@@ -0,0 +1,40 @@
+---
+'@objectstack/spec': minor
+'@objectstack/lint': patch
+---
+
+feat(spec)!: an `object-master-detail-form` block's detail entries are a strict shape, and their columns are the inline grid column contract (#20928)
+
+Clause-②: yes (narrowing)
+
+<!-- adr-0087: registered ui-object-master-detail-form-details-closed -->
+
+**BREAKING** — an accept-set narrowing on a published authoring surface, shipped as `minor` under the repo's launch-window convention for accept-set narrowings. The console's master-detail grid reads one column shape from three carriers: a relationship field's `inlineColumns`, a form view's `subforms[].columns`, and an `object-master-detail-form` page block's `details[].columns`. The first two were judged; the third was `z.array(z.unknown())`.
+
+**`@objectstack/spec`**
+
+- **`ComponentPropsMap['object-master-detail-form'].details`** is now an array of strict detail entries: `childObject` (required), `relationshipField`, `columns`, `formFields`, `inlineMode` (`grid` | `form`), `amountField`, `sortField`, `totalField`, `title`, `minRows`, `maxRows` and `addLabel` — the keys the console's `MasterDetailForm` reads off an entry. An unknown key is named, with a rename for the near-misses a form view's `subforms[]` entry also answers (`foreignKey` → `relationshipField`, `object` → `childObject`, …).
+- **`details[].columns`** references `InlineGridColumnSchema`, the strict, name-keyed column the other two carriers take. Every rule the column schema holds applies here too, with its own message: an unknown key is named; the retired `field` spelling (and `fieldName`, `key`) is refused with the prescription naming `name`; a column without `name` is refused; `scale` on a column declaring `type: 'currency'` is refused with the currency ruling's remedy. Page-component `properties` is read by the component-props gate, so `objectstack validate`, `build` and `lint` report these as advisory `component-props-unknown-key` / `component-props-invalid` findings; a stored page still saves and loads, because `properties` is not parsed on the metadata save or load path.
+- **`defineStack`'s cross-reference check** now reaches the block wherever a page carries it (a region, a container's children, a slot) and judges a detail column that declares no `type` as the type it renders, as it already does on the other two carriers: an identity-only column over a `currency` field of the entry's `childObject` that carries `scale` is refused with the column schema's own message (`STACK_CROSS_REFERENCE_INVALID`, 422). A child object the stack does not declare, a column naming no field of it, and a column the column schema refuses on its own (left to the component-props gate) are not judged there.
+- **New type `ObjectMasterDetailFormPropsParsed`** — the post-parse shape of `ObjectMasterDetailFormProps`. The two now differ, because a column's `readonlyWhen` / `requiredWhen` bare-string predicate normalizes to an Expression envelope at parse.
+
+**`@objectstack/lint`**
+
+- **`field-no-consumers`** reads an `object-master-detail-form` detail entry as the child collection it is: a column `name`, `amountField` and `relationshipField` credit the field of the entry's `childObject`, `totalField` the parent's, and an entry with no `columns` credits the columns the child derives. A child field drawn only by a master-detail block's grid was reported inert.
+
+## FROM → TO
+
+| you wrote | write instead |
+|:--|:--|
+| `details: [{ title: 'Lines' }]` | `details: [{ title: 'Lines', childObject: 'invoice_line' }]` |
+| `details: [{ childObject: 'invoice_line', columns: ['product', 'quantity'] }]` | `details: [{ childObject: 'invoice_line', columns: [{ name: 'product' }, { name: 'quantity' }] }]` |
+| `details: [{ childObject: 'invoice_line', columns: [{ field: 'quantity' }] }]` | `details: [{ childObject: 'invoice_line', columns: [{ name: 'quantity' }] }]` |
+| `details: [{ childObject: 'invoice_line', columns: [{ name: 'amount', type: 'currency', scale: 2 }] }]` | `details: [{ childObject: 'invoice_line', columns: [{ name: 'amount', type: 'currency' }] }]` |
+| `columns: [{ name: 'amount', scale: 2 }]` where `amount` is a `currency` field of the entry's `childObject` | `columns: [{ name: 'amount' }]` |
+| a detail entry or column carrying a key its shape does not declare | the entry or column without that key |
+
+The one-line fix: give every detail entry its `childObject`, write each column as `{ name, … }` using only the keys a relationship field's `inlineColumns` accepts, and delete `scale` from any column that renders as a currency column, whether it declares `type: 'currency'` or takes it from a `currency` child field. Nothing replaces `scale` there: the currency's ISO 4217 minor unit decides the displayed decimals.
+
+## Who is affected, measured
+
+On `origin/main` `ebdb6f2aca`: one authored `object-master-detail-form` block in the examples (the showcase project workspace, one entry `{ title, childObject, addLabel }`, no columns), which parses unchanged, and one documentation example whose three bare-string columns are rewritten as `{ name }` columns in this change. Zero `field`-keyed detail columns. Deployed metadata was not measured.
@@ -765,7 +765,10 @@ properties:
 
 A parent record edited alongside its child collections is the declared
 `object-master-detail-form` block. `details` entries derive the foreign key and
-columns from the child object's metadata when you omit them.
+columns from the child object's metadata when you omit them. An authored
+`columns` list takes the same name-keyed column a relationship field's
+`inlineColumns` takes: `{ name }` alone fills the label and cell type from the
+child field.
 
 {/* os:check-yaml PageComponentSchema */}
 ```yaml
@@ -779,7 +782,10 @@ properties:
     - title: Line Items
       childObject: invoice_line
       relationshipField: invoice_id
-      columns: [product, quantity, unit_price]
+      columns:
+        - name: product
+        - name: quantity
+        - name: unit_price
 ```
 
 For the *master/detail browsing* pattern — pick a record on the left, show it on
 
@@ -950,7 +950,7 @@ Sort field and direction pair
 | **formType** | `Enum<'simple' \| 'tabbed'>` | optional | Parent form presentation — the two variants the renderer honours for the parent half |
 | **sections** | `any[]` | optional | Parent form sections |
 | **fields** | `any[]` | optional | Parent fields shown |
-| **details** | `any[]` | optional | Detail collections (`{ title, childObject, addLabel?, columns?, relationshipField? }` — FK and columns auto-derive from child metadata) |
+| **details** | `{ childObject: string; relationshipField?: string; columns?: object[]; formFields?: string[]; … }[]` | optional | Detail collections — each a strict entry (`{ childObject, title?, addLabel?, columns?, relationshipField?, … }`) whose `columns` are the inline grid columns a relationship field's `inlineColumns` takes; the FK and columns auto-derive from child metadata when omitted |
 | **title** | `string \| Record<string, string>` | optional | Form title |
 | **submitText** | `string \| Record<string, string>` | optional | Submit button label |
 | **cancelText** | `string \| Record<string, string>` | optional | Cancel button label |
@@ -959,6 +959,23 @@ Sort field and direction pair
 | **initialData** | `Record<string, any>` | optional | Alternate spelling of `initialValues` the renderer also reads |
 | **taxRateField** | `string` | optional | Child field holding the per-line tax rate (line-items totals) |
 
+### Nested Shape: `ObjectMasterDetailFormProps.details[number]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **childObject** | `string` | ✅ | Child object whose records are entered inline |
+| **relationshipField** | `string` | optional | FK on the child pointing back to the parent (auto-detected from the child's master_detail/lookup field when omitted) |
+| **columns** | `{ name: string; label?: string; type?: Enum<'text' \| 'number' \| 'currency' \| 'date' \| 'datetime' \| 'time' \| 'select' \| 'lookup' \| 'file'>; width?: number; … }[]` | optional | Editable grid columns (derived from the child object when omitted). Each entry is the strict, name-keyed inline grid column a relationship field's `inlineColumns` takes (`{ name, label?, type?, … }` — objectui GridColumn); identity-only entries (`{ name }`) hydrate everything else from the child object's fields. Unknown keys and the retired `field` spelling are refused at parse. |
+| **formFields** | `string[]` | optional | Child field names for the per-row expand form (derived from the child object's editable fields when omitted) |
+| **inlineMode** | `Enum<'grid' \| 'form'>` | optional | Inline-edit form factor: 'grid' = editable cells; 'form' = read-only list + per-row full form. Resolved from the relationship field's `inlineEdit` when omitted |
+| **amountField** | `string` | optional | Numeric child column summed for the running total |
+| **sortField** | `string` | optional | Child field holding the line sort position, stamped on drag-reorder (derived from a `position` / `sort_order` / … field when omitted) |
+| **totalField** | `string` | optional | Parent field to receive the rolled-up sum |
+| **title** | `string` | optional | Section title |
+| **minRows** | `number` | optional | Minimum number of rows |
+| **maxRows** | `number` | optional | Maximum number of rows |
+| **addLabel** | `string` | optional | Add-row button label |
+
 
 ---
 
 
@@ -21,7 +21,7 @@ The `strict` column is the one the campaign schedules against; it counts both th
 
 | Dir | Sites | strict | passthrough | catchall | strip |
 |---|---|---|---|---|---|
-| `ui/` | 188 | 178 | 3 | 0 | 7 |
+| `ui/` | 189 | 179 | 3 | 0 | 7 |
 
 ## `ui/` — sites
 
@@ -36,7 +36,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `app.zod.ts` | 19 |
 | `bulk-action.zod.ts` | 4 |
 | `chart.zod.ts` | 8 |
-| `component.zod.ts` | 56 |
+| `component.zod.ts` | 57 |
 | `dashboard.zod.ts` | 11 |
 | `dataset.zod.ts` | 4 |
 | `i18n.zod.ts` | 1 |
@@ -46,23 +46,23 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `sharing.zod.ts` | 1 |
 | `view.zod.ts` | 62 |
 | `widget.zod.ts` | 1 |
-| **total** | **188** |
+| **total** | **189** |
 
 ## `ui/` — open
 
 Per file, how many of its sites still silently discard unknown keys. The `Class`
 column that decides the bucket split is hand-written in the ledger; the arithmetic
 over it is here.
 
-**7 strip of 188**, in 4 file(s).
+**7 strip of 189**, in 4 file(s).
 
 | File | Strip | Sites |
 |---|---|---|
 | `action-params.zod.ts` | 1 | 1 |
 | `app.zod.ts` | 1 | 19 |
 | `view.zod.ts` | 4 | 62 |
 | `widget.zod.ts` | 1 | 1 |
-| **total** | **7** | **188** |
+| **total** | **7** | **189** |
 
 | Bucket | Sites |
 |---|---|
 
@@ -835,3 +835,92 @@ describe('[#20951] validateFieldConsumers — a child collection credits its chi
     });
   });
 });
+
+/**
+ * [#20928] The third carrier of an inline grid: an `object-master-detail-form`
+ * page block's `details` entries. Each entry names its child in `childObject`
+ * and its grid in `columns`, exactly as a `subforms` entry does, so it is read
+ * as a child collection: a column `name` and `amountField` /
+ * `relationshipField` against the child, `totalField` against the parent the
+ * block's `objectName` binds, and an entry with no `columns` credits the grid
+ * the child derives.
+ *
+ * `inv` is the parent and `line` the child; each declares a field the other's
+ * key names, so a key read against the wrong object shows up as the wrong one
+ * of the pair going quiet. `memo` is named nowhere: the control.
+ */
+describe('[#20928] validateFieldConsumers — an `object-master-detail-form` detail entry is a child collection', () => {
+  const data = { provider: 'object', object: 'inv' };
+
+  const stack = (details: unknown[], slots?: AnyRec): AnyRec => ({
+    objects: [
+      { name: 'inv', fields: { name: { type: 'text' }, qty: { type: 'number' }, total: { type: 'number' } } },
+      {
+        name: 'line',
+        fields: {
+          name: { type: 'text' },
+          invoice: { type: 'master_detail', reference: 'inv' },
+          qty: { type: 'number' },
+          total: { type: 'number' },
+          line_total: { type: 'number' },
+          memo: { type: 'text' },
+        },
+      },
+    ],
+    views: [{ list: { type: 'grid', data, columns: [{ field: 'name' }] } }],
+    pages: [{
+      name: 'inv_entry',
+      regions: [{
+        name: 'main',
+        components: [{ type: 'object-master-detail-form', properties: { objectName: 'inv', details } }],
+      }],
+      ...(slots ? { kind: 'slotted', slots } : {}),
+    }],
+  });
+
+  /** `object.field` → verdict, for every field the rule reports. */
+  const verdicts = (s: AnyRec): Record<string, string> =>
+    Object.fromEntries(validateFieldConsumers(s).map((f) => [`${f.object}.${f.field}`, f.verdict]));
+
+  /** Every non-name field of both objects, reported: what a block with no detail entry leaves. */
+  const NOTHING_READ = {
+    'inv.qty': 'inert',
+    'inv.total': 'inert',
+    'line.qty': 'inert',
+    'line.total': 'inert',
+    'line.line_total': 'inert',
+    'line.memo': 'inert',
+  };
+
+  it('baseline: a block with no detail entry reads no field of either object', () => {
+    expect(verdicts(stack([]))).toEqual(NOTHING_READ);
+  });
+
+  it("an authored column credits the CHILD's field, not the parent's same-named one", () => {
+    const { 'line.qty': _credited, ...rest } = NOTHING_READ;
+    expect(verdicts(stack([{ childObject: 'line', columns: [{ name: 'qty' }] }]))).toEqual(rest);
+  });
+
+  it("`amountField` credits the CHILD's field and `totalField` the PARENT's — each same-named counterpart stays reported", () => {
+    const entry = { childObject: 'line', columns: [{ name: 'qty' }], amountField: 'line_total', totalField: 'total' };
+    expect(verdicts(stack([entry]))).toEqual({
+      'inv.qty': 'inert',
+      'line.total': 'inert',
+      'line.memo': 'inert',
+    });
+  });
+
+  it('an entry with no `columns` credits the columns its child derives', () => {
+    // `deriveInlineGridColumns` draws every editable child field but the
+    // relationship back to the parent, so only the parent's two stay reported.
+    expect(verdicts(stack([{ childObject: 'line' }]))).toEqual({ 'inv.qty': 'inert', 'inv.total': 'inert' });
+  });
+
+  it("control: the page slot map's own `details` key holds components, and one read as an entry is read exactly as anywhere else", () => {
+    const component = { type: 'record:details', properties: { objectName: 'line', fields: ['memo'] } };
+    const elsewhere = verdicts(stack([], { header: [component] }));
+    // Non-vacuity: the component does read a field, so a slot that skipped it would show.
+    expect(elsewhere['line.memo']).toBeUndefined();
+    expect(verdicts(stack([], { details: [component] }))).toEqual(elsewhere);
+  });
+});
@@ -283,11 +283,19 @@ const WRITE_KEYS: ReadonlySet<string> = new Set([
 /**
  * [#20929] Keys whose array entries are INLINE CHILD COLLECTIONS: each entry
  * names its child object in `childObject` and the child's grid in `columns`.
- * Today that is a form view's `subforms` (`FormViewSchema.subforms`, on a view
- * container's `form` and on every `formViews` entry), whose `columns` is the
- * same `InlineGridColumnSchema` a relationship field's `inlineColumns` takes.
+ * That is a form view's `subforms` (`FormViewSchema.subforms`, on a view
+ * container's `form` and on every `formViews` entry) and, since #20928, an
+ * `object-master-detail-form` page block's `details`
+ * (`ComponentPropsMap['object-master-detail-form']`). On both, `columns` is the
+ * same `InlineGridColumnSchema` a relationship field's `inlineColumns` takes,
+ * and `amountField` / `relationshipField` / `totalField` mean the same thing.
+ *
+ * A page's slot map also has a `details` key, whose value is one page
+ * component or an array of them. A component carries none of a child entry's
+ * keys at its own level (they sit under its `properties`), so reading it as an
+ * entry credits nothing and skips nothing.
  */
-const CHILD_COLLECTION_KEYS: ReadonlySet<string> = new Set(['subforms']);
+const CHILD_COLLECTION_KEYS: ReadonlySet<string> = new Set(['subforms', 'details']);
 
 /**
  * [#20951] Keys of a child collection entry whose value names a field of the
 
@@ -297,6 +297,7 @@
     "ObjectMapPropsParsed (type)",
     "ObjectMapPropsSchema (const)",
     "ObjectMasterDetailFormProps (type)",
+    "ObjectMasterDetailFormPropsParsed (type)",
     "ObjectMasterDetailFormPropsSchema (const)",
     "ObjectMetricProps (type)",
     "ObjectMetricPropsParsed (type)",
 
@@ -2,8 +2,8 @@
   "description": "Shrink-only ledger of every PUBLISHED JSON Schema that is STILL WIDER than the Zod type it was generated from, because a rule written as `.refine()` reaches the runtime and not the file (#18670). `z.toJSONSchema()` has no arm for a `custom` check: a plain record, the same record with a `.refine()`, and the same record with an ABORTING `.refine()` all project byte-identically (measured on zod 4.4.3, the version packages/spec resolves). So a document one of these files ACCEPTS can still be refused at parse time, and an author -- or an AI -- validating against packages/spec/json-schema/** finds out a release later. Each `sites` path is a position under that schema at which a refinement is dropped; the same paths are written onto the artifact itself as `x-dropped-refinements`. Item 2 closed the first patterns: a refinement DECLARED through the closed list in src/shared/refinement-projection.ts is emitted into the published file, reads `projected` rather than `dropped`, and its row LEAVES this ledger in the same PR -- which is why the ledger shrinks and never grows on a repair. Every refinement outside that closed list stays here, and adding an arm to the list is a public-contract decision, not a refactor. Hand-edited on purpose and with no `gen:` script: a generator would let a new gap be admitted by running a command instead of by a decision, which is the silence this ledger exists to end. Adding, removing or moving a site fails packages/spec/scripts/build-schemas.ts until the line moves with it, and the failure prints the corrected entry in full. ⛔ Do not delete or weaken a refinement to shorten this file -- the runtime rule is correct; it is the projection that is silent, and the remedy is to teach the closed list a NAMED pattern, never to drop the rule.",
   "measured": {
     "zod": "4.4.3",
-    "publishedSchemasWithDroppedRefinements": 212,
-    "droppedRefinementSites": 617,
+    "publishedSchemasWithDroppedRefinements": 213,
+    "droppedRefinementSites": 618,
     "refinementSitesThatDidProject": 369,
     "refinementSitesWithNoJsonFormToCompare": 0
   },
@@ -1354,6 +1354,11 @@
         "filter.element"
       ]
     },
+    "ui/ObjectMasterDetailFormProps": {
+      "sites": [
+        "details.element.columns.element"
+      ]
+    },
     "ui/ObjectMetricProps": {
       "sites": [
         "filter.element"
 
@@ -293,6 +293,7 @@
     "ObjectMapPropsParsed": "src/ui/component.zod.ts#ObjectMapPropsParsed (type)",
     "ObjectMapPropsSchema": "src/ui/component.zod.ts#ObjectMapPropsSchema (const)",
     "ObjectMasterDetailFormProps": "src/ui/component.zod.ts#ObjectMasterDetailFormProps (type)",
+    "ObjectMasterDetailFormPropsParsed": "src/ui/component.zod.ts#ObjectMasterDetailFormPropsParsed (type)",
     "ObjectMasterDetailFormPropsSchema": "src/ui/component.zod.ts#ObjectMasterDetailFormPropsSchema (const)",
     "ObjectMetricProps": "src/ui/component.zod.ts#ObjectMetricProps (type)",
     "ObjectMetricPropsParsed": "src/ui/component.zod.ts#ObjectMetricPropsParsed (type)",