refactor(mcp): extract _add_xy_limits helper and move series_limit tests

Extract row/series limit assignment into a private helper to keep
map_xy_config within the McCabe complexity threshold, removing the
noqa: C901 suppression. Move series_limit schema tests out of
TestRowLimit and into a dedicated TestSeriesLimit class.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

superset-frontend/src/SqlLab/actions/sqlLab.ts

@@ -1671,7 +1671,7 @@ export interface VizOptions {
 
 export function createDatasource(
   vizOptions: VizOptions,
-): SqlLabThunkAction<Promise<unknown>> {
+): SqlLabThunkAction<Promise<{ id: number }>> {
   return (dispatch: AppDispatch) => {
     dispatch(createDatasourceStarted());
     const { dbId, catalog, schema, datasourceName, sql, templateParams } =
@@ -1691,9 +1691,10 @@ export function createDatasource(
       }),
     })
       .then(({ json }) => {
-        dispatch(createDatasourceSuccess(json as { id: number }));
+        const result = json as { id: number };
+        dispatch(createDatasourceSuccess(result));
 
-        return Promise.resolve(json);
+        return result;
       })
       .catch(error => {
         getClientErrorObject(error).then(e => {

superset-frontend/src/SqlLab/components/SaveDatasetModal/SaveDatasetModal.test.tsx

@@ -16,8 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import * as reactRedux from 'react-redux';
-import { act } from 'react';
+import { act, type ComponentProps } from 'react';
 import {
   cleanup,
   fireEvent,
@@ -40,6 +39,19 @@ const mockedProps = {
   datasource: testQuery,
 };
 
+// Render with the SqlLab user fixture preloaded into the mock store so the
+// component's useSelector(state => state.user) returns a useful value.
+// Previously this test used jest.spyOn(reactRedux, 'useSelector') to inject
+// the user directly, which can't intercept calls routed through the typed
+// useAppSelector hook.
+const renderModal = (
+  props: Partial<ComponentProps<typeof SaveDatasetModal>> = {},
+) =>
+  render(<SaveDatasetModal {...mockedProps} {...props} />, {
+    useRedux: true,
+    initialState: { user },
+  });
+
 fetchMock.get('glob:*/api/v1/dataset/?*', {
   result: mockdatasets,
   dataset_count: 3,
@@ -47,17 +59,17 @@ fetchMock.get('glob:*/api/v1/dataset/?*', {
 
 jest.useFakeTimers({ advanceTimers: true });
 
-// Mock the user
-const useSelectorMock = jest.spyOn(reactRedux, 'useSelector');
 beforeEach(() => {
-  useSelectorMock.mockClear();
   cleanup();
 });
 
-// Mock the createDatasource action
-const useDispatchMock = jest.spyOn(reactRedux, 'useDispatch');
+// Mock createDatasource to return a thunk that resolves with the dataset's
+// new id. The test's mock store includes redux-thunk middleware (from RTK's
+// getDefaultMiddleware), so dispatch(createDatasource(...)) properly unwraps
+// the thunk and the production code's .then((data) => clearDatasetCache(data.id))
+// chain receives `{ id: 123 }`. Individual tests can override per-call as needed.
 jest.mock('src/SqlLab/actions/sqlLab', () => ({
-  createDatasource: jest.fn(),
+  createDatasource: jest.fn(() => () => Promise.resolve({ id: 123 })),
 }));
 jest.mock('src/explore/exploreUtils/formData', () => ({
   postFormData: jest.fn(),
@@ -70,7 +82,7 @@ jest.mock('src/utils/cachedSupersetGet', () => ({
 // eslint-disable-next-line no-restricted-globals -- TODO: Migrate from describe blocks
 describe('SaveDatasetModal', () => {
   test('renders a "Save as new" field', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     const saveRadioBtn = screen.getByRole('radio', {
       name: /save as new/i,
@@ -87,7 +99,7 @@ describe('SaveDatasetModal', () => {
   });
 
   test('renders an "Overwrite existing" field', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     const overwriteRadioBtn = screen.getByRole('radio', {
       name: /overwrite existing/i,
@@ -103,20 +115,20 @@ describe('SaveDatasetModal', () => {
   });
 
   test('renders a close button', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     expect(screen.getByRole('button', { name: /close/i })).toBeInTheDocument();
   });
 
   test('renders a save button when "Save as new" is selected', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     // "Save as new" is selected when the modal opens by default
     expect(screen.getByRole('button', { name: /save/i })).toBeInTheDocument();
   });
 
   test('renders an overwrite button when "Overwrite existing" is selected', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     // Click the overwrite radio button to reveal the overwrite confirmation and back buttons
     const overwriteRadioBtn = screen.getByRole('radio', {
@@ -130,8 +142,7 @@ describe('SaveDatasetModal', () => {
   });
 
   test('renders the overwrite button as disabled until an existing dataset is selected', async () => {
-    useSelectorMock.mockReturnValue({ ...user });
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     // Click the overwrite radio button
     const overwriteRadioBtn = screen.getByRole('radio', {
@@ -168,8 +179,7 @@ describe('SaveDatasetModal', () => {
   });
 
   test('renders a confirm overwrite screen when overwrite is clicked', async () => {
-    useSelectorMock.mockReturnValue({ ...user });
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     // Click the overwrite radio button
     const overwriteRadioBtn = screen.getByRole('radio', {
@@ -215,11 +225,7 @@ describe('SaveDatasetModal', () => {
   });
 
   test('sends the schema when creating the dataset', async () => {
-    const dummyDispatch = jest.fn().mockResolvedValue({});
-    useDispatchMock.mockReturnValue(dummyDispatch);
-    useSelectorMock.mockReturnValue({ ...user });
-
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     const inputFieldText = screen.getByDisplayValue(/unimportant/i);
     fireEvent.change(inputFieldText, { target: { value: 'my dataset' } });
@@ -240,17 +246,9 @@ describe('SaveDatasetModal', () => {
   });
 
   test('sends the catalog when creating the dataset', async () => {
-    const dummyDispatch = jest.fn().mockResolvedValue({});
-    useDispatchMock.mockReturnValue(dummyDispatch);
-    useSelectorMock.mockReturnValue({ ...user });
-
-    render(
-      <SaveDatasetModal
-        {...mockedProps}
-        datasource={{ ...mockedProps.datasource, catalog: 'public' }}
-      />,
-      { useRedux: true },
-    );
+    renderModal({
+      datasource: { ...mockedProps.datasource, catalog: 'public' },
+    });
 
     const inputFieldText = screen.getByDisplayValue(/unimportant/i);
     fireEvent.change(inputFieldText, { target: { value: 'my dataset' } });
@@ -271,7 +269,7 @@ describe('SaveDatasetModal', () => {
   });
 
   test('does not renders a checkbox button when template processing is disabled', () => {
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
     expect(screen.queryByRole('checkbox')).not.toBeInTheDocument();
   });
 
@@ -280,7 +278,7 @@ describe('SaveDatasetModal', () => {
     global.featureFlags = {
       [FeatureFlag.EnableTemplateProcessing]: true,
     };
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
     expect(screen.getByRole('checkbox')).toBeInTheDocument();
   });
 
@@ -289,15 +287,11 @@ describe('SaveDatasetModal', () => {
     global.featureFlags = {
       [FeatureFlag.EnableTemplateProcessing]: true,
     };
-    const propsWithTemplateParam = {
-      ...mockedProps,
+    renderModal({
       datasource: {
         ...testQuery,
         templateParams: JSON.stringify({ my_param: 12 }),
       },
-    };
-    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
-      useRedux: true,
     });
     const inputFieldText = screen.getByDisplayValue(/unimportant/i);
     fireEvent.change(inputFieldText, { target: { value: 'my dataset' } });
@@ -324,15 +318,11 @@ describe('SaveDatasetModal', () => {
     global.featureFlags = {
       [FeatureFlag.EnableTemplateProcessing]: true,
     };
-    const propsWithTemplateParam = {
-      ...mockedProps,
+    renderModal({
       datasource: {
         ...testQuery,
         templateParams: JSON.stringify({ my_param: 12 }),
       },
-    };
-    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
-      useRedux: true,
     });
     const inputFieldText = screen.getByDisplayValue(/unimportant/i);
     fireEvent.change(inputFieldText, { target: { value: 'my dataset' } });
@@ -393,19 +383,11 @@ describe('SaveDatasetModal', () => {
       .spyOn(SupersetClient, 'put')
       .mockResolvedValue({ json: { result: { id: 0 } } } as any);
 
-    const dummyDispatch = jest.fn().mockResolvedValue({});
-    useDispatchMock.mockReturnValue(dummyDispatch);
-    useSelectorMock.mockReturnValue({ ...user });
-
-    const propsWithTemplateParam = {
-      ...mockedProps,
+    renderModal({
       datasource: {
         ...testQuery,
         templateParams: JSON.stringify({ my_param: 12, _filters: 'foo' }),
       },
-    };
-    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
-      useRedux: true,
     });
 
     // Check the "Include Template Parameters" checkbox
@@ -443,19 +425,11 @@ describe('SaveDatasetModal', () => {
       .spyOn(SupersetClient, 'put')
       .mockResolvedValue({ json: { result: { id: 0 } } } as any);
 
-    const dummyDispatch = jest.fn().mockResolvedValue({});
-    useDispatchMock.mockReturnValue(dummyDispatch);
-    useSelectorMock.mockReturnValue({ ...user });
-
-    const propsWithTemplateParam = {
-      ...mockedProps,
+    renderModal({
       datasource: {
         ...testQuery,
         templateParams: JSON.stringify({ my_param: 12 }),
       },
-    };
-    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
-      useRedux: true,
     });
 
     // Do NOT check the "Include Template Parameters" checkbox
@@ -489,12 +463,9 @@ describe('SaveDatasetModal', () => {
       'postFormData',
     );
 
-    const dummyDispatch = jest.fn().mockResolvedValue({ id: 123 });
-    useDispatchMock.mockReturnValue(dummyDispatch);
-    useSelectorMock.mockReturnValue({ ...user });
     postFormData.mockResolvedValue('chart_key_123');
 
-    render(<SaveDatasetModal {...mockedProps} />, { useRedux: true });
+    renderModal();
 
     const inputFieldText = screen.getByDisplayValue(/unimportant/i);
     fireEvent.change(inputFieldText, { target: { value: 'my dataset' } });

superset-frontend/src/SqlLab/components/SaveDatasetModal/index.tsx

@@ -34,7 +34,6 @@ import { t } from '@apache-superset/core/translation';
 import {
   SupersetClient,
   JsonResponse,
-  JsonObject,
   QueryResponse,
   QueryFormData,
   VizType,
@@ -44,16 +43,14 @@ import {
 } from '@superset-ui/core';
 import { styled } from '@apache-superset/core/theme';
 import { extendedDayjs as dayjs } from '@superset-ui/core/utils/dates';
-import { useSelector, useDispatch } from 'react-redux';
+import { useAppDispatch, useAppSelector } from 'src/views/store';
 import rison from 'rison';
 import { createDatasource } from 'src/SqlLab/actions/sqlLab';
 import { addDangerToast } from 'src/components/MessageToasts/actions';
-import { UserWithPermissionsAndRoles as User } from 'src/types/bootstrapTypes';
 import {
   DatasetRadioState,
   EXPLORE_CHART_DEFAULT,
   DatasetOwner,
-  SqlLabRootState,
 } from 'src/SqlLab/types';
 import { mountExploreUrl } from 'src/explore/exploreUtils';
 import { postFormData } from 'src/explore/exploreUtils/formData';
@@ -221,7 +218,7 @@ export const SaveDatasetModal = ({
   openWindow = true,
   formData = {},
 }: SaveDatasetModalProps) => {
-  const defaultVizType = useSelector<SqlLabRootState, string>(
+  const defaultVizType = useAppSelector(
     state => state.common?.conf?.DEFAULT_VIZ_TYPE || VizType.Table,
   );
 
@@ -240,8 +237,8 @@ export const SaveDatasetModal = ({
   >(undefined);
   const [loading, setLoading] = useState<boolean>(false);
 
-  const user = useSelector<SqlLabRootState, User>(state => state.user);
-  const dispatch = useDispatch<(dispatch: any) => Promise<JsonObject>>();
+  const user = useAppSelector(state => state.user);
+  const dispatch = useAppDispatch();
   const [includeTemplateParameters, setIncludeTemplateParameters] =
     useState(false);
 

superset-frontend/src/components/ListView/Filters/Select.test.tsx

@@ -0,0 +1,267 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { createRef } from 'react';
+import {
+  render,
+  screen,
+  selectOption,
+  waitFor,
+} from 'spec/helpers/testing-library';
+import { ListViewFilterOperator } from '../types';
+import UIFilters from './index';
+import SelectFilter from './Select';
+import type { FilterHandler } from './types';
+
+const mockUpdateFilterValue = jest.fn();
+
+beforeEach(() => {
+  mockUpdateFilterValue.mockClear();
+});
+
+test('select filter with ReactNode label uses option title when serializing selection', async () => {
+  // Regression for sc-104554: the chart-list Owner filter renders options
+  // with ReactNode labels (name + email). The value passed to
+  // updateFilterValue is serialized into URL / filter state and re-used to
+  // render the filter pill on return. It must carry the plain-text name
+  // (from `title`) and not fall back to the numeric user id.
+  const ReactNodeLabel = (
+    <div>
+      <span>John Doe</span>
+      <span>john@example.com</span>
+    </div>
+  );
+
+  const fetchSelects = jest.fn().mockResolvedValue({
+    data: [
+      {
+        label: ReactNodeLabel,
+        value: 42,
+        title: 'John Doe',
+      },
+    ],
+    totalCount: 1,
+  });
+
+  const filters = [
+    {
+      Header: 'Owner',
+      key: 'owner',
+      id: 'owners',
+      input: 'select' as const,
+      operator: ListViewFilterOperator.RelationManyMany,
+      unfilteredLabel: 'All',
+      fetchSelects,
+      paginate: true,
+    },
+  ];
+
+  render(
+    <UIFilters
+      filters={filters}
+      internalFilters={[]}
+      updateFilterValue={mockUpdateFilterValue}
+    />,
+  );
+
+  await selectOption('John Doe', 'Owner');
+
+  await waitFor(() => {
+    expect(mockUpdateFilterValue).toHaveBeenCalledWith(0, {
+      label: 'John Doe',
+      value: 42,
+    });
+  });
+});
+
+test('select filter falls back to stringified value when no string label or title is available', async () => {
+  const fetchSelects = jest.fn().mockResolvedValue({
+    data: [
+      {
+        label: <span>123</span>,
+        value: 123,
+      },
+    ],
+    totalCount: 1,
+  });
+
+  const filters = [
+    {
+      Header: 'Something',
+      key: 'something',
+      id: 'something',
+      input: 'select' as const,
+      operator: ListViewFilterOperator.RelationOneMany,
+      unfilteredLabel: 'All',
+      fetchSelects,
+    },
+  ];
+
+  render(
+    <UIFilters
+      filters={filters}
+      internalFilters={[]}
+      updateFilterValue={mockUpdateFilterValue}
+    />,
+  );
+
+  await selectOption('123', 'Something');
+
+  await waitFor(() => {
+    expect(mockUpdateFilterValue).toHaveBeenCalledWith(0, {
+      label: '123',
+      value: 123,
+    });
+  });
+});
+
+test('plain select with string label passes label through unchanged', async () => {
+  // Happy-path coverage for the typeof-string branch in onChange, exercised
+  // through the non-async Select wrapper (selects array, no fetchSelects).
+  const filters = [
+    {
+      Header: 'Status',
+      key: 'status',
+      id: 'status',
+      input: 'select' as const,
+      operator: ListViewFilterOperator.Equals,
+      unfilteredLabel: 'All',
+      selects: [
+        { label: 'Published', value: 7 },
+        { label: 'Draft', value: 8 },
+      ],
+    },
+  ];
+
+  render(
+    <UIFilters
+      filters={filters}
+      internalFilters={[]}
+      updateFilterValue={mockUpdateFilterValue}
+    />,
+  );
+
+  await selectOption('Published', 'Status');
+
+  await waitFor(() => {
+    expect(mockUpdateFilterValue).toHaveBeenCalledWith(0, {
+      label: 'Published',
+      value: 7,
+    });
+  });
+});
+
+test('plain select with ReactNode label uses option title when serializing selection', async () => {
+  // Parallel coverage to the AsyncSelect ReactNode-with-title test, against
+  // the non-async Select wrapper. Guards against the two wrappers ever
+  // diverging on antd's two-arg onChange shape.
+  const ReactNodeLabel = (
+    <div>
+      <span>Jane Roe</span>
+      <span>jane@example.com</span>
+    </div>
+  );
+
+  const filters = [
+    {
+      Header: 'Owner',
+      key: 'owner',
+      id: 'owners',
+      input: 'select' as const,
+      operator: ListViewFilterOperator.RelationManyMany,
+      unfilteredLabel: 'All',
+      selects: [{ label: ReactNodeLabel, value: 99, title: 'Jane Roe' }],
+    },
+  ];
+
+  render(
+    <UIFilters
+      filters={filters}
+      internalFilters={[]}
+      updateFilterValue={mockUpdateFilterValue}
+    />,
+  );
+
+  await selectOption('Jane Roe', 'Owner');
+
+  await waitFor(() => {
+    expect(mockUpdateFilterValue).toHaveBeenCalledWith(0, {
+      label: 'Jane Roe',
+      value: 99,
+    });
+  });
+});
+
+test('clearFilter notifies onSelect with undefined and isClear=true', () => {
+  // The isClear flag is what allows the parent (Filters/index) to suppress
+  // onFilterUpdate side-effects when the user clears the filter rather than
+  // picking a new value. Lock that contract in.
+  const mockOnSelect = jest.fn();
+  const ref = createRef<FilterHandler>();
+
+  render(
+    <SelectFilter
+      Header="Owner"
+      initialValue={{ label: 'John Doe', value: 42 }}
+      onSelect={mockOnSelect}
+      selects={[{ label: 'John Doe', value: 42, title: 'John Doe' }]}
+      ref={ref}
+    />,
+  );
+
+  ref.current?.clearFilter();
+
+  expect(mockOnSelect).toHaveBeenCalledWith(undefined, true);
+});
+
+test('rehydrates filter pill from initialValue with plain-string label', async () => {
+  // The user-visible regression: after URL/state rehydration the filter pill
+  // must render the human-readable name, not the numeric user id. The fix
+  // ensures the persisted label is a string; this test asserts that string
+  // is what surfaces in the rendered combobox selection.
+  const filters = [
+    {
+      Header: 'Owner',
+      key: 'owner',
+      id: 'owners',
+      input: 'select' as const,
+      operator: ListViewFilterOperator.RelationManyMany,
+      unfilteredLabel: 'All',
+      fetchSelects: jest.fn().mockResolvedValue({ data: [], totalCount: 0 }),
+      paginate: true,
+    },
+  ];
+
+  render(
+    <UIFilters
+      filters={filters}
+      internalFilters={[
+        {
+          id: 'owners',
+          operator: ListViewFilterOperator.RelationManyMany,
+          value: { label: 'John Doe', value: 42 },
+        },
+      ]}
+      updateFilterValue={mockUpdateFilterValue}
+    />,
+  );
+
+  await waitFor(() => {
+    expect(screen.getByText('John Doe')).toBeInTheDocument();
+  });
+});

superset-frontend/src/components/ListView/Filters/Select.tsx

@@ -58,14 +58,22 @@ function SelectFilter(
 ) {
   const [selectedOption, setSelectedOption] = useState(initialValue);
 
-  const onChange = (selected: SelectOption) => {
+  const onChange = (selected: SelectOption, option?: SelectOption) => {
+    // antd's `onChange` (with `labelInValue`) passes the `{label, value}`
+    // labeled-value as the first arg and the full option (which carries
+    // `title` and any other fields) as the second. Options may supply a
+    // ReactNode label (e.g. OwnerSelectLabel for the chart list Owner
+    // filter). Since this object is serialized into the URL and rehydrated
+    // as the filter pill on return, we need a plain string. Prefer `title`
+    // (set by callers to the human-readable name) before falling back to
+    // the value.
     onSelect(
       selected
         ? {
             label:
               typeof selected.label === 'string'
                 ? selected.label
-                : String(selected.value),
+                : (option?.title ?? String(selected.value)),
             value: selected.value,
           }
         : undefined,

superset-frontend/src/components/ListView/types.ts

@@ -26,6 +26,10 @@ export interface SortColumn {
 export interface SelectOption {
   label: ReactNode;
   value: any;
+  // Plain-text representation of the option. Callers should set this when
+  // `label` is a ReactNode so that the option can be serialized (e.g. into
+  // URL filter state) without losing the human-readable name.
+  title?: string;
   [key: string]: unknown;
 }
 

superset/mcp_service/chart/chart_utils.py

@@ -648,6 +648,12 @@ def _resolve_default_x_axis(
     return config.model_copy(update={"x": ColumnRef(name=dataset.main_dttm_col)})
 
 
+def _add_xy_limits(form_data: Dict[str, Any], config: XYChartConfig) -> None:
+    form_data["row_limit"] = config.row_limit
+    if config.series_limit is not None:
+        form_data["series_limit"] = config.series_limit
+
+
 def map_xy_config(
     config: XYChartConfig, dataset_id: int | str | None = None
 ) -> Dict[str, Any]:
@@ -712,7 +718,7 @@ def map_xy_config(
     if x_is_temporal:
         _ensure_temporal_adhoc_filter(form_data, config.x.name)
 
-    form_data["row_limit"] = config.row_limit
+    _add_xy_limits(form_data, config)
 
     # Add stacking configuration
     if getattr(config, "stacked", False):

superset/mcp_service/chart/schemas.py

@@ -1304,6 +1304,16 @@ class XYChartConfig(UnknownFieldCheckMixin):
         "Do NOT use adhoc_filters or raw SQL expressions.",
     )
     row_limit: int = Field(10000, description="Max data points", ge=1, le=50000)
+    series_limit: int | None = Field(
+        None,
+        description=(
+            "Max number of series to show when group_by is set. "
+            "Limits the distinct values rendered as separate lines/bars. "
+            "Only applies when group_by is specified."
+        ),
+        ge=1,
+        le=10000,
+    )
 
     @field_validator("group_by", mode="before")
     @classmethod

tests/unit_tests/mcp_service/chart/test_chart_schemas.py

@@ -485,6 +485,47 @@ class TestRowLimit:
             )
 
 
+class TestSeriesLimit:
+    """Test series_limit field on XYChartConfig."""
+
+    def test_xy_chart_series_limit_default_none(self) -> None:
+        """Test that XYChartConfig series_limit defaults to None."""
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="date"),
+            y=[ColumnRef(name="revenue", aggregate="SUM")],
+        )
+        assert config.series_limit is None
+
+    def test_xy_chart_series_limit_custom(self) -> None:
+        """Test that XYChartConfig accepts a custom series_limit."""
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="date"),
+            y=[ColumnRef(name="revenue", aggregate="SUM")],
+            group_by=[ColumnRef(name="region")],
+            series_limit=5,
+        )
+        assert config.series_limit == 5
+
+    def test_xy_chart_series_limit_validation(self) -> None:
+        """Test that XYChartConfig rejects invalid series_limit values."""
+        with pytest.raises(ValidationError):
+            XYChartConfig(
+                chart_type="xy",
+                x=ColumnRef(name="date"),
+                y=[ColumnRef(name="revenue", aggregate="SUM")],
+                series_limit=0,
+            )
+        with pytest.raises(ValidationError):
+            XYChartConfig(
+                chart_type="xy",
+                x=ColumnRef(name="date"),
+                y=[ColumnRef(name="revenue", aggregate="SUM")],
+                series_limit=10001,
+            )
+
+
 class TestTableChartConfigExtraFields:
     """Test TableChartConfig rejects unknown fields."""
 

tests/unit_tests/mcp_service/chart/test_chart_utils.py

@@ -804,6 +804,38 @@ class TestMapXYConfig:
 
         assert result["row_limit"] == 10000
 
+    @patch("superset.mcp_service.chart.chart_utils.is_column_truly_temporal")
+    def test_map_xy_config_series_limit(self, mock_is_temporal) -> None:
+        """Test that series_limit is mapped to form_data when set."""
+        mock_is_temporal.return_value = True
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="date"),
+            y=[ColumnRef(name="revenue", aggregate="SUM")],
+            kind="line",
+            group_by=[ColumnRef(name="region")],
+            series_limit=10,
+        )
+
+        result = map_xy_config(config)
+
+        assert result["series_limit"] == 10
+
+    @patch("superset.mcp_service.chart.chart_utils.is_column_truly_temporal")
+    def test_map_xy_config_no_series_limit_by_default(self, mock_is_temporal) -> None:
+        """Test that series_limit is omitted from form_data when not set."""
+        mock_is_temporal.return_value = True
+        config = XYChartConfig(
+            chart_type="xy",
+            x=ColumnRef(name="date"),
+            y=[ColumnRef(name="revenue", aggregate="SUM")],
+            kind="line",
+        )
+
+        result = map_xy_config(config)
+
+        assert "series_limit" not in result
+
     @patch("superset.mcp_service.chart.chart_utils.is_column_truly_temporal")
     def test_map_xy_config_saved_metric(self, mock_is_temporal: Any) -> None:
         """Test XY config with saved metric emits string in metrics list"""