@@ -0,0 +1,30 @@
+---
+'@objectstack/spec': minor
+'@objectstack/skills': patch
+'@object-ui/plugin-form': minor
+'@object-ui/types': minor
+'@object-ui/i18n': patch
+'@object-ui/console': patch
+---
+
+feat(spec,plugin-form)!: `ObjectForm` lays a form out and no longer picks its container; the `object-form` block drops `formType: 'split'` and `SplitForm` retires, while the block keeps opening `drawer` and `modal` forms itself
+
+Clause-②: no (narrowing)
+
+Metadata-protocol: narrowed (the `object-form` block's `formType` refuses `split`; its `splitDirection`, `splitSize`, `splitResizable` and `sections[].pane`, the `object-master-detail-form` block's `sections[].pane`, and `FormViewSchema.splitDirection`, are tombstones)
+
+<!-- adr-0087: not-required (already-registered form-view-presentation-types-removed, ui-form-view-type-layout-only) 18.3.0 is unreleased, so this change widens those two entries in place: the conversion now strips splitDirection and reaches object-form page blocks, four new RETIRED_KEYS_BY_MAJOR rows record the tombstoned keys, and the D3 entry names the block -->
+
+**BREAKING** accept-set narrowing on the `object-form` page block and the form view (`@objectstack/spec`), and a removed export (`@object-ui/plugin-form`). ADR-0050, the renderer half of #27155.
+
+The model: a form's `formType` says how it lays out its sections. Where it opens is the caller's. On the `object-form` block the caller is the block itself, so `drawer` and `modal` stay there as the two containers the block opens; `split` drew two panes and had no other reader, so it leaves with its renderer.
+
+- **FROM → TO (block).** `formType: 'split'` → `formType: 'tabbed'` (one tab per section) or delete the value for `simple`; delete each section's `pane` and the block's `splitDirection` / `splitSize` / `splitResizable`. To edit child records beside the parent, use an `object-master-detail-form` block. `formType: 'drawer'` and `formType: 'modal'` are unchanged. The `object-master-detail-form` block's parent `sections` share the shape, so delete each section's `pane` there too.
+- **FROM → TO (form view).** `splitDirection` on a form view → delete it. It joins `splitSize` and `splitResizable`, which left in the same release.
+- **The one-line fix.** Delete the retired value and keys. `os migrate meta --from 17` lists the edits for existing sources, and `--write` applies them. A stored page or view row is converted when it is read (the `form-view-presentation-types-removed` conversion now reaches `object-form` page blocks, the section `pane` of `object-master-detail-form` blocks, and `splitDirection` too), so a block saved with `split` keeps loading as a `simple` form.
+- **What the parse says.** `formType: 'split'` is refused by name with its prescription ("'split' was removed from the `object-form` `formType` enum in @objectstack/spec 18.3.0 (ADR-0050) — …"); each tombstoned key is refused on every `formType`. TypeScript rejects each at the authoring site.
+- **`@object-ui/plugin-form`.** `ObjectForm` renders the `simple`, `tabbed` and `wizard` layouts only; a `formType` of `drawer` or `modal` on a node handed straight to `<ObjectForm>` now renders the inline form, and the host opens its own drawer or dialog around it (the console's New and Edit dialogs already mount `ModalForm` themselves). The registered `object-form` block routes `drawer` and `modal` through the new internal `ObjectFormContainer`, which hands the node to `DrawerForm` or `ModalForm` as before. `SplitForm`, `SplitFormProps` and `SplitFormSchema` are no longer exported, and the block no longer publishes the `splitDirection`, `splitSize` and `splitResizable` inputs. FROM `import { SplitForm } from '@object-ui/plugin-form'` → TO a `TabbedForm`, or the `form` renderer's `fieldPanes` for a host that composes panes itself.
+- **`@object-ui/types`.** `ObjectFormSchema.formType` is `'simple' | 'tabbed' | 'wizard' | 'drawer' | 'modal'`, and its `splitDirection` / `splitSize` / `splitResizable` are the spec's tombstones by reference; the section `pane` member is gone.
+- **Console.** Studio's page-block inspector no longer offers `Split` for an `object-form` (its `engine.inspector.pageBlock.option.formType.split` string is removed from `@object-ui/i18n`), the record page passes no split keys, and a view whose `type` is not one of the three form layouts is no longer taken for a form (`@object-ui/console`).
+- **Supersedes one line of the form view `type` entry (#27155).** That entry says `splitDirection` stays declared; in this release it leaves too.
+- **Unchanged.** `drawerSide`, `drawerWidth`, `modalSize` and `modalCloseButton` keep their readers: the block's drawer and modal containers. The enforce-or-remove question for `drawerSide` / `drawerWidth` on form views stays on #27153.
@@ -74,13 +74,25 @@ its `schema`, but never a `dataSource` — that travels on
 one or wraps the component the same way.
 
 The components are on the package's export surface — `ObjectForm`,
-`TabbedForm`, `WizardForm`, `SplitForm`, `DrawerForm`, `ModalForm`,
-`EmbeddableForm`, `MasterDetailForm`, `LineItemsPanel`, `FormAnalytics`,
+`TabbedForm`, `WizardForm`, `DrawerForm`, `ModalForm`, `EmbeddableForm`, `MasterDetailForm`, `LineItemsPanel`, `FormAnalytics`,
 `FormSectionContainer` — alongside the layout helpers (`applyAutoLayout`,
 `inferColumns`, `filterCreateModeFields`, …) and the per-container schema types
 (`TabbedFormSchema`, `WizardFormSchema`, `ModalFormSchema`, …). There is no
 aggregate map among them.
 
+### Where an `object-form` block opens
+
+An `object-form`'s `formType` is the form's layout — `simple` (the default),
+`tabbed` or `wizard` — or, on the block, the container the block opens it in:
+`drawer` or `modal` (ADR-0050). `ObjectForm` only lays the form out; the block
+renderer is the caller that supplies the container, handing the node to
+`DrawerForm` (with `drawerSide` / `drawerWidth`) or `ModalForm` (with
+`modalSize` / `modalCloseButton`). A host that renders `<ObjectForm>` directly,
+or registers it under a key of its own as above, gets the inline form and opens
+its own drawer or dialog around it. The `split` form type and its `SplitForm`
+renderer were removed (ADR-0050): use `tabbed`, or an
+`object-master-detail-form` block to edit child records beside the parent.
+
 ## What an edit save writes
 
 Which fields an edit save sends, and which fields and line-item actions a caller is offered, is the same in the SDK and the Console. It is documented under [What an edit save writes](/docs/ui/forms#what-an-edit-save-writes).
@@ -103,7 +115,7 @@ The plugin supports these field types:
 `@object-ui/types` alongside the rest of the JSON contract. This package imports
 them and does not re-export them — the form types on its own entry are the
 per-container ones (`TabbedFormSchema`, `WizardFormSchema`, `ModalFormSchema`,
-`SplitFormSchema`, `DrawerFormSchema`, `MasterDetailFormSchema`).
+`DrawerFormSchema`, `MasterDetailFormSchema`).
 
 ```typescript
 import type { FormSchema, FormField } from '@object-ui/types';
 
@@ -1906,12 +1906,12 @@ The published metadata item body, opaque by ruling (1C). Shape is the item's own
 | **tabPosition** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Tab strip position (tabbed forms) |
 | **allowSkip** | `boolean` | optional | Wizard step-gate opt-out: allow entering a later step without submitting the one before it. Navigation freedom, NOT a validation exemption — the final submit still re-validates every step and returns to the first failing one. Default (absent/false): steps unlock in array order as each prior step submits validly. UI admission only, never authorization. |
 | **showStepIndicator** | `boolean` | optional | Show the wizard step indicator (renderer default: shown). Step progress (completed/current/upcoming/invalid) is derived from the step gate — this boolean is the only authorable progress surface. |
-| **splitDirection** | `Enum<'horizontal' \| 'vertical'>` | optional | Split orientation (split forms) |
+| **splitDirection** | `never` | optional | [REMOVED] `view.form.splitDirection` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it set the pane orientation of a split form, and the split form renderer retired in the same release, so no form draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
 | **splitSize** | `never` | optional | [REMOVED] `view.form.splitSize` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it sized the primary pane of a `type: 'split'` form, and `split` left the form view `type` in the same release, so no form view draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
 | **splitResizable** | `never` | optional | [REMOVED] `view.form.splitResizable` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it made the panes of a `type: 'split'` form resizable, and `split` left the form view `type` in the same release, so no form view draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
-| **drawerSide** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Drawer side (drawer forms) |
-| **drawerWidth** | `string` | optional | [DEPRECATED → size buckets] Drawer width, e.g. "480px". A pixel width cannot be chosen without knowing the client viewport — the renderer derives it. |
-| **modalSize** | `Enum<'sm' \| 'default' \| 'lg' \| 'xl' \| 'full'>` | optional | Modal size (modal forms) |
+| **drawerSide** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Edge the drawer container opens from, when the React `ObjectForm` block opens this form with formType 'drawer' |
+| **drawerWidth** | `string` | optional | [DEPRECATED → size buckets] Width of the drawer container the React `ObjectForm` block opens with formType 'drawer', e.g. "480px". A pixel width cannot be chosen without knowing the client viewport — the renderer derives it. |
+| **modalSize** | `Enum<'sm' \| 'default' \| 'lg' \| 'xl' \| 'full'>` | optional | Size bucket of the dialog a caller opens this form in: the console's New / Edit dialog, or the modal container of the React `ObjectForm` block (formType 'modal') |
 | **data** | `{ provider: 'object'; object: string } \| { provider: 'value'; items: any[] } \| { provider: 'schema'; schemaId: string; schema?: Record<string, any> }` | optional | Data source configuration (defaults to "object" provider) |
 | **sections** | `{ name?: string; label?: string \| Record<string, string>; description?: string; collapsible?: boolean; … }[]` | optional |  |
 | **groups** | `{ name?: string; label?: string \| Record<string, string>; description?: string; collapsible?: boolean; … }[]` | optional | [LEGACY ALIAS → `sections`] Accepted for back-compat and folded onto `sections` at parse; `sections` wins when both are present. Prefer `sections`. |
@@ -1985,12 +1985,12 @@ The published metadata item body, opaque by ruling (1C). Shape is the item's own
 | **tabPosition** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Tab strip position (tabbed forms) |
 | **allowSkip** | `boolean` | optional | Wizard step-gate opt-out: allow entering a later step without submitting the one before it. Navigation freedom, NOT a validation exemption — the final submit still re-validates every step and returns to the first failing one. Default (absent/false): steps unlock in array order as each prior step submits validly. UI admission only, never authorization. |
 | **showStepIndicator** | `boolean` | optional | Show the wizard step indicator (renderer default: shown). Step progress (completed/current/upcoming/invalid) is derived from the step gate — this boolean is the only authorable progress surface. |
-| **splitDirection** | `Enum<'horizontal' \| 'vertical'>` | optional | Split orientation (split forms) |
+| **splitDirection** | `never` | optional | [REMOVED] `view.form.splitDirection` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it set the pane orientation of a split form, and the split form renderer retired in the same release, so no form draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
 | **splitSize** | `never` | optional | [REMOVED] `view.form.splitSize` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it sized the primary pane of a `type: 'split'` form, and `split` left the form view `type` in the same release, so no form view draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
 | **splitResizable** | `never` | optional | [REMOVED] `view.form.splitResizable` was removed in @objectstack/spec 18.3.0 (ADR-0050) — it made the panes of a `type: 'split'` form resizable, and `split` left the form view `type` in the same release, so no form view draws panes. Delete the key. Run `os migrate meta --from 17` to list the mechanical edits for existing sources; `--write` applies the ones it can prove, and you apply the rest by hand. |
-| **drawerSide** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Drawer side (drawer forms) |
-| **drawerWidth** | `string` | optional | [DEPRECATED → size buckets] Drawer width, e.g. "480px". A pixel width cannot be chosen without knowing the client viewport — the renderer derives it. |
-| **modalSize** | `Enum<'sm' \| 'default' \| 'lg' \| 'xl' \| 'full'>` | optional | Modal size (modal forms) |
+| **drawerSide** | `Enum<'top' \| 'bottom' \| 'left' \| 'right'>` | optional | Edge the drawer container opens from, when the React `ObjectForm` block opens this form with formType 'drawer' |
+| **drawerWidth** | `string` | optional | [DEPRECATED → size buckets] Width of the drawer container the React `ObjectForm` block opens with formType 'drawer', e.g. "480px". A pixel width cannot be chosen without knowing the client viewport — the renderer derives it. |
+| **modalSize** | `Enum<'sm' \| 'default' \| 'lg' \| 'xl' \| 'full'>` | optional | Size bucket of the dialog a caller opens this form in: the console's New / Edit dialog, or the modal container of the React `ObjectForm` block (formType 'modal') |
 | **data** | `{ provider: 'object'; object: string } \| { provider: 'value'; items: any[] } \| { provider: 'schema'; schemaId: string; schema?: Record<string, any> }` | optional | Data source configuration (defaults to "object" provider) |
 | **sections** | `{ name?: string; label?: string \| Record<string, string>; description?: string; collapsible?: boolean; … }[]` | optional |  |
 | **groups** | `{ name?: string; label?: string \| Record<string, string>; description?: string; collapsible?: boolean; … }[]` | optional | [LEGACY ALIAS → `sections`] Accepted for back-compat and folded onto `sections` at parse; `sections` wins when both are present. Prefer `sections`. |