default state of data sources side panel is open

frontends/ui/src/features/layout/components/MainLayout.spec.tsx

@@ -13,7 +13,7 @@ const mockStartNewSessionDraft = vi.fn()
 const mockDeleteConversation = vi.fn()
 const mockDeleteAllConversations = vi.fn()
 const mockUpdateConversationTitle = vi.fn()
-const mockCloseRightPanel = vi.fn()
+const mockOpenRightPanel = vi.fn()
 
 // Mock the useSessionUrl hook (uses Next.js App Router hooks)
 vi.mock('@/hooks/use-session-url', () => ({
@@ -54,7 +54,7 @@ vi.mock('../store', () => ({
     isSessionsPanelOpen: false,
     setSessionsPanelOpen: vi.fn(),
     enabledDataSourceIds: ['source-1', 'source-2'],
-    closeRightPanel: mockCloseRightPanel,
+    openRightPanel: mockOpenRightPanel,
   })),
 }))
 
@@ -151,7 +151,7 @@ describe('MainLayout', () => {
   test('passes auth state to components', () => {
     const onSignIn = vi.fn()
     const onSignOut = vi.fn()
-    const user = { name: 'Test User', email: 'test@example.com' }
+    const user = { name: 'Test User', email: 'test@nvidia.com' }
 
     render(
       <MainLayout isAuthenticated={true} user={user} onSignIn={onSignIn} onSignOut={onSignOut} />
@@ -172,7 +172,7 @@ describe('MainLayout', () => {
 
     expect(mockStartNewSessionDraft).toHaveBeenCalledOnce()
     expect(mockClearSessionUrl).toHaveBeenCalledOnce()
-    expect(mockCloseRightPanel).toHaveBeenCalledOnce()
+    expect(mockOpenRightPanel).toHaveBeenCalledWith('data-sources')
   })
 
   test('disables new session action while shallow streaming is active', () => {

frontends/ui/src/features/layout/components/MainLayout.tsx

@@ -74,7 +74,7 @@ export const MainLayout: FC<MainLayoutProps> = ({
     deepResearchOwnerConversationId,
   } = useChatStore()
 
-  const { rightPanel, closeRightPanel } = useLayoutStore()
+  const { rightPanel, openRightPanel } = useLayoutStore()
   const prefersReducedMotion = useReducedMotion()
 
   // Deep research SSE hook - manages connection when deep research starts
@@ -93,11 +93,12 @@ export const MainLayout: FC<MainLayoutProps> = ({
   )
 
   // Start a new unsaved draft session and clear URL until first interaction.
+  // Open Data Sources panel so it stays visible (default panel for new sessions).
   const handleNewSession = useCallback(() => {
     startNewSessionDraft()
     clearSessionUrl()
-    closeRightPanel()
-  }, [startNewSessionDraft, clearSessionUrl, closeRightPanel])
+    openRightPanel('data-sources')
+  }, [startNewSessionDraft, clearSessionUrl, openRightPanel])
 
   // Wrap deleteConversation to clear URL if deleting current session
   const handleDeleteSession = useCallback(

frontends/ui/src/features/layout/store.spec.ts

@@ -6,10 +6,10 @@ import { useLayoutStore } from './store'
 
 describe('useLayoutStore', () => {
   beforeEach(() => {
-    // Reset store to initial state before each test
+    // Reset store to initial state before each test (matches store.ts initialState)
     useLayoutStore.setState({
       isSessionsPanelOpen: false,
-      rightPanel: null,
+      rightPanel: 'data-sources',
       researchPanelTab: 'plan',
       dataSourcesPanelTab: 'connections',
       theme: 'system',
@@ -21,7 +21,7 @@ describe('useLayoutStore', () => {
       const state = useLayoutStore.getState()
 
       expect(state.isSessionsPanelOpen).toBe(false)
-      expect(state.rightPanel).toBeNull()
+      expect(state.rightPanel).toBe('data-sources')
       expect(state.researchPanelTab).toBe('plan')
       expect(state.dataSourcesPanelTab).toBe('connections')
     })
@@ -110,6 +110,8 @@ describe('useLayoutStore', () => {
     })
 
     test('handles closing when already closed', () => {
+      useLayoutStore.setState({ rightPanel: null })
+
       useLayoutStore.getState().closeRightPanel()
 
       expect(useLayoutStore.getState().rightPanel).toBeNull()

frontends/ui/src/features/layout/store.ts

@@ -23,7 +23,7 @@ import { WEB_SEARCH_SOURCE_ID } from './data-sources'
 
 const initialState: LayoutState = {
   isSessionsPanelOpen: false,
-  rightPanel: null,
+  rightPanel: 'data-sources',
   researchPanelTab: 'plan',
   dataSourcesPanelTab: 'connections',
   enabledDataSourceIds: [], // Start empty, populated when data sources are fetched
@@ -91,6 +91,7 @@ export const useLayoutStore = create<LayoutStore>()(
 
           // data_sources is already filtered (knowledge_layer removed) by the client
           // Only enable web_search by default - user must manually enable other sources
+          // This ensures ECI sources are opt-in and prevents accidental data access
           const enabledIds = response.data_sources
             .filter((source) => source.id === WEB_SEARCH_SOURCE_ID)
             .map((source) => source.id)

frontends/ui/src/features/layout/types.ts

@@ -75,7 +75,7 @@ export interface LayoutActions {
   setTheme: (theme: ThemeMode) => void
   /** Fetch data sources from API. Only web_search is enabled by default */
   fetchDataSources: (authToken?: string) => Promise<void>
-  /** Disable all non-web sources (keep only web_search enabled) */
+  /** Disable non-web sources (keep only web_search enabled) */
   disableNonWebSources: () => void
   /** Set available data sources (from API) */
   setAvailableDataSources: (sources: DataSourceFromAPI[]) => void