@@ -34,6 +34,11 @@ import {
   RowHeightSchema,
   RowColorConfigSchema,
   ListViewSchema,
+  // [#21464] `object-form.submitBehavior` is the form view's own member (read
+  // off `FormViewSchema.shape`, the one place that declares the post-submit
+  // union): both form renderers switch on exactly that union, so one
+  // declaration judges the form view and the block.
+  FormViewSchema,
 } from './view.zod';
 // [#21445] `object-grid.bulkActionDefs` is the list view's bulk-action def,
 // by identity — the element `ListViewSchema.bulkActionDefs` declares.
@@ -5283,6 +5288,44 @@ const OBJECT_FORM_LAYOUT_RETIRED: ReadonlyMap<string, string> = new Map([
     + 'Run `os migrate meta --from 17` to list the mechanical edits for existing sources; apply them by hand.'],
 ]);
 
+/**
+ * [#21464] An `object-form`'s `mobile` block — the five members the form reads
+ * at the `.objectui-sha` pin `89cad75d55` (`plugin-form/src/ObjectForm.tsx:1857-1942`,
+ * the flat arm only), and nothing else. No form view declares the block, so
+ * the shape is the read's own, as objectui declares it (`ObjectFormSchema.mobile`):
+ *
+ * - `stickyActions` pins the submit / cancel bar to the bottom of the viewport
+ *   (`:1935`, `:1941`);
+ * - `stepper` routes a flat form through the wizard: `true` always (a desktop
+ *   viewport included), `'auto'` only on a phone-width viewport once the form
+ *   has `stepperMinFields` fields (`:1874-1884`, default 8);
+ *   `stepperFieldsPerStep` is the fields per step (`:1876`, default 1 — the
+ *   read clamps a smaller count to 1);
+ * - `fullscreenLongText` offers the fullscreen editor on every long-text field
+ *   (`:1858-1869`).
+ *
+ * The block's presence marks the wrapper (`data-mobile-form`, `:1942`), so an
+ * empty `{}` is legal and changes nothing else. Module-private, as
+ * {@link ObjectKanbanLaneSchema} is.
+ */
+const ObjectFormMobileSchema = lazySchema(() => strictObject({
+  surface: 'this `object-form` `mobile` block',
+  history:
+    'Until this shape was declared, `mobile` was `z.unknown()`: a misspelled member or a `stepper` '
+    + 'value outside `true` / `false` / `\'auto\'` passed, and the form rendered without it.',
+}, {
+  stickyActions: z.boolean().optional()
+    .describe('Pin the submit / cancel bar to the bottom of a phone-width viewport'),
+  stepper: z.union([z.boolean(), z.literal('auto')]).optional()
+    .describe("One-step-at-a-time wizard for a flat form — `true` always, `'auto'` only on a phone-width viewport once the form has `stepperMinFields` fields, `false` (the default) never"),
+  stepperMinFields: z.number().int().positive().optional()
+    .describe("The field count at which `stepper: 'auto'` steps up (default 8)"),
+  stepperFieldsPerStep: z.number().int().positive().optional()
+    .describe('Fields shown per stepper step (default 1)'),
+  fullscreenLongText: z.boolean().optional()
+    .describe('Offer a fullscreen editor on textarea and rich-text fields'),
+}));
+
 /**
  * `object-form` (objectui `plugin-form/src/ObjectForm.tsx` @ `eb7f586b`, plus
  * the sub-forms it forwards the whole bag into: `TabbedForm`, `WizardForm`,
@@ -5318,8 +5361,36 @@ export const ObjectFormPropsSchema = lazySchema(() => strictObject({
   }).optional()
     .describe("Field layout — 'vertical' (the renderer default) or 'horizontal'. Multi-column is not a layout value: set `columns`"),
   columns: z.number().optional().describe('Number of field columns (multi-column forms), honoured under either `layout`'),
+  /**
+   * [#21464] HELD at `z.unknown()` entries, in the enumeration pin's ledger as
+   * held for a ruling. The renderer's own declared type is field-name strings
+   * (objectui `ObjectFormSchema.fields: string[]`), but its read also draws a
+   * `{ name }` entry by that name (`plugin-form/src/ObjectForm.tsx:961-981`,
+   * `flatFields.ts:71-79` at the pin `89cad75d55`), and measured writers author
+   * one — objectui's published page-builder guide among them — so typing the
+   * member to strings would refuse a value the form draws.
+   */
   fields: z.array(z.unknown()).optional().describe('Limit/order the fields shown'),
+  /**
+   * [#21464] Kept `z.unknown()`, in the enumeration pin's ledger with the
+   * objectui-held contracts: each member is objectui's runtime form field
+   * (`FormField`, identity key `name`), drawn whole by the form renderer
+   * (`plugin-form/src/customFieldsMerge.ts:78-108` at the pin `89cad75d55`).
+   * The spec declares no such field — its own form field (`FormFieldSchema`,
+   * `view.zod.ts`) is keyed by `field` and is never matched by the merge — so
+   * the spec declares that contract first, then this member takes it.
+   */
   customFields: z.unknown().optional().describe('Custom field definitions merged into the generated set'),
+  /**
+   * [#21464] HELD at `z.unknown()` entries, in the enumeration pin's ledger as
+   * held for a ruling. The form view's own `sections` (`FormSectionSchema`) is
+   * the by-reference shape, and every section key the renderer reads is
+   * declared there, but a section's `fields` also draws an inline runtime form
+   * field `{ name, type, … }` as it stands (`plugin-form/src/sectionFields.ts:367-369`
+   * at the pin `89cad75d55`, its "shape 3"), which the form view's field entry
+   * (keyed by `field`) refuses; objectui's README and its own pins author that
+   * shape and assert that it renders and submits.
+   */
   sections: z.array(z.unknown()).optional()
     .describe('Form sections ({ label, description?, fields } — wizard steps / tab panes)'),
   title: I18nLabelSchema.optional().describe('Form title'),
@@ -5335,7 +5406,15 @@ export const ObjectFormPropsSchema = lazySchema(() => strictObject({
   drawerWidth: z.union([z.string(), z.number()]).optional().describe('Drawer width (drawer)'),
   modalSize: z.enum(['sm', 'default', 'lg', 'xl', 'full']).optional().describe('Modal size (modal)'),
   modalCloseButton: z.boolean().optional().describe('Show the modal close button (modal)'),
-  contentLayout: z.unknown().optional().describe('Modal content layout config (modal)'),
+  /**
+   * [#21464] Typed to the read: the modal presentation is its only reader,
+   * and it tests `schema.contentLayout === 'tabbed' && groups.length > 1`
+   * (`plugin-form/src/ModalForm.tsx:854` at the pin `89cad75d55`, declared
+   * `'simple' | 'tabbed'` at `:151`); any other value stacks the sections, so
+   * a misspelled `'tabs'` used to draw the stacked layout with no report.
+   */
+  contentLayout: z.enum(['simple', 'tabbed']).optional()
+    .describe("How the modal presentation lays out its sections (modal) — 'simple' stacks them (the default); 'tabbed' puts each section on its own tab once more than one section has a field to show"),
   confirmOnDiscard: z.boolean().optional().describe('Confirm before discarding edits (drawer/modal)'),
   submitText: I18nLabelSchema.optional().describe('Submit button label'),
   cancelText: I18nLabelSchema.optional().describe('Cancel button label'),
@@ -5344,15 +5423,42 @@ export const ObjectFormPropsSchema = lazySchema(() => strictObject({
   showSubmit: z.boolean().optional().describe('Show the submit button'),
   showCancel: z.boolean().optional().describe('Show the cancel button'),
   showReset: z.boolean().optional().describe('Show the reset button'),
-  submitBehavior: z.unknown().optional()
-    .describe("What happens after a successful submit ({ kind: 'thank-you' | …, title?, message? })"),
+  /**
+   * [#21464] The form view's own `submitBehavior` member, by reference
+   * (`FormViewSchema.shape.submitBehavior`, the union discriminated on
+   * `kind`). Both form renderers switch on `kind` and read exactly that
+   * union's members — `url` and `delayMs` on `redirect`, `title` and `message`
+   * on `thank-you` (`plugin-form/src/ObjectForm.tsx:1312-1370` and
+   * `WizardForm.tsx:1005-1065` at the pin `89cad75d55`) — and judge a redirect
+   * `url` at submit by parsing a form view through this same schema
+   * (`submitRedirect.ts:202`), so one declaration judges the form view, this
+   * block and the renderer's own verdict. A `kind` outside the four fell
+   * through to the thank-you arm in silence.
+   */
+  submitBehavior: FormViewSchema.shape.submitBehavior
+    .describe("What happens after a successful submit — the same block a form view's `submitBehavior` declares: `{ kind: 'thank-you', title?, message? }`, `{ kind: 'redirect', url, delayMs? }` (a relative `url`, interpolating declared record fields as `{{record.field_name}}`), `{ kind: 'continue' }` or `{ kind: 'next-record' }`. Takes precedence over `navigateOnSuccess` and `resetOnSuccess`"),
   successMessage: I18nLabelSchema.optional().describe('Toast message on successful submit'),
   resetOnSuccess: z.boolean().optional().describe('Reset the form after a successful submit'),
-  navigateOnSuccess: z.unknown().optional().describe('Navigate after a successful submit'),
+  /**
+   * [#21464] Typed to the read: `resolveSuccessNavigate`
+   * (`plugin-form/src/successBehavior.ts:118-131` at the pin `89cad75d55`,
+   * called from `ObjectForm.tsx:1373` and `WizardForm.tsx:1071`) takes a
+   * string template, replaces `{id}` / `{recordId}` with the saved record's
+   * id (URL-escaped) and follows the result only when it is a relative
+   * reference; a declared value it refuses is reported on the success toast
+   * (`ObjectForm.tsx:1412-1429`). Any other value reached `template.replace`
+   * after the record had been written, and the submit then reported a failure.
+   * It is read only when `submitBehavior` is absent, and the renderer marks it
+   * deprecated in that key's favour.
+   */
+  navigateOnSuccess: z.string().optional()
+    .describe("Relative path to navigate to after a successful create/update — `{id}` / `{recordId}` are replaced with the saved record's id, URL-escaped; an absolute URL is refused at submit and reported on the success toast. Ignored when `submitBehavior` is set — prefer `submitBehavior`"),
   readOnly: z.boolean().optional().describe('Render every field read-only'),
   initialValues: z.record(z.string(), z.unknown()).optional().describe('Prefill values (create mode)'),
   initialData: z.record(z.string(), z.unknown()).optional().describe('Alternate spelling of `initialValues` the renderer also reads'),
-  mobile: z.unknown().optional().describe('Mobile presentation overrides'),
+  /** [#21464] The five members the form reads — see {@link ObjectFormMobileSchema}. */
+  mobile: ObjectFormMobileSchema.optional()
+    .describe('Phone presentation options, each opt-in — `{ stickyActions?, stepper?, stepperMinFields?, stepperFieldsPerStep?, fullscreenLongText? }`. Read by the flat (simple, sectionless) form'),
 }));
 /** Author state (ADR-0122: the bare name is the author state). */
 export type ObjectFormProps = z.input<typeof ObjectFormPropsSchema>;
@@ -5503,6 +5609,13 @@ export const ObjectMasterDetailFormPropsSchema = lazySchema(() => strictObject({
     error: (issue) =>
       typeof issue.input === 'string' ? MASTER_DETAIL_FORM_TYPE_RETIRED.get(issue.input) : undefined,
   }).optional().describe("Parent form presentation — the two variants the renderer honours for the parent half"),
+  /**
+   * [#21464] `sections` and `fields` are handed to the parent `object-form`
+   * verbatim (`plugin-form/src/MasterDetailForm.tsx:1692-1693` at the pin
+   * `89cad75d55`), so each is read exactly as that block's member is — and is
+   * HELD with it, in the enumeration pin's ledger, for the same reason (see
+   * {@link ObjectFormPropsSchema}'s `sections` and `fields`).
+   */
   sections: z.array(z.unknown()).optional().describe('Parent form sections'),
   fields: z.array(z.unknown()).optional().describe('Parent fields shown'),
   details: z.array(masterDetailDetailEntry()).optional()