feat(seer): Add LLM context to widget builder page

Register a 'widget-builder' node in the LLM context tree so the Seer
Explorer agent understands what widget the user is configuring. Pushes
builder state (dataset, displayType, visualize, fields, query, sort,
thresholds, legendAlias) with readable condition transforms.

Also adds the widget builder routes to STRUCTURED_CONTEXT_ROUTES so
structured context is sent instead of ASCII when the builder is open.

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

Author: Mihir-Mavalankar

static/app/views/dashboards/widgetBuilder/components/newWidgetBuilder.spec.tsx

@@ -8,7 +8,13 @@ import {PageFiltersContainer} from 'sentry/components/pageFilters/container';
 import {PageFiltersStore} from 'sentry/components/pageFilters/store';
 import {OrganizationStore} from 'sentry/stores/organizationStore';
 import {ProjectsStore} from 'sentry/stores/projectsStore';
+import {DisplayType, WidgetType} from 'sentry/views/dashboards/types';
 import {WidgetBuilderV2} from 'sentry/views/dashboards/widgetBuilder/components/newWidgetBuilder';
+import {
+  LLMContextProvider,
+  useLLMContext,
+} from 'sentry/views/seerExplorer/contexts/llmContext';
+import type {LLMContextSnapshot} from 'sentry/views/seerExplorer/contexts/llmContextTypes';
 
 const organization = OrganizationFixture({
   features: ['open-membership', 'visibility-explore-view'],
@@ -294,4 +300,92 @@ describe('NewWidgetBuilder', () => {
 
     expect(await screen.findByText('Select a widget to preview')).toBeInTheDocument();
   });
+
+  it('populates LLM context with builder state', async () => {
+    const {ContextCapture, getSnapshot} = makeContextCapture();
+
+    render(
+      <LLMContextProvider>
+        <ContextCapture />
+        <WidgetBuilderV2
+          isOpen
+          onClose={onCloseMock}
+          onSave={onSaveMock}
+          dashboard={DashboardFixture([])}
+          dashboardFilters={{}}
+          openWidgetTemplates={false}
+          setOpenWidgetTemplates={jest.fn()}
+        />
+      </LLMContextProvider>,
+      {
+        organization,
+        initialRouterConfig: {
+          location: {
+            pathname: '/organizations/org-slug/dashboard/1/widget-builder/widget/new/',
+            query: {
+              displayType: DisplayType.LINE,
+              dataset: WidgetType.ERRORS,
+              title: 'My Widget',
+              yAxis: 'count()',
+              field: 'browser.name',
+              query: 'browser.name:Firefox',
+            },
+          },
+        },
+      }
+    );
+
+    await waitFor(() => {
+      const node = getSnapshot().nodes.find(n => n.nodeType === 'widget-builder');
+      expect(node).toBeDefined();
+    });
+
+    const node = getSnapshot().nodes.find(n => n.nodeType === 'widget-builder')!;
+    const data = node.data as Record<string, unknown>;
+    expect(data.mode).toBe('creating');
+    expect(data.title).toBe('My Widget');
+    expect(data.dataset).toBe(WidgetType.ERRORS);
+    expect(data.displayType).toBe(DisplayType.LINE);
+    expect(data.visualize).toEqual(['count()']);
+    expect(data.fields).toEqual(['browser.name']);
+    expect(data.query).toEqual(['browser.name:Firefox']);
+  });
+
+  it('does not register LLM context when the builder is closed', () => {
+    const {ContextCapture, getSnapshot} = makeContextCapture();
+
+    render(
+      <LLMContextProvider>
+        <ContextCapture />
+        <WidgetBuilderV2
+          isOpen={false}
+          onClose={onCloseMock}
+          onSave={onSaveMock}
+          dashboard={DashboardFixture([])}
+          dashboardFilters={{}}
+          openWidgetTemplates={false}
+          setOpenWidgetTemplates={jest.fn()}
+        />
+      </LLMContextProvider>
+    );
+
+    const node = getSnapshot().nodes.find(n => n.nodeType === 'widget-builder');
+    expect(node).toBeUndefined();
+  });
 });
+
+function makeContextCapture() {
+  const ref: {current: (() => LLMContextSnapshot) | null} = {current: null};
+  function ContextCapture() {
+    const {getLLMContext} = useLLMContext();
+    ref.current = getLLMContext;
+    return null;
+  }
+  return {
+    ContextCapture,
+    getSnapshot: () => {
+      if (!ref.current) throw new Error('ContextCapture not mounted');
+      return ref.current();
+    },
+  };
+}

static/app/views/dashboards/widgetBuilder/components/widgetBuilderSlideout.tsx

@@ -26,6 +26,7 @@ import {IconClose} from 'sentry/icons';
 import {t, tctCode} from 'sentry/locale';
 import {trackAnalytics} from 'sentry/utils/analytics';
 import {WidgetBuilderVersion} from 'sentry/utils/analytics/dashboardsAnalyticsEvents';
+import {generateFieldAsString} from 'sentry/utils/discover/fields';
 import {useLocation} from 'sentry/utils/useLocation';
 import {useMedia} from 'sentry/utils/useMedia';
 import {useOrganization} from 'sentry/utils/useOrganization';
@@ -70,7 +71,10 @@ import {useSegmentSpanWidgetState} from 'sentry/views/dashboards/widgetBuilder/h
 import {convertBuilderStateToWidget} from 'sentry/views/dashboards/widgetBuilder/utils/convertBuilderStateToWidget';
 import {convertWidgetToBuilderState} from 'sentry/views/dashboards/widgetBuilder/utils/convertWidgetToBuilderStateParams';
 import type {OnDataFetchedParams} from 'sentry/views/dashboards/widgetCard';
+import {readableConditions} from 'sentry/views/dashboards/widgetCard/widgetLLMContext';
 import {getTopNConvertedDefaultWidgets} from 'sentry/views/dashboards/widgetLibrary/data';
+import {useLLMContext} from 'sentry/views/seerExplorer/contexts/llmContext';
+import {registerLLMContext} from 'sentry/views/seerExplorer/contexts/registerLLMContext';
 
 type WidgetBuilderSlideoutProps = {
   dashboard: DashboardDetails;
@@ -86,7 +90,7 @@ type WidgetBuilderSlideoutProps = {
   thresholdMetaState?: ThresholdMetaState;
 };
 
-export function WidgetBuilderSlideout({
+function WidgetBuilderSlideoutInner({
   onClose,
   onSave,
   onQueryConditionChange,
@@ -108,6 +112,23 @@ export function WidgetBuilderSlideout({
   const [error, setError] = useState<Record<string, any>>({});
   const theme = useTheme();
   const isEditing = useIsEditingWidget();
+
+  // Push widget builder state into the LLM context tree for Seer Explorer.
+  useLLMContext({
+    contextHint:
+      'Sentry widget builder. The user is configuring a dashboard widget. visualize is the y-axis metrics (timeseries) or the aggregate (big number/table). fields are group-by columns (timeseries) or visible columns (table). query filters the data and sort controls ordering.',
+    mode: isEditing ? 'editing' : 'creating',
+    title: state.title,
+    description: state.description,
+    dataset: state.dataset,
+    displayType: state.displayType,
+    visualize: state.yAxis?.map(generateFieldAsString),
+    fields: state.fields?.map(generateFieldAsString),
+    query: state.query?.map(readableConditions),
+    sort: state.sort?.map(s => (s.kind === 'desc' ? `-${s.field}` : s.field)),
+    thresholds: state.thresholds,
+    legendAlias: state.legendAlias,
+  });
   const source = useDashboardWidgetSource();
   const {cacheBuilderState} = useCacheBuilderState();
   const {setSegmentSpanBuilderState} = useSegmentSpanWidgetState();
@@ -508,6 +529,11 @@ export function WidgetBuilderSlideout({
   );
 }
 
+export const WidgetBuilderSlideout = registerLLMContext(
+  'widget-builder',
+  WidgetBuilderSlideoutInner
+);
+
 function Section({children}: {children: React.ReactNode}) {
   return (
     <SectionWrapper>

static/app/views/seerExplorer/contexts/llmContextTypes.ts

@@ -17,7 +17,7 @@
  * Known node types for the LLM context tree.
  * Add new types here as new context-aware components are registered.
  */
-export type LLMContextNodeType = 'chart' | 'dashboard' | 'widget';
+export type LLMContextNodeType = 'chart' | 'dashboard' | 'widget' | 'widget-builder';
 
 /**
  * A single node in the flat registry.

static/app/views/seerExplorer/hooks/useSeerExplorer.tsx

@@ -52,7 +52,11 @@ type SeerExplorerChatResponse = {
 const POLL_INTERVAL = 500; // Poll every 500ms
 
 /** Routes where the LLMContext tree provides structured page context. */
-const STRUCTURED_CONTEXT_ROUTES = new Set(['/dashboard/:dashboardId/']);
+const STRUCTURED_CONTEXT_ROUTES = new Set([
+  '/dashboard/:dashboardId/',
+  '/dashboard/:dashboardId/widget-builder/widget/new/',
+  '/dashboard/:dashboardId/widget-builder/widget/:widgetIndex/edit/',
+]);
 
 const OPTIMISTIC_ASSISTANT_TEXTS = [
   'Looking around...',