@@ -0,0 +1,12 @@
+---
+'@object-ui/plugin-grid': patch
+---
+
+refactor(plugin-grid): `ObjectGrid`'s authored-input diagnostics move into a sibling hook
+
+Clause-②: no
+Metadata-protocol: none
+
+The three `console.warn` effects that report an unreadable `columns` entry, an unusable `bulkActionDefs` member and a non-positive page size move verbatim out of `ObjectGrid.tsx` into `useObjectGridDiagnostics` (`objectGridDiagnostics.ts`). `ObjectGrid` calls the hook where the effects stood, so its hook order, its warnings and its rendered output do not change. No name is renamed, and the package entry is unchanged.
+
+What to do: nothing.
@@ -79,9 +79,9 @@ import { resolveRowCrudAffordances, resolveRowRecordCrudAffordance } from './row
 import { useRecordCrudVerdicts } from './hooks/useRecordCrudVerdicts';
 import { resolveLegacyRowActions } from './resolveLegacyRowActions';
 import { applyRelationalMeta } from './relationalMetaKeys';
-import { resolveBulkActions, describeUnusableBulkActionDefs, resolvePromotedBulkParams } from './resolveBulkActions';
+import { resolveBulkActions, resolvePromotedBulkParams } from './resolveBulkActions';
 import { partitionBulkRows } from './bulkEligibility';
-import { resolvesToDataColumn, describeUnresolvedColumns } from './columnSpellingDiagnostics';
+import { resolvesToDataColumn } from './columnSpellingDiagnostics';
 import { RowActionMenu, formatActionLabel, planRowActionMenu } from './components/RowActionMenu';
 import { BulkActionBar } from './components/BulkActionBar';
 import { BulkActionDialog } from './components/BulkActionDialog';
@@ -91,10 +91,11 @@ import { findParamsSignature, useResolvedGridFilters } from './objectGridQuery';
 import { type ObjectGridColumn, type ObjectGridColumnDraft, isChipFieldType, normalizeColumns, resolveColumnLabel } from './objectGridColumns';
 import { LinkCell, recordPointerFace, rowRecordId } from './objectGridLinkCell';
 import { useGridTranslation } from './objectGridTranslations';
-import { DEFAULT_DISPLAY_PAGE_SIZE, DEFAULT_FETCH_BATCH_SIZE, DEFAULT_SELECTION_TYPE, NO_GROUPING_REFUSAL, type RowHeightMode, describeNonPositivePageSize, resolvePageSize, resolveRowHeightMode } from './objectGridDefaults';
+import { DEFAULT_DISPLAY_PAGE_SIZE, DEFAULT_FETCH_BATCH_SIZE, DEFAULT_SELECTION_TYPE, NO_GROUPING_REFUSAL, type RowHeightMode, resolvePageSize, resolveRowHeightMode } from './objectGridDefaults';
 import { type BatchSaveOutcome, OCC_TOKEN_FIELD, type RowConflictChoice, type WrittenRowVersion, rowVersionOf, rowVersionToSend } from './objectGridRowVersion';
 import { type ObjectGridColumnState, type ObjectGridExternalPaginationProps, type ObjectGridFooterSummary } from './objectGridProps';
 import { FooterSummaryReport } from './objectGridFooterSummaryReport';
+import { useObjectGridDiagnostics } from './objectGridDiagnostics';
 export type { RetiredListColumnKey, ObjectGridColumnHolds, ObjectGridColumnDraft, ObjectGridColumn } from './objectGridColumns';
 export type { ObjectGridColumnState, ObjectGridFooterSummary, ObjectGridExternalPaginationProps } from './objectGridProps';
 
@@ -2624,84 +2625,9 @@ export const ObjectGrid: React.FC<ObjectGridComponentProps> = ({
     wholeSetSummary.row,
   );
 
-  // An authored column the renderer cannot read now says so, instead of just
-  // not being there (objectui#5349 — the Q2 objectui#5068 deferred).
-  //
-  // #5068 made `ListColumnSchema`'s `field` / `label` the only spelling read
-  // here, which is right; what it left behind was the receipt. A column
-  // authored `{ accessorKey, header }` (or with no `field` at all) is dropped
-  // by `resolvesToDataColumn` above, and until this effect landed the author
-  // saw no error, no warning and no empty header — just a grid with its
-  // row-number column and no data columns. Same defect shape #5068 exists to
-  // fix, one level down: renderer and author disagree, author gets a success
-  // receipt.
-  //
-  // Scope, deliberately narrow: this reads the `columns` INPUT and nothing
-  // else. It never asks whether the grid found ROWS, because a grid legitimately
-  // draws them from five different places (inline `data` array, `data.provider:
-  // 'value'`, legacy `staticData`, `bind`, or a host that owns the fetch and
-  // passes the window down as a `data` React prop). A predicate that consulted
-  // those would eventually paint a configuration error over a working grid.
-  // `hidden: true` is authored intent and is never reported.
-  //
-  // Channel: the same one `ObjectGrid` already uses for "you declared it, the
-  // renderer dropped it" — a `useEffect` keyed on the schema slice and one
-  // `console.warn` prefixed `[ObjectUI] ObjectGrid <topic>:` (see the export
-  // format warning below) — rather than a second, differently-shaped one.
-  const columnDiagnosticBlockType = (schema as { type?: unknown }).type;
-  const columnDiagnosticLabel = schema.label ?? (schema as { title?: unknown }).title;
-  useEffect(() => {
-    const message = describeUnresolvedColumns(schema.columns, {
-      blockType: columnDiagnosticBlockType,
-      objectName: schema.objectName,
-      label: columnDiagnosticLabel,
-    });
-    if (message) console.warn(message);
-  }, [schema.columns, columnDiagnosticBlockType, schema.objectName, columnDiagnosticLabel]);
-
-  // [objectui#8730] The same channel, for the sibling failure on
-  // `bulkActionDefs`. A member that is not a usable def (a bare action name —
-  // the OTHER key's vocabulary — or `null`, a number, `{}`, `{ name: '' }`) is
-  // skipped by `resolveBulkActions`; before that guard it reached the bar and
-  // `formatActionLabel(undefined)` threw during render, so the author's first
-  // multi-row selection lost the whole selection bar.
-  //
-  // The skip alone would only relocate the failure into silence — which is what
-  // the mirror direction already does (`bulkActions: [{ name: 'approve' }]`,
-  // stepped over by the `typeof name !== 'string'` guard). Saying which member
-  // was dropped, and that a bare name belongs in `bulkActions`, is what makes
-  // this a diagnosis rather than a quieter version of the same defect. One
-  // `console.warn` per authored array, keyed on it — NOT a second guard: the
-  // predicate lives once, in `resolveBulkActions`, and this reads it.
-  const bulkDefsDiagnosticSlice = (schema as { bulkActionDefs?: unknown }).bulkActionDefs;
-  useEffect(() => {
-    const message = describeUnusableBulkActionDefs(bulkDefsDiagnosticSlice, {
-      blockType: columnDiagnosticBlockType,
-      objectName: schema.objectName,
-      label: columnDiagnosticLabel,
-    });
-    if (message) console.warn(message);
-  }, [bulkDefsDiagnosticSlice, columnDiagnosticBlockType, schema.objectName, columnDiagnosticLabel]);
-
-  // [objectui#9853] The same channel again, for a `pagination.pageSize` (or the
-  // deprecated flat shorthand) that is not a positive integer. `resolvePageSize`
-  // drops such a value at all three read points and uses the site's default; on
-  // its own that is a quieter version of the defect, because substituting a
-  // number the author never wrote is exactly what the flat site already did in
-  // silence. This is the half that makes it a diagnosis.
-  //
-  // Keyed on the authored slice, so it is one warning per declaration and not
-  // one per render. NOT a second guard — the predicate lives once, in
-  // `isUsablePageSize`, and this reads it.
-  const pageSizeDiagnosticObject = schema.pagination;
-  const pageSizeDiagnosticFlat = schema.pageSize;
-  useEffect(() => {
-    const message = describeNonPositivePageSize(
-      { pagination: pageSizeDiagnosticObject, pageSize: pageSizeDiagnosticFlat },
-      { blockType: columnDiagnosticBlockType, objectName: schema.objectName },
-    );
-    if (message) console.warn(message);
-  }, [pageSizeDiagnosticObject, pageSizeDiagnosticFlat, columnDiagnosticBlockType, schema.objectName]);
+  // The authored-input diagnostics (`columns`, `bulkActionDefs`, page size),
+  // three `console.warn` effects, run here in hook order (`./objectGridDiagnostics`).
+  useObjectGridDiagnostics(schema);
 
   const generateColumns = useCallback((): ObjectGridColumnDraft[] => {
     // objectui#11815 — the host's verdict on a declared deadline's
 
@@ -0,0 +1,98 @@
+/**
+ * The authored-input diagnostics of `ObjectGrid` (`./ObjectGrid.tsx`): the three
+ * `console.warn` effects that report an unreadable `columns` entry, an unusable
+ * `bulkActionDefs` member and a non-positive page size, moved out of that file
+ * verbatim into a hook (objectstack#25994, slice 3).
+ */
+
+import { useEffect } from 'react';
+import type { ObjectGridSchema } from '@object-ui/types';
+import { describeUnresolvedColumns } from './columnSpellingDiagnostics';
+import { describeUnusableBulkActionDefs } from './resolveBulkActions';
+import { describeNonPositivePageSize } from './objectGridDefaults';
+
+/**
+ * Runs `ObjectGrid`'s authored-input diagnostics. It declares no state and
+ * returns nothing. `ObjectGrid` calls it where the three effects used to stand,
+ * so the order of the component's hooks does not change.
+ */
+export function useObjectGridDiagnostics(schema: ObjectGridSchema): void {
+  // An authored column the renderer cannot read now says so, instead of just
+  // not being there (objectui#5349 — the Q2 objectui#5068 deferred).
+  //
+  // #5068 made `ListColumnSchema`'s `field` / `label` the only spelling read
+  // here, which is right; what it left behind was the receipt. A column
+  // authored `{ accessorKey, header }` (or with no `field` at all) is dropped
+  // by `resolvesToDataColumn` above, and until this effect landed the author
+  // saw no error, no warning and no empty header — just a grid with its
+  // row-number column and no data columns. Same defect shape #5068 exists to
+  // fix, one level down: renderer and author disagree, author gets a success
+  // receipt.
+  //
+  // Scope, deliberately narrow: this reads the `columns` INPUT and nothing
+  // else. It never asks whether the grid found ROWS, because a grid legitimately
+  // draws them from five different places (inline `data` array, `data.provider:
+  // 'value'`, legacy `staticData`, `bind`, or a host that owns the fetch and
+  // passes the window down as a `data` React prop). A predicate that consulted
+  // those would eventually paint a configuration error over a working grid.
+  // `hidden: true` is authored intent and is never reported.
+  //
+  // Channel: the same one `ObjectGrid` already uses for "you declared it, the
+  // renderer dropped it" — a `useEffect` keyed on the schema slice and one
+  // `console.warn` prefixed `[ObjectUI] ObjectGrid <topic>:` (see the export
+  // format warning below) — rather than a second, differently-shaped one.
+  const columnDiagnosticBlockType = (schema as { type?: unknown }).type;
+  const columnDiagnosticLabel = schema.label ?? (schema as { title?: unknown }).title;
+  useEffect(() => {
+    const message = describeUnresolvedColumns(schema.columns, {
+      blockType: columnDiagnosticBlockType,
+      objectName: schema.objectName,
+      label: columnDiagnosticLabel,
+    });
+    if (message) console.warn(message);
+  }, [schema.columns, columnDiagnosticBlockType, schema.objectName, columnDiagnosticLabel]);
+
+  // [objectui#8730] The same channel, for the sibling failure on
+  // `bulkActionDefs`. A member that is not a usable def (a bare action name —
+  // the OTHER key's vocabulary — or `null`, a number, `{}`, `{ name: '' }`) is
+  // skipped by `resolveBulkActions`; before that guard it reached the bar and
+  // `formatActionLabel(undefined)` threw during render, so the author's first
+  // multi-row selection lost the whole selection bar.
+  //
+  // The skip alone would only relocate the failure into silence — which is what
+  // the mirror direction already does (`bulkActions: [{ name: 'approve' }]`,
+  // stepped over by the `typeof name !== 'string'` guard). Saying which member
+  // was dropped, and that a bare name belongs in `bulkActions`, is what makes
+  // this a diagnosis rather than a quieter version of the same defect. One
+  // `console.warn` per authored array, keyed on it — NOT a second guard: the
+  // predicate lives once, in `resolveBulkActions`, and this reads it.
+  const bulkDefsDiagnosticSlice = (schema as { bulkActionDefs?: unknown }).bulkActionDefs;
+  useEffect(() => {
+    const message = describeUnusableBulkActionDefs(bulkDefsDiagnosticSlice, {
+      blockType: columnDiagnosticBlockType,
+      objectName: schema.objectName,
+      label: columnDiagnosticLabel,
+    });
+    if (message) console.warn(message);
+  }, [bulkDefsDiagnosticSlice, columnDiagnosticBlockType, schema.objectName, columnDiagnosticLabel]);
+
+  // [objectui#9853] The same channel again, for a `pagination.pageSize` (or the
+  // deprecated flat shorthand) that is not a positive integer. `resolvePageSize`
+  // drops such a value at all three read points and uses the site's default; on
+  // its own that is a quieter version of the defect, because substituting a
+  // number the author never wrote is exactly what the flat site already did in
+  // silence. This is the half that makes it a diagnosis.
+  //
+  // Keyed on the authored slice, so it is one warning per declaration and not
+  // one per render. NOT a second guard — the predicate lives once, in
+  // `isUsablePageSize`, and this reads it.
+  const pageSizeDiagnosticObject = schema.pagination;
+  const pageSizeDiagnosticFlat = schema.pageSize;
+  useEffect(() => {
+    const message = describeNonPositivePageSize(
+      { pagination: pageSizeDiagnosticObject, pageSize: pageSizeDiagnosticFlat },
+      { blockType: columnDiagnosticBlockType, objectName: schema.objectName },
+    );
+    if (message) console.warn(message);
+  }, [pageSizeDiagnosticObject, pageSizeDiagnosticFlat, columnDiagnosticBlockType, schema.objectName]);
+}