14 |
-| no gate — carrier live, no parse | 29 |
+| no gate — carrier live, no parse | 30 |
 
 ### `data/` — open
 
diff --git a/packages/lint/src/validate-page-field-bindings.test.ts b/packages/lint/src/validate-page-field-bindings.test.ts
index bd904d16c2..53f19ce8b0 100644
--- a/packages/lint/src/validate-page-field-bindings.test.ts
+++ b/packages/lint/src/validate-page-field-bindings.test.ts
@@ -84,8 +84,9 @@ describe('validatePageFieldBindings — highlights / KPI cards', () => {
 });
 
 describe('validatePageFieldBindings — record:details real authored shape', () => {
-  // Real pages author `sections: [{ label, fields }]`, which RecordDetailsProps
-  // does not describe (it survives because `properties` is unvalidated).
+  // Real pages author `sections: [{ label, fields }]` — the shape
+  // `RecordDetailsProps` now declares too (#5611; it used to declare an ID
+  // `string[]` that no page and no renderer ever used).
   it('walks sections[].fields[]', () => {
     const findings = validatePageFieldBindings({
       ...baseStack(),
diff --git a/packages/lint/src/validate-page-field-bindings.ts b/packages/lint/src/validate-page-field-bindings.ts
index d485073dd2..30d6e9e4fb 100644
--- a/packages/lint/src/validate-page-field-bindings.ts
+++ b/packages/lint/src/validate-page-field-bindings.ts
@@ -164,8 +164,11 @@ export interface ComponentFieldSpec {
 
 export const COMPONENT_FIELD_SPECS: Readonly<Record<string, ComponentFieldSpec>> = {
   'record:highlights': { props: ['fields'] },
-  // `sections`/`hideFields` are not in RecordDetailsProps, but every real page
-  // authors them (they survive because `properties` is unvalidated).
+  // `sections` (object form) and `hideFields` are what every real page authors,
+  // and since #5611 they are what `RecordDetailsProps` declares — this model and
+  // the spec agree. (Before that, `sections` was declared as an ID `string[]`
+  // and `hideFields` not at all; both survived only because `properties` is
+  // unvalidated.)
   'record:details': { props: ['fields', 'hideFields'], nestedSections: ['sections'] },
   'record:path': { props: ['statusField'] },
   'element:number': { props: ['field'] },
@@ -208,9 +211,11 @@ export function componentFieldRefs(
     const sections = Array.isArray(props[key]) ? (props[key] as unknown[]) : [];
     for (let si = 0; si < sections.length; si++) {
       const section = sections[si];
-      // A `sections` that is a plain `string[]` (the shape `RecordDetailsProps`
-      // actually declares — section IDs) yields nothing here, which is right:
-      // those are not field names.
+      // A non-object entry yields nothing here, which is right: lint runs on
+      // unvalidated `properties`, so it must survive off-spec input rather than
+      // throw on it. (Until #5611 the ID `string[]` this skips was the shape
+      // `RecordDetailsProps` declared; it declares the object form now, so this
+      // is a defensive guard rather than a divergence from the spec.)
       if (!isRec(section)) continue;
       refs.push(...fieldRefsFrom(section.fields, `${basePath}${sep}${key}[${si}].fields`));
     }
diff --git a/packages/spec/authorable-surface.json b/packages/spec/authorable-surface.json
index 98b3a4bca7..8118d6f372 100644
--- a/packages/spec/authorable-surface.json
+++ b/packages/spec/authorable-surface.json
@@ -7703,6 +7703,7 @@
     "ui/RecordDetailsProps:aria",
     "ui/RecordDetailsProps:columns",
     "ui/RecordDetailsProps:fields",
+    "ui/RecordDetailsProps:hideFields",
     "ui/RecordDetailsProps:layout",
     "ui/RecordDetailsProps:sections",
     "ui/RecordHighlightsProps:aria",
diff --git a/packages/spec/src/ui/component.test.ts b/packages/spec/src/ui/component.test.ts
index c172e0e8b8..c739bf8daf 100644
--- a/packages/spec/src/ui/component.test.ts
+++ b/packages/spec/src/ui/component.test.ts
@@ -149,14 +149,88 @@ describe('RecordDetailsProps', () => {
     expect(result.sections).toBeUndefined();
   });
 
-  it('should accept custom layout with sections', () => {
-    const details = { columns: '3' as const, layout: 'custom' as const, sections: ['sec-1', 'sec-2'] };
-    expect(() => RecordDetailsProps.parse(details)).not.toThrow();
-  });
-
   it('should reject invalid column value', () => {
     expect(() => RecordDetailsProps.parse({ columns: '5' })).toThrow();
   });
+
+  // #5611: `sections` is the OBJECT form — the only form any page authors and
+  // the only form any renderer reads. These fixtures are lifted verbatim from
+  // the real pages so the schema is pinned to authored reality, not to a shape
+  // invented here. Before this change every one of them was an `invalid_type`
+  // rejection at `sections[0]` (the old `z.array(z.string())`), and the whole
+  // `hideFields` key was silently stripped.
+  it('accepts the showcase section shape verbatim (project-detail.page.ts:49)', () => {
+    const details = {
+      layout: 'custom' as const,
+      sections: [
+        { label: 'Overview', columns: 2, fields: ['name', 'account', 'owner', 'status'] },
+        { label: 'Financials', columns: 2, fields: ['budget', 'spent'] },
+        { label: 'Timeline', columns: 2, fields: ['start_date', 'end_date'] },
+      ],
+    };
+    const result = RecordDetailsProps.parse(details);
+    expect(result.sections).toHaveLength(3);
+    expect(result.sections?.[0]).toEqual({
+      label: 'Overview',
+      columns: 2,
+      fields: ['name', 'account', 'owner', 'status'],
+    });
+    // `columns: 1` is authored too (task-detail.page.ts:76).
+    expect(() =>
+      RecordDetailsProps.parse({ sections: [{ label: 'Details', columns: 1, fields: ['notes'] }] }),
+    ).not.toThrow();
+  });
+
+  it('accepts a section with no columns (sys-user.page.ts:118)', () => {
+    const result = RecordDetailsProps.parse({
+      sections: [{ label: 'Identity', fields: ['name', 'image'] }],
+    });
+    expect(result.sections?.[0].columns).toBeUndefined();
+    expect(result.sections?.[0].fields).toEqual(['name', 'image']);
+  });
+
+  it('accepts an untitled section and a `name`-anchored one', () => {
+    // No label: the renderer draws it borderless. No name: it is untranslatable
+    // by construction, which is what `translation-section-name-missing` reports.
+    expect(() => RecordDetailsProps.parse({ sections: [{ fields: ['notes'] }] })).not.toThrow();
+    // `name` is the i18n anchor a lint rule tells authors to add, so the schema
+    // must accept it — the rule and the schema cannot disagree.
+    const named = RecordDetailsProps.parse({
+      sections: [{ name: 'identity', label: 'Identity', fields: ['name'] }],
+    });
+    expect(named.sections?.[0].name).toBe('identity');
+  });
+
+  it('requires `fields` on every section', () => {
+    const r = RecordDetailsProps.safeParse({ sections: [{ label: 'Empty' }] });
+    expect(r.success).toBe(false);
+    expect(r.success === false && r.error.issues[0].path).toEqual(['sections', 0, 'fields']);
+  });
+
+  it('rejects the retired ID-list form rather than silently half-reading it', () => {
+    const r = RecordDetailsProps.safeParse({ layout: 'custom', sections: ['overview'] });
+    expect(r.success).toBe(false);
+    expect(r.success === false && r.error.issues[0].code).toBe('invalid_type');
+    expect(r.success === false && r.error.issues[0].path).toEqual(['sections', 0]);
+  });
+
+  it('rejects an out-of-range section column count', () => {
+    expect(() =>
+      RecordDetailsProps.parse({ sections: [{ label: 'Wide', columns: 5, fields: ['a'] }] }),
+    ).toThrow();
+  });
+
+  it('preserves hideFields verbatim (sys-user.page.ts:106)', () => {
+    // Undeclared until #5611, so a non-strict `z.object` dropped it on the
+    // floor: the platform page's hidden-field list survived only because
+    // nothing ever parsed these props.
+    const hideFields = ['id', 'banned', 'ban_reason', 'ban_expires', 'email', 'role'];
+    const result = RecordDetailsProps.parse({
+      hideFields,
+      sections: [{ label: 'Audit', fields: ['created_at', 'updated_at'] }],
+    });
+    expect(result.hideFields).toEqual(hideFields);
+  });
 });
 
 describe('RecordRelatedListProps', () => {
diff --git a/packages/spec/src/ui/component.zod.ts b/packages/spec/src/ui/component.zod.ts
index e456af17c1..f2b7c80c54 100644
--- a/packages/spec/src/ui/component.zod.ts
+++ b/packages/spec/src/ui/component.zod.ts
@@ -76,10 +76,13 @@ import { FeedItemType, FeedFilterMode } from '../data/feed.zod';
 // gate, not to close schemas nobody calls — filed as #5068, which also
 // records the two constraints that stop it being a drive-by: `type` is an open
 // union (unregistered types like `record:line_items` are authored in the wild),
-// and real pages already author shapes these schemas do not declare
-// (`record:details` `sections[].fields[]` / `hideFields[]`, the record picker's
-// `labelField` — see `packages/lint/src/validate-page-field-bindings.ts`, which
-// has documented the untyped bag all along).
+// and real pages already author shapes these schemas do not declare (the record
+// picker's `labelField` — see `packages/lint/src/validate-page-field-bindings.ts`,
+// which has documented the untyped bag all along). `record:details`
+// `sections[]` / `hideFields[]` WAS the largest such divergence and is now
+// closed: #5611 re-declared `sections` in the object form every page actually
+// authors and declared `hideFields`, so wiring the gate no longer turns three
+// showcase pages and the `sys_user` platform page into hard parse errors.
 //
 // When #5068 lands, this file becomes `authorable` and the ratchet applies. The
 // verdict is pinned in `component.test.ts` and in the `ui/` tables of
@@ -157,8 +160,56 @@ export const PageCardProps = z.object({
 export const RecordDetailsProps = z.object({
   columns: z.enum(['1', '2', '3', '4']).default('2').describe('Number of columns for field layout (1-4)'),
   layout: z.enum(['auto', 'custom']).default('auto').describe('Layout mode: auto uses object highlightFields, custom uses explicit sections'),
-  sections: z.array(z.string()).optional().describe('Section IDs to show (required when layout is "custom")'),
+  /**
+   * Field groups rendered as the detail body, IN ORDER.
+   *
+   * Declared as the object form because that is the only form anything
+   * delivers or authors (#5611). Until 17.x this key was `z.array(z.string())`
+   * — "section IDs" — which no page in this repo, and no read path in
+   * `objectui`, has ever used: `RecordDetailsRenderer` maps every entry as an
+   * object (`s.name` / `s.label` / `s.fields`) with no string branch anywhere,
+   * `@object-ui/types`' `RecordDetailsComponentProps` mirror declares the
+   * object form, and the Studio block designer can only author
+   * `{label, columns, fields}`. The ID-list spelling was a declaration with no
+   * producer and no consumer, so it is gone rather than unioned in: one shape,
+   * not two de-facto contracts (Prime Directive #12).
+   */
+  sections: z.array(z.object({
+    /**
+     * Stable section identifier, snake_case. This is the i18n anchor: the
+     * heading resolves through `objects.<object>._sections.<name>.label`, so a
+     * section WITHOUT a name renders its authored `label` in every locale.
+     * `packages/lint`'s `translation-section-name-missing` rule exists to tell
+     * authors to add it, which is why it is declared here — a key one rule
+     * demands must not be a key the schema rejects.
+     */
+    name: z.string().optional().describe('Stable section identifier for i18n lookup (snake_case) — resolves `objects.<object>._sections.<name>.label`; a nameless section renders its authored label in every locale'),
+    /** Heading text. Omit for an untitled section, which renders borderless. */
+    label: I18nLabelSchema.optional().describe('Section heading (omit for an untitled, borderless section)'),
+    /**
+     * Field-grid width for THIS section; falls back to the renderer's own
+     * derivation when omitted.
+     *
+     * An int range rather than `z.union([z.literal(1), …])` — same accepted set
+     * (1-4), but the docs generator renders numeric literals as QUOTED strings
+     * (`'1' | '2'`, see `FormSectionSchema.columns` in `references/ui/view.mdx`),
+     * which would tell an author to write `columns: '2'` where this key requires
+     * `2`. Shipping a reference that misdocuments the key is the exact harm
+     * #5611 is fixing, so the shape that documents itself truthfully wins.
+     */
+    columns: z.number().int().min(1).max(4).optional().describe('Field-grid columns for this section (1-4). Omitted → the renderer derives the width.'),
+    /** Field names shown in this section, in order. */
+    fields: z.array(z.string()).describe('Field names rendered in this section, in order'),
+  })).optional().describe('Field groups rendered as the detail body, in order. Object form: `{ name?, label?, columns?, fields }`.'),
   fields: z.array(z.string()).optional().describe('Explicit field list to display (optional, overrides highlightFields)'),
+  /**
+   * Field names to omit from the body, applied to both `fields` and every
+   * section's `fields`. Authored by the published `sys_user` platform page and
+   * read by `RecordDetailsRenderer`; it was simply never declared, so the
+   * (unvalidated) props bag carried it. Declared now so the enforcement to come
+   * does not silently strip a live platform page's hidden-field list.
+   */
+  hideFields: z.array(z.string()).optional().describe('Field names to omit from the body — applied to `fields` and to every section\'s `fields` (used to dedupe fields already shown in `record:highlights` or as the page title)'),
   /** ARIA accessibility */
   aria: AriaPropsSchema.optional().describe('ARIA accessibility attributes'),
 });