diff --git a/examples/react/kitchen-sink/src/main.tsx b/examples/react/kitchen-sink/src/main.tsx
index dec9ab4263..43a319eafa 100644
--- a/examples/react/kitchen-sink/src/main.tsx
+++ b/examples/react/kitchen-sink/src/main.tsx
@@ -693,6 +693,7 @@ function App() {
       },
       keepPinnedRows: true,
       debugTable: true,
+      autoResetExpanded: false, // keep expanded rows during filtering changes
     },
     (state) => state, // default selector
   )
diff --git a/packages/table-core/src/core/columns/coreColumnsFeature.utils.ts b/packages/table-core/src/core/columns/coreColumnsFeature.utils.ts
index 6803f48a86..5901595f1c 100644
--- a/packages/table-core/src/core/columns/coreColumnsFeature.utils.ts
+++ b/packages/table-core/src/core/columns/coreColumnsFeature.utils.ts
@@ -218,7 +218,7 @@ export function table_getAllLeafColumns<
     table,
     'getOrderColumns',
     table_getOrderColumnsFn,
-  )(leafColumns)
+  )(leafColumns) as Array<Column<TFeatures, TData, unknown>>
 }
 
 /**
diff --git a/packages/table-core/src/core/headers/buildHeaderGroups.ts b/packages/table-core/src/core/headers/buildHeaderGroups.ts
index 386858caee..f0c913a117 100644
--- a/packages/table-core/src/core/headers/buildHeaderGroups.ts
+++ b/packages/table-core/src/core/headers/buildHeaderGroups.ts
@@ -113,7 +113,9 @@ export function buildHeaderGroups<
         pendingParentHeaders.push(header)
       }
 
-      headerGroup.headers.push(headerToGroup)
+      headerGroup.headers.push(
+        headerToGroup as Header<TFeatures, TData, unknown>,
+      )
       headerToGroup.headerGroup = headerGroup
     })
 
diff --git a/packages/table-core/src/features/column-filtering/columnFilteringFeature.utils.ts b/packages/table-core/src/features/column-filtering/columnFilteringFeature.utils.ts
index 8b759affa7..fb09fe8f4a 100644
--- a/packages/table-core/src/features/column-filtering/columnFilteringFeature.utils.ts
+++ b/packages/table-core/src/features/column-filtering/columnFilteringFeature.utils.ts
@@ -323,7 +323,7 @@ export function shouldAutoRemoveFilter<
 ) {
   return (
     (filterFn && filterFn.autoRemove
-      ? filterFn.autoRemove(value, column as Column_Internal<TFeatures, TData>)
+      ? filterFn.autoRemove(value, column as any)
       : false) ||
     typeof value === 'undefined' ||
     (typeof value === 'string' && !value)
diff --git a/packages/table-core/src/features/column-pinning/columnPinningFeature.utils.ts b/packages/table-core/src/features/column-pinning/columnPinningFeature.utils.ts
index 069063420d..4bb3f4305f 100644
--- a/packages/table-core/src/features/column-pinning/columnPinningFeature.utils.ts
+++ b/packages/table-core/src/features/column-pinning/columnPinningFeature.utils.ts
@@ -13,7 +13,7 @@ import type { Row } from '../../types/Row'
 import type { CellData, RowData, Updater } from '../../types/type-utils'
 import type { TableFeatures } from '../../types/TableFeatures'
 import type { Table_Internal } from '../../types/Table'
-import type { Column_Internal } from '../../types/Column'
+import type { Column, Column_Internal } from '../../types/Column'
 import type {
   ColumnPinningPosition,
   ColumnPinningState,
@@ -364,15 +364,11 @@ export function table_getLeftHeaderGroups<
   TData extends RowData,
 >(table: Table_Internal<TFeatures, TData>) {
   const allColumns = table.getAllColumns()
-  const leafColumnsById = table.getAllLeafColumnsById() as Record<
-    string,
-    Column_Internal<TFeatures, TData, unknown>
-  >
+  const leafColumnsById = table.getAllLeafColumnsById()
   const { left } =
     table.atoms.columnPinning?.get() ?? getDefaultColumnPinningState()
 
-  const orderedLeafColumns: Array<Column_Internal<TFeatures, TData, unknown>> =
-    []
+  const orderedLeafColumns: Array<Column<TFeatures, TData, unknown>> = []
   for (let i = 0; i < left.length; i++) {
     const column = leafColumnsById[left[i]!]
     if (
@@ -402,15 +398,11 @@ export function table_getRightHeaderGroups<
   TData extends RowData,
 >(table: Table_Internal<TFeatures, TData>) {
   const allColumns = table.getAllColumns()
-  const leafColumnsById = table.getAllLeafColumnsById() as Record<
-    string,
-    Column_Internal<TFeatures, TData, unknown>
-  >
+  const leafColumnsById = table.getAllLeafColumnsById()
   const { right } =
     table.atoms.columnPinning?.get() ?? getDefaultColumnPinningState()
 
-  const orderedLeafColumns: Array<Column_Internal<TFeatures, TData, unknown>> =
-    []
+  const orderedLeafColumns: Array<Column<TFeatures, TData, unknown>> = []
   for (let i = 0; i < right.length; i++) {
     const column = leafColumnsById[right[i]!]
     if (
@@ -446,7 +438,7 @@ export function table_getCenterHeaderGroups<
     table,
     'getVisibleLeafColumns',
     table_getVisibleLeafColumns,
-  ) as unknown as Array<Column_Internal<TFeatures, TData, unknown>>
+  )
   const { left, right } =
     table.atoms.columnPinning?.get() ?? getDefaultColumnPinningState()
   const leftAndRight: Array<string> = [...left, ...right]
diff --git a/packages/table-core/src/features/column-resizing/columnResizingFeature.types.ts b/packages/table-core/src/features/column-resizing/columnResizingFeature.types.ts
index d8c827ce66..1c03a4e89d 100644
--- a/packages/table-core/src/features/column-resizing/columnResizingFeature.types.ts
+++ b/packages/table-core/src/features/column-resizing/columnResizingFeature.types.ts
@@ -54,11 +54,8 @@ export interface Table_ColumnResizing {
   resetHeaderSizeInfo: (defaultState?: boolean) => void
   /**
    * Updates transient resize interaction state with a next state or updater function.
-   *
-   * The lowercase `c` in this API name matches the current generated v9 table
-   * API for the `columnResizing` state slice.
    */
-  setcolumnResizing: (updater: Updater<columnResizingState>) => void
+  setColumnResizing: (updater: Updater<columnResizingState>) => void
 }
 
 export interface ColumnDef_ColumnResizing {
diff --git a/packages/table-core/src/features/global-filtering/globalFilteringFeature.utils.ts b/packages/table-core/src/features/global-filtering/globalFilteringFeature.utils.ts
index 49abdebd19..588475f7f7 100644
--- a/packages/table-core/src/features/global-filtering/globalFilteringFeature.utils.ts
+++ b/packages/table-core/src/features/global-filtering/globalFilteringFeature.utils.ts
@@ -26,7 +26,7 @@ export function column_getCanGlobalFilter<
     (column.columnDef.enableGlobalFilter ?? true) &&
     (column.table.options.enableGlobalFilter ?? true) &&
     (column.table.options.enableFilters ?? true) &&
-    (column.table.options.getColumnCanGlobalFilter?.(column) ?? true) &&
+    (column.table.options.getColumnCanGlobalFilter?.(column as any) ?? true) &&
     !!column.accessorFn
   )
 }
diff --git a/packages/table-core/src/helpers/columnHelper.ts b/packages/table-core/src/helpers/columnHelper.ts
index beaea18690..e5328cda35 100644
--- a/packages/table-core/src/helpers/columnHelper.ts
+++ b/packages/table-core/src/helpers/columnHelper.ts
@@ -10,10 +10,10 @@ import type {
   IdentifiedColumnDef,
 } from '../types/ColumnDef'
 
-export type ColumnHelper<
-  TFeatures extends TableFeatures,
-  TData extends RowData,
-> = {
+export interface ColumnHelper<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData,
+> {
   /**
    * Creates a data column definition with an accessor key or function to extract the cell value.
    * @example
diff --git a/packages/table-core/src/types/Column.ts b/packages/table-core/src/types/Column.ts
index c98f24cd1d..59d12ad91d 100644
--- a/packages/table-core/src/types/Column.ts
+++ b/packages/table-core/src/types/Column.ts
@@ -42,10 +42,10 @@ export type Column<
 > = Column_Core<TFeatures, TData, TValue> &
   ExtractFeatureMapTypes<TFeatures, Column_FeatureMap<TFeatures, TData>>
 
-export type Column_Internal<
-  TFeatures extends TableFeatures,
-  TData extends RowData,
+export interface Column_Internal<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData,
   TValue = unknown,
-> = Column<TFeatures, TData, TValue> & {
+> extends Omit<Column_Core<TFeatures, TData, TValue>, 'columnDef'> {
   columnDef: ColumnDefBase_All<TFeatures, TData, TValue>
 }
diff --git a/packages/table-core/src/types/HeaderGroup.ts b/packages/table-core/src/types/HeaderGroup.ts
index eb22ce5ea0..748f3d6a74 100644
--- a/packages/table-core/src/types/HeaderGroup.ts
+++ b/packages/table-core/src/types/HeaderGroup.ts
@@ -7,7 +7,7 @@ export interface HeaderGroup_Core<
   in out TData extends RowData,
 > extends HeaderGroup_Header<TFeatures, TData> {}
 
-export type HeaderGroup<
-  TFeatures extends TableFeatures,
-  TData extends RowData,
-> = HeaderGroup_Core<TFeatures, TData>
+export interface HeaderGroup<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData,
+> extends HeaderGroup_Core<TFeatures, TData> {}
diff --git a/packages/table-core/src/types/RowModel.ts b/packages/table-core/src/types/RowModel.ts
index 217d2fb3af..04a413a3dc 100644
--- a/packages/table-core/src/types/RowModel.ts
+++ b/packages/table-core/src/types/RowModel.ts
@@ -33,10 +33,10 @@ export type CachedRowModels<
   CachedRowModels_FeatureMap<TFeatures, TData>
 >
 
-export type CachedRowModel_All<
-  TFeatures extends TableFeatures,
-  TData extends RowData = any,
-> = Partial<
+export interface CachedRowModel_All<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData = any,
+> extends Partial<
   CachedRowModel_Core<TFeatures, TData> &
     CachedRowModel_Expanded<TFeatures, TData> &
     CachedRowModel_Faceted<TFeatures, TData> &
@@ -44,4 +44,4 @@ export type CachedRowModel_All<
     CachedRowModel_Grouped<TFeatures, TData> &
     CachedRowModel_Paginated<TFeatures, TData> &
     CachedRowModel_Sorted<TFeatures, TData>
->
+> {}
diff --git a/packages/table-core/src/types/RowModelFns.ts b/packages/table-core/src/types/RowModelFns.ts
index 27d880376f..09faeac541 100644
--- a/packages/table-core/src/types/RowModelFns.ts
+++ b/packages/table-core/src/types/RowModelFns.ts
@@ -22,11 +22,11 @@ export type RowModelFns<
   ExtractFeatureMapTypes<TFeatures, RowModelFns_FeatureMap<TFeatures, TData>>
 >
 
-export type RowModelFns_All<
-  TFeatures extends TableFeatures,
-  TData extends RowData,
-> = Partial<
+export interface RowModelFns_All<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData,
+> extends Partial<
   RowModelFns_ColumnFiltering<TFeatures, TData> &
     RowModelFns_ColumnGrouping<TFeatures, TData> &
     RowModelFns_RowSorting<TFeatures, TData>
->
+> {}
diff --git a/packages/table-core/src/types/Table.ts b/packages/table-core/src/types/Table.ts
index 84c7bfaa7e..829b657344 100644
--- a/packages/table-core/src/types/Table.ts
+++ b/packages/table-core/src/types/Table.ts
@@ -36,14 +36,16 @@ import type { DebugOptions, TableOptions_All } from './TableOptions'
  * The core table object that only includes the core table functionality such as column, header, row, and table APIS.
  * No features are included.
  */
-export type Table_Core<
-  TFeatures extends TableFeatures,
-  TData extends RowData,
-> = Table_Table<TFeatures, TData> &
-  Table_Columns<TFeatures, TData> &
-  Table_Rows<TFeatures, TData> &
-  Table_RowModels<TFeatures, TData> &
-  Table_Headers<TFeatures, TData>
+export interface Table_Core<
+  in out TFeatures extends TableFeatures,
+  in out TData extends RowData,
+>
+  extends
+    Table_Table<TFeatures, TData>,
+    Table_Columns<TFeatures, TData>,
+    Table_Rows<TFeatures, TData>,
+    Table_RowModels<TFeatures, TData>,
+    Table_Headers<TFeatures, TData> {}
 
 export interface Table_FeatureMap<
   in out TFeatures extends TableFeatures,
@@ -88,15 +90,6 @@ type Table_InternalBroadenedKeys =
 
 /**
  * Internal broad table shape used by feature implementations.
- *
- * Declared as an interface extending every stock feature's table API (rather
- * than the feature-conditional `Table` intersection) so that the compiler can
- * relate `Table_Internal` instantiations nominally instead of structurally
- * re-expanding the feature-map conditional for every internal call site.
- * Mirrors the `*_All` convention used for options, state, and row models.
- * Type parameters are annotated `in out` (invariant) so the checker can relate
- * instantiations by their type arguments without measuring variance or falling
- * back to member-by-member structural comparison.
  */
 export interface Table_Internal<
   in out TFeatures extends TableFeatures,
@@ -107,21 +100,7 @@ export interface Table_Internal<
     Table_Columns<TFeatures, TData>,
     Table_Rows<TFeatures, TData>,
     Table_RowModels<TFeatures, TData>,
-    Table_Headers<TFeatures, TData>,
-    Table_ColumnFiltering,
-    Table_ColumnGrouping<TFeatures, TData>,
-    Table_ColumnOrdering<TFeatures, TData>,
-    Table_ColumnPinning<TFeatures, TData>,
-    Table_ColumnResizing,
-    Table_ColumnSizing,
-    Table_ColumnVisibility<TFeatures, TData>,
-    Table_ColumnFaceting<TFeatures, TData>,
-    Table_GlobalFiltering<TFeatures, TData>,
-    Table_RowExpanding<TFeatures, TData>,
-    Table_RowPagination<TFeatures, TData>,
-    Table_RowPinning<TFeatures, TData>,
-    Table_RowSelection<TFeatures, TData>,
-    Table_RowSorting<TFeatures, TData> {
+    Table_Headers<TFeatures, TData> {
   _rowModels: CachedRowModel_All<TFeatures, TData>
   _rowModelFns: RowModelFns_All<TFeatures, TData>
   options: DebugOptions<TableFeatures> &
diff --git a/packages/table-core/src/types/TableState.ts b/packages/table-core/src/types/TableState.ts
index d8459df545..e3f0b1eaf0 100644
--- a/packages/table-core/src/types/TableState.ts
+++ b/packages/table-core/src/types/TableState.ts
@@ -44,4 +44,18 @@ export type TableState<TFeatures extends TableFeatures> =
  * Feature internals use this when they may need to inspect optional slices owned
  * by other features.
  */
-export type TableState_All = Partial<TableState<TableFeatures>>
+export interface TableState_All extends Partial<
+  TableState_ColumnFiltering &
+    TableState_ColumnGrouping &
+    TableState_ColumnOrdering &
+    TableState_ColumnPinning &
+    TableState_ColumnResizing &
+    TableState_ColumnSizing &
+    TableState_ColumnVisibility &
+    TableState_GlobalFiltering &
+    TableState_RowExpanding &
+    TableState_RowPagination &
+    TableState_RowPinning &
+    TableState_RowSelection &
+    TableState_RowSorting
+> {}
diff --git a/packages/table-core/tests/helpers/rowPinningHelpers.ts b/packages/table-core/tests/helpers/rowPinningHelpers.ts
index 8b1ea4891d..401c57beab 100644
--- a/packages/table-core/tests/helpers/rowPinningHelpers.ts
+++ b/packages/table-core/tests/helpers/rowPinningHelpers.ts
@@ -1,5 +1,9 @@
+import { table } from 'node:console'
 import { vi } from 'vitest'
-import { getDefaultRowPinningState } from '../../src/features/row-pinning/rowPinningFeature.utils'
+import {
+  getDefaultRowPinningState,
+  table_setRowPinning,
+} from '../../src/features/row-pinning/rowPinningFeature.utils'
 import {
   constructTable,
   coreFeatures,
@@ -9,7 +13,14 @@ import {
 import { generateTestData } from '../fixtures/data/generateTestData'
 import { storeReactivityBindings } from '../../src/store-reactivity-bindings'
 import { generateTestTableWithData } from './generateTestTable'
-import type { ColumnDef, RowPinningState, TableOptions } from '../../src'
+import type {
+  ColumnDef,
+  RowPinningState,
+  StockFeatures,
+  TableOptions,
+  Table_Internal,
+  Table_RowPinning,
+} from '../../src'
 import type { Person } from '../fixtures/data/types'
 
 // Define feature set with proper typing
@@ -52,7 +63,8 @@ export function createTableWithPinningState(
 }
 
 export function createTableWithMockOnPinningChange(rowCount = 10): {
-  table: ReturnType<typeof generateTestTableWithData>
+  table: Table_Internal<StockFeatures, Person> &
+    Table_RowPinning<StockFeatures, Person>
   onRowPinningChangeMock: ReturnType<typeof vi.fn>
 } {
   const onRowPinningChangeMock = vi.fn()
@@ -60,7 +72,8 @@ export function createTableWithMockOnPinningChange(rowCount = 10): {
     features: {
       rowPinning: rowPinningFeature,
     },
-  } as any)
+  } as any) as Table_Internal<StockFeatures, Person> &
+    Table_RowPinning<StockFeatures, Person>
   table.options.onRowPinningChange = onRowPinningChangeMock
   return { table, onRowPinningChangeMock }
 }
diff --git a/packages/table-core/tests/implementation/features/row-pinning/rowPinningFeature.test.ts b/packages/table-core/tests/implementation/features/row-pinning/rowPinningFeature.test.ts
index 9a21154b1b..6a86570470 100644
--- a/packages/table-core/tests/implementation/features/row-pinning/rowPinningFeature.test.ts
+++ b/packages/table-core/tests/implementation/features/row-pinning/rowPinningFeature.test.ts
@@ -332,7 +332,7 @@ describe('row methods', () => {
       const { table, onRowPinningChangeMock } =
         createTableWithMockOnPinningChange()
       // Set up initial state with a pinned row
-      table.baseAtoms.rowPinning!.set({
+      table.baseAtoms.rowPinning.set({
         top: [ROW[0]],
         bottom: [],
       })
diff --git a/packages/table-core/tests/unit/core/tableAtoms.test.ts b/packages/table-core/tests/unit/core/tableAtoms.test.ts
index 0670bf8226..d0f2eb4d23 100644
--- a/packages/table-core/tests/unit/core/tableAtoms.test.ts
+++ b/packages/table-core/tests/unit/core/tableAtoms.test.ts
@@ -11,7 +11,10 @@ import { storeReactivityBindings } from '../../../src/store-reactivity-bindings'
 import type {
   PaginationState,
   SortingState,
+  TableFeatures,
   Table_Internal,
+  Table_RowPagination,
+  Table_RowSorting,
 } from '../../../src'
 
 const features = {
@@ -20,7 +23,11 @@ const features = {
   rowSortingFeature,
 }
 
-function makeTable(options: any = {}) {
+function makeTable<TFeatures extends TableFeatures>(
+  options: any = {},
+): Table_Internal<TFeatures, any> &
+  Table_RowSorting<TFeatures, any> &
+  Table_RowPagination<TFeatures, any> {
   return constructTable({
     features: {
       ...coreFeatures,
@@ -30,7 +37,9 @@ function makeTable(options: any = {}) {
     columns: [],
     data: [],
     ...options,
-  }) as unknown as Table_Internal<typeof features, any>
+  }) as unknown as Table_Internal<TFeatures, any> &
+    Table_RowSorting<TFeatures, any> &
+    Table_RowPagination<TFeatures, any>
 }
 
 describe('three-layer atom architecture', () => {
diff --git a/packages/table-core/tests/unit/features/column-pinning/columnPinningFeature.utils.test.ts b/packages/table-core/tests/unit/features/column-pinning/columnPinningFeature.utils.test.ts
index db294ea042..e50fd05ebd 100644
--- a/packages/table-core/tests/unit/features/column-pinning/columnPinningFeature.utils.test.ts
+++ b/packages/table-core/tests/unit/features/column-pinning/columnPinningFeature.utils.test.ts
@@ -33,7 +33,14 @@ import {
   generateTestTableWithDataAndState,
 } from '../../../helpers/generateTestTable'
 import { getUpdaterResult } from '../../../helpers/testUtils'
-import type { Header } from '../../../../src'
+import type { Person } from '../../../fixtures/data/types'
+import type {
+  Header,
+  StockFeatures,
+  Table_ColumnOrdering,
+  Table_ColumnPinning,
+  Table_Internal,
+} from '../../../../src'
 
 describe('getDefaultColumnPinningState', () => {
   it('should return default column pinning state', () => {
@@ -550,7 +557,8 @@ describe('table_getPinnedLeafColumns', () => {
           right: [],
         },
       },
-    })
+    }) as Table_Internal<StockFeatures, Person> &
+      Table_ColumnPinning<StockFeatures, Person>
 
     const leafColumns = table_getPinnedLeafColumns(table, 'left')
 
@@ -644,7 +652,8 @@ describe('column pinning table instance APIs', () => {
           age: false,
         },
       },
-    })
+    }) as Table_Internal<StockFeatures, Person> &
+      Table_ColumnPinning<StockFeatures, Person>
 
     expect(
       table.getPinnedLeafColumns('left').map((col: { id: string }) => col.id),
@@ -673,7 +682,9 @@ describe('column pinning table instance APIs', () => {
   it('should update center visible columns when column order changes', () => {
     const table = generateTestTableWithDataAndState(1, {
       features: stockFeatures,
-    })
+    }) as Table_Internal<StockFeatures, Person> &
+      Table_ColumnPinning<StockFeatures, Person> &
+      Table_ColumnOrdering<StockFeatures, Person>
 
     expect(
       table.getCenterVisibleLeafColumns().map((col: { id: string }) => col.id),
diff --git a/packages/table-core/tests/unit/features/row-pinning/rowPinningFeature.utils.test.ts b/packages/table-core/tests/unit/features/row-pinning/rowPinningFeature.utils.test.ts
index bd1f3e039f..11d538c3cd 100644
--- a/packages/table-core/tests/unit/features/row-pinning/rowPinningFeature.utils.test.ts
+++ b/packages/table-core/tests/unit/features/row-pinning/rowPinningFeature.utils.test.ts
@@ -486,7 +486,7 @@ describe('row_pin', () => {
   it('should unpin a row when position is false', () => {
     const { table, onRowPinningChangeMock } =
       createTableWithMockOnPinningChange()
-    table.baseAtoms.rowPinning!.set({
+    table.baseAtoms.rowPinning.set({
       top: [ROW[0]],
       bottom: [],
     })
@@ -508,9 +508,7 @@ describe('row_pin', () => {
       createTableWithMockOnPinningChange()
     const row = table.getRow('0')
     const leafRows = [{ id: LEAF[1] }, { id: LEAF[2] }]
-    vi.spyOn(row, 'getLeafRows').mockReturnValue(
-      leafRows as unknown as Array<Row<TableFeatures, Person>>,
-    )
+    vi.spyOn(row, 'getLeafRows').mockReturnValue(leafRows as any)
 
     row_pin(row, 'top', true)
 
@@ -528,9 +526,7 @@ describe('row_pin', () => {
       createTableWithMockOnPinningChange()
     const row = table.getRow('0')
     const parentRows = [{ id: PARENT[1] }, { id: PARENT[2] }]
-    vi.spyOn(row, 'getParentRows').mockReturnValue(
-      parentRows as unknown as Array<Row<TableFeatures, Person>>,
-    )
+    vi.spyOn(row, 'getParentRows').mockReturnValue(parentRows as any)
 
     row_pin(row, 'top', false, true)
 
@@ -546,7 +542,7 @@ describe('row_pin', () => {
   it('should maintain existing pinned rows when pinning additional rows', () => {
     const { table, onRowPinningChangeMock } =
       createTableWithMockOnPinningChange()
-    table.baseAtoms.rowPinning!.set({
+    table.baseAtoms.rowPinning.set({
       top: [ROW[1]],
       bottom: [ROW[2]],
     })
@@ -569,7 +565,7 @@ describe('row_pin', () => {
   it('should remove row from other position when moving between top and bottom', () => {
     const { table, onRowPinningChangeMock } =
       createTableWithMockOnPinningChange()
-    table.baseAtoms.rowPinning!.set({
+    table.baseAtoms.rowPinning.set({
       top: [ROW[0]],
       bottom: [],
     })
diff --git a/skills/github-issue-repro-and-fix/SKILL.md b/skills/github-issue-repro-and-fix/SKILL.md
new file mode 100644
index 0000000000..00d6829125
--- /dev/null
+++ b/skills/github-issue-repro-and-fix/SKILL.md
@@ -0,0 +1,90 @@
+---
+name: github-issue-repro-and-fix
+description: >
+  Investigate a GitHub issue, determine whether it is a real bug, reproduce it
+  with the smallest practical test or example, and apply a focused fix only
+  after the failing behavior is confirmed. Use this when asked to look at,
+  verify, triage, reproduce, or fix a GitHub issue in this repository.
+---
+
+# GitHub Issue Repro And Fix
+
+Use this skill when the user provides a GitHub issue URL, issue number, copied
+issue body, or asks whether reported behavior is truly a bug before fixing it.
+
+## Workflow
+
+1. Gather the issue context.
+   - If given a URL or issue number, prefer `gh issue view <number> --json title,body,comments,labels,author,state,url`.
+   - If `gh` is unavailable or unauthenticated, use the GitHub web page or ask the user only when the issue content cannot be accessed.
+   - Read the issue comments, not just the opening report. Comments often contain maintainer guidance, reproductions, workarounds, duplicate links, and notes that the issue was fixed elsewhere.
+   - Capture the exact reported behavior, expected behavior, environment, reproduction steps, linked repro repository or sandbox, maintainer comments, and any user-confirmed workarounds.
+
+2. Look for related upstream context.
+   - Search repository issues, pull requests, and discussions for the issue number, mentioned APIs, error text, and reproduction keywords.
+   - Prefer GitHub search or `gh search issues`/`gh search prs` when available.
+   - Note related PRs, discussions, duplicate issues, regression reports, and changelog entries before deciding whether to patch.
+   - If a related PR already fixed the issue, verify whether the local workspace contains that change before editing.
+
+3. Map the report to the codebase.
+   - Identify the package, adapter, example, docs page, or shared core module involved.
+   - Search with `rg` for mentioned APIs, options, error text, test names, and related implementation files.
+   - Read the nearest tests before editing so the existing behavior contract is clear.
+
+4. Verify whether the reported behavior is real.
+   - Reproduce the bug locally before changing implementation when feasible.
+   - Prefer the smallest focused failing test over a full example app.
+   - If a UI or framework issue cannot be captured by a unit test, use the smallest existing example or fixture that exercises the behavior.
+   - Record the failing command and failure mode.
+   - If the issue cannot be reproduced, inspect whether it is already fixed, invalid usage, version-specific, or missing information.
+
+5. Decide whether a fix is the correct library direction.
+   - Separate "the reported behavior happens" from "the library should change."
+   - Check whether the request conflicts with documented concepts, API semantics, type contracts, backwards compatibility, or maintainer comments.
+   - Consider whether the better outcome is a code fix, documentation clarification, warning/error improvement, example update, or closing as intended behavior.
+   - When the issue raises a product/API semantics tradeoff, ask the user for a decision before implementing. Present concise pros and cons for each viable path.
+
+6. Apply a focused fix only when the direction is confirmed.
+   - Change the narrowest implementation surface that explains the confirmed failure.
+   - Preserve public APIs unless the issue explicitly concerns an intended API change.
+   - Follow existing local patterns for feature registration, state handling, adapter behavior, and test style.
+   - Avoid broad refactors, unrelated formatting churn, or opportunistic cleanup.
+
+7. Prove the fix.
+   - Run the previously failing test or reproduction first.
+   - Run the nearest relevant package test, typecheck, or lint command if available and proportionate.
+   - If a regression test was possible, commit the failing scenario as part of the change.
+   - If no automated test was practical, document the manual verification steps and remaining risk.
+
+8. Report the outcome.
+   - State whether the GitHub report is a confirmed bug, duplicate/already fixed, unsupported usage, documentation gap, or inconclusive.
+   - If the behavior is real but not a bug, say that explicitly and explain the library contract that makes it intended behavior.
+   - Summarize the root cause and fix in concrete terms.
+   - Include the exact verification commands and results.
+   - Call out any test gaps or conditions that could not be reproduced.
+
+## Decision Rules
+
+- Do not patch first and infer the bug later. Establish a failing observation before editing whenever the repo makes that practical.
+- Do not assume a confirmed reproduction means the requested change is desirable. Validate the request against the library's design model before fixing.
+- Treat linked reproductions as evidence, not as proof. Reduce them to a local test or minimal local reproduction before changing shared code.
+- If the issue is caused by misuse but the API makes the misuse easy, consider a docs update, runtime warning, or clearer type error only if it fits existing project conventions.
+- If the report depends on old package versions, compare against the current workspace behavior and say clearly which version was tested.
+- If the issue spans multiple framework adapters, fix shared core behavior first when the root cause is framework-agnostic; otherwise keep adapter-specific changes isolated.
+- Do not run `git` commands, create commits, push branches, or open pull requests. Leave all git and PR operations to the user.
+
+## Useful Commands
+
+```sh
+gh issue view <number> --json title,body,comments,labels,author,state,url
+gh search issues "<query>" --repo TanStack/table
+gh search prs "<query>" --repo TanStack/table
+rg "<api-or-error-text>"
+pnpm test
+pnpm typecheck
+pnpm lint
+```
+
+Prefer package-specific commands from `package.json` when they exist. Use the
+smallest command that validates the touched behavior before running broader
+checks.