@@ -0,0 +1,11 @@
+---
+'@object-ui/app-shell': patch
+---
+
+The dataset designer no longer writes `field: ''` for a row whose Field box is blank (objectui#11402).
+
+New dimension and measure rows used to be seeded with `field: ''`, so a Studio author who added a plain row-count measure and left the Field box blank saved `field: ''`. That value means nothing to any reader: the analytics query answered 500 on the ObjectQL strategy for a `count` measure carrying it, and the narrowed dataset schema (objectstack-ai/objectstack#21240) refuses it at save.
+
+- New rows are seeded without a `field` key, and a blank Field value removes the key instead of storing `''`. A `count` measure with no field therefore saves the one spelling the spec has for count(*): the key absent.
+- A dimension needs a field. A dimension whose Field box is blank (including a stored `field: ''`) is reported to the editor's Save gate, the same channel that holds Save, autosave and the shortcut for a CEL expression that does not parse, until a field is picked. Its Field label carries the designer's required marker.
+- Nothing is filled in on the author's behalf: no `id` or other default field is written.
@@ -0,0 +1,213 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * objectui#11402 — a blank Field box writes no `field` key.
+ *
+ * The dataset inspector used to seed every new row with `field: ''`, so a
+ * Studio author who added a plain row-count measure and left the Field box
+ * blank saved `field: ''`. The spec has one spelling for "no field" on a
+ * measure — the key is ABSENT (`DatasetMeasureSchema.field` is optional, and
+ * only `count` may omit it) — and a dimension's `field` is required, so an
+ * empty string is a value no reader can use: the analytics door answered 500
+ * on the ObjectQL strategy for a `count` measure with `field: ''`, and the
+ * narrowed spec (objectstack-ai/objectstack#21240) refuses it at save.
+ *
+ * The rulings this file pins (triage on objectui#11402):
+ *   - new rows are seeded without a `field` key;
+ *   - a measure with a blank Field box writes no `field`;
+ *   - a dimension with a blank Field box shows as incomplete and is not saved
+ *     with `''` — it is reported on the inspector's blocking-issue channel, the
+ *     one the host's Save gate already reads (objectui#4527 / objectui#6900);
+ *   - no `id` default is written on the author's behalf.
+ *
+ * The "saved" body below is the draft as the host holds it — patches merged
+ * shallowly, exactly as `ResourceEditPage` applies `onPatch` — sent through a
+ * JSON round trip, because the `dataset` type declares no `fromDraft`
+ * serialiser, so that draft IS the body the save sends.
+ */
+
+import * as React from 'react';
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { render, screen, cleanup, fireEvent, waitFor } from '@testing-library/react';
+import { DatasetSchema } from '@objectstack/spec/ui';
+
+// Stub the catalog hooks so the inspector renders without a MetadataClient /
+// network — the sibling suites' stubs, plus two catalog fields to pick from.
+vi.mock('./useDatasetFields', () => ({
+  useObjectOptions: () => ({ options: [], loading: false }),
+  useDatasetFieldCatalog: () => ({
+    relationships: [],
+    fieldOptions: [
+      { value: 'region', label: 'Region', type: 'text' },
+      { value: 'amount', label: 'Amount', type: 'currency' },
+    ],
+    loading: false,
+  }),
+  useDatasetUsage: () => ({ reports: 0, dashboards: 0, loading: false }),
+  fieldTypeToDimensionType: (t: string) => (t === 'date' ? 'date' : 'string'),
+}));
+
+import { DatasetDefaultInspector, writeRowField } from './DatasetDefaultInspector';
+
+afterEach(cleanup);
+
+type Draft = Record<string, unknown> & {
+  dimensions?: Array<Record<string, unknown>>;
+  measures?: Array<Record<string, unknown>>;
+};
+
+const BASE: Draft = { name: 'sales', label: 'Sales', object: 'opportunity', dimensions: [], measures: [] };
+
+/** A host that holds the draft and merges each patch the way `ResourceEditPage` does. */
+function mountHost(initial: Draft) {
+  const seen: { draft: Draft; blocking: number[] } = { draft: initial, blocking: [] };
+  function Host() {
+    const [draft, setDraft] = React.useState<Draft>(initial);
+    seen.draft = draft;
+    return (
+      <DatasetDefaultInspector
+        type="dataset"
+        name="sales"
+        locale="en-US"
+        readOnly={false}
+        draft={draft}
+        onPatch={(patch) => setDraft((d) => ({ ...d, ...patch }))}
+        onBlockingIssuesChange={(count) => seen.blocking.push(count)}
+      />
+    );
+  }
+  render(<Host />);
+  return seen;
+}
+
+/** The body the save sends: the held draft through the JSON wire. */
+const savedBody = (draft: Draft): Draft => JSON.parse(JSON.stringify(draft));
+
+async function pickSelectOption(label: string, option: string) {
+  fireEvent.keyDown(screen.getByRole('combobox', { name: label }), { key: 'ArrowDown' });
+  await waitFor(() => expect(screen.queryAllByRole('option').length).toBeGreaterThan(0));
+  fireEvent.click(screen.getByRole('option', { name: option }));
+}
+
+async function pickComboOption(label: string, value: string) {
+  fireEvent.click(screen.getByRole('combobox', { name: label }));
+  await waitFor(() => expect(screen.queryAllByRole('option').length).toBeGreaterThan(0));
+  const item = screen.getAllByRole('option').find((o) => o.textContent?.startsWith(value));
+  expect(item, `the catalog option ${value}`).toBeTruthy();
+  fireEvent.click(item!);
+}
+
+describe('DatasetDefaultInspector — new rows carry no `field` key (objectui#11402)', () => {
+  it('seeds a new measure row with no `field` key', () => {
+    const onPatch = vi.fn();
+    render(<DatasetDefaultInspector type="dataset" name="sales" locale="en-US" readOnly={false} draft={BASE} onPatch={onPatch} />);
+    fireEvent.click(screen.getByText('Add measure'));
+    // `toStrictEqual`, not `toEqual`: a key present with the value `undefined`
+    // must fail here too — the row has to be built without it.
+    expect(onPatch.mock.calls[0][0].measures[0]).toStrictEqual({ name: '', aggregate: 'sum' });
+  });
+
+  it('seeds a new dimension row with no `field` key — and no `id` default either', () => {
+    const onPatch = vi.fn();
+    render(<DatasetDefaultInspector type="dataset" name="sales" locale="en-US" readOnly={false} draft={BASE} onPatch={onPatch} />);
+    fireEvent.click(screen.getByText('Add dimension'));
+    expect(onPatch.mock.calls[0][0].dimensions[0]).toStrictEqual({ name: '', type: 'string' });
+  });
+});
+
+describe('DatasetDefaultInspector — a blank Field box on a measure writes no `field` (objectui#11402)', () => {
+  it('⭐ a measure added and saved with a blank Field box carries no `field`, and the saved dataset parses under DatasetSchema', async () => {
+    const seen = mountHost(BASE);
+    fireEvent.click(screen.getByText('Add measure'));
+    fireEvent.change(screen.getByPlaceholderText('e.g. revenue'), { target: { value: 'row_count' } });
+    await pickSelectOption('Aggregate', 'count');
+
+    const held = seen.draft.measures![0];
+    expect(Object.hasOwn(held, 'field'), 'the held row has no `field` key at all').toBe(false);
+    const body = savedBody(seen.draft);
+    expect(body.measures![0]).toStrictEqual({ name: 'row_count', aggregate: 'count' });
+
+    const parsed = DatasetSchema.safeParse(body);
+    expect(parsed.success, JSON.stringify(parsed.error?.issues)).toBe(true);
+    // Control: the same parse refuses a field-less NON-count measure, so the
+    // green above is a verdict the schema could have withheld.
+    const control = DatasetSchema.safeParse({ ...body, measures: [{ name: 'row_count', aggregate: 'sum' }] });
+    expect(control.success).toBe(false);
+  });
+
+  it('a field-less measure is not held: only the dimension side is incomplete without a field', () => {
+    const seen = mountHost({
+      ...BASE,
+      dimensions: [{ name: 'region', field: 'region', type: 'string' }],
+      measures: [{ name: 'row_count', aggregate: 'count' }],
+    });
+    expect(seen.blocking.at(-1)).toBe(0);
+  });
+
+  it('a cleared Field value is written as an absent key, never as `\'\'`', () => {
+    // Typed as the inspector's own row shape: a field-less literal shares no
+    // key with `{ field?: string }`, so left to inference it reads as a weak
+    // type and `tsc -p tsconfig.test.json` refuses its other keys.
+    type Row = { name: string; aggregate: string; field?: string };
+    const filled: Row = { name: 'n', aggregate: 'sum', field: 'amount' };
+    const fieldless: Row = { name: 'n', aggregate: 'sum' };
+    expect(writeRowField(filled, '')).toStrictEqual({ name: 'n', aggregate: 'sum' });
+    expect(writeRowField(filled, '   ')).toStrictEqual({ name: 'n', aggregate: 'sum' });
+    expect(writeRowField(fieldless, 'amount')).toStrictEqual({ name: 'n', aggregate: 'sum', field: 'amount' });
+  });
+});
+
+describe('DatasetDefaultInspector — a blank-Field dimension is held as incomplete (objectui#11402)', () => {
+  it('⭐ a dimension added with a blank Field box is reported to the Save gate until a field is picked', async () => {
+    const seen = mountHost(BASE);
+    expect(seen.blocking.at(-1), 'nothing to hold before the row exists').toBe(0);
+
+    fireEvent.click(screen.getByText('Add dimension'));
+    expect(seen.blocking.at(-1), 'the field-less dimension is a blocking issue').toBe(1);
+    expect(Object.hasOwn(seen.draft.dimensions![0], 'field'), 'and it is not held as `field: \'\'`').toBe(false);
+    // Shown as incomplete: while the box is blank, the Field label carries the
+    // designer's required marker (objectui#10948) — the spec requires a
+    // dimension's field.
+    const markerOnFieldLabel = () => screen.getByText('Field').closest('label')?.querySelector('[data-required-marker="true"]');
+    expect(markerOnFieldLabel(), 'the required marker on the blank Field label').toBeTruthy();
+
+    await pickComboOption('Field', 'region');
+    expect(seen.draft.dimensions![0]).toMatchObject({ name: 'region', field: 'region', type: 'string' });
+    expect(seen.blocking.at(-1), 'a picked field releases the hold').toBe(0);
+    expect(markerOnFieldLabel(), 'a complete row shows the plain label').toBeFalsy();
+  });
+
+  it('the hold is never stricter than the spec: DatasetSchema refuses the field-less dimension it holds, and takes it once a field is picked', () => {
+    // The host keeps a verdict the server also returns advisory, because a
+    // client gate STRICTER than the server would wedge Save on a body the
+    // server takes (`ResourceEditPage`, the note above `blockingReport`). This
+    // hold is safe on that count only while the spec itself refuses a
+    // dimension without a `field` — if `DatasetDimensionSchema.field` ever
+    // turns optional, this goes red and the hold has to be revisited. (A
+    // stored `field: ''` is the one row it holds that this spec still takes:
+    // that one is ruled — not saved with `''` — and the Field box on screen
+    // repairs it, so it cannot wedge.)
+    const held = DatasetSchema.safeParse({ ...BASE, dimensions: [{ name: 'region', type: 'string' }] });
+    expect(held.success).toBe(false);
+    expect(held.error?.issues.map((i) => i.path.join('.'))).toContain('dimensions.0.field');
+    const picked = DatasetSchema.safeParse({ ...BASE, dimensions: [{ name: 'region', field: 'region', type: 'string' }] });
+    expect(picked.success, JSON.stringify(picked.error?.issues)).toBe(true);
+  });
+
+  it('a stored dimension whose field is `\'\'` is held too, so it is not saved again as `\'\'`', () => {
+    const seen = mountHost({ ...BASE, dimensions: [{ name: 'region', field: '', type: 'string' }] });
+    expect(seen.blocking.at(-1)).toBe(1);
+  });
+
+  it('counts each incomplete dimension once', () => {
+    const seen = mountHost({
+      ...BASE,
+      dimensions: [
+        { name: 'a', type: 'string' },
+        { name: 'b', field: 'region', type: 'string' },
+        { name: 'c', field: '', type: 'string' },
+      ],
+    });
+    expect(seen.blocking.at(-1)).toBe(2);
+  });
+});