fix(#76): correct frontend availability, retry, and live recovery semantics

Make response freshness React Query-safe, retry the failed Weekend/Preview/Briefing resources with busy gating, preserve distinct embedded Preview notices, and clear fatal Live errors once SSE supplies usable timing.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/weekend/PreSessionView.tsx

@@ -4,6 +4,7 @@ import type { WeekendContext } from '../../types'
 import { RacePreviewPage } from '../../pages/RacePreviewPage'
 import { ChampionshipRoundStrip, CountdownDisplay, Flag, SessionRail, railNodes } from './shared'
 import { meetingIdentity } from '../../lib/weekendContext'
+import type { DataAvailability } from '../../lib/availability'
 
 /**
  * PreSessionView folds the race preview surface into the Weekend home so there is
@@ -14,7 +15,16 @@ import { meetingIdentity } from '../../lib/weekendContext'
  * Canonical meeting/session identity is passed into Preview so the nested surface
  * cannot independently re-resolve a different current weekend.
  */
-export function PreSessionView({ context, now }: { context: WeekendContext; now: Date }) {
+export function PreSessionView({
+  context,
+  now,
+  shellAvailability = null,
+}: {
+  context: WeekendContext
+  now: Date
+  /** Weekend shell notice already shown — Preview dedupes only an equivalent kind. */
+  shellAvailability?: DataAvailability | null
+}) {
   const meeting = context.next_meeting ?? context.focus_meeting
   const identity = meetingIdentity(meeting)
   const next = context.next_session?.session
@@ -52,6 +62,7 @@ export function PreSessionView({ context, now }: { context: WeekendContext; now:
           embedded
           meeting={meeting}
           season={context.season ?? meeting?.year}
+          shellAvailability={shellAvailability}
         />
       </div>
 

frontend/src/hooks/useWeekendContext.ts

@@ -25,9 +25,9 @@ export interface UseWeekendContextResult {
   /** True when championship or news supplements failed while context succeeded. */
   supplementsLimited: boolean
   now: Date
-  /** Refetch the canonical weekend-context read. */
+  /** Refetch canonical context and/or failed supplements as appropriate. */
   refetch: () => void
-  /** True while a canonical refetch is in flight. */
+  /** True while a relevant refetch is in flight. */
   isFetching: boolean
 }
 
@@ -88,15 +88,42 @@ export function useWeekendContext(): UseWeekendContextResult {
     [canonical],
   )
 
+  // Keep Limited visible while a failed supplement is refetching so Retry can
+  // expose disabled/aria-busy. React Query v5 clears isError during that refetch.
+  const supplementDegraded = (q: {
+    isError: boolean
+    isFetching: boolean
+    isFetched: boolean
+    data: unknown
+  }) => q.isError || (q.isFetching && q.isFetched && q.data == null)
+
   const supplementsLimited =
     canonicalReady &&
-    ((championshipQuery.isError && !championshipQuery.isFetching) ||
-      (newsQuery.isError && !newsQuery.isFetching))
+    (supplementDegraded(championshipQuery) || supplementDegraded(newsQuery))
 
   let loadState: WeekendLoadState = 'loading'
   if (contextQuery.isError) loadState = 'error'
   else if (canonicalReady) loadState = 'ready'
 
+  const refetch = () => {
+    if (!canonicalReady) {
+      if (!contextQuery.isFetching) void contextQuery.refetch()
+      return
+    }
+    // Freshness notice Retry refreshes the canonical context.
+    if (availabilityNotice && !contextQuery.isFetching) {
+      void contextQuery.refetch()
+    }
+    // Limited Retry must hit the failed supplements — not merely context.
+    // Gate on degraded (error or in-flight post-error refetch), not isError alone.
+    if (championshipQuery.isError && !championshipQuery.isFetching) {
+      void championshipQuery.refetch()
+    }
+    if (newsQuery.isError && !newsQuery.isFetching) {
+      void newsQuery.refetch()
+    }
+  }
+
   return {
     context: canonical,
     loadState,
@@ -106,9 +133,8 @@ export function useWeekendContext(): UseWeekendContextResult {
     availabilityNotice,
     supplementsLimited,
     now: nowDate,
-    refetch: () => {
-      if (!contextQuery.isFetching) void contextQuery.refetch()
-    },
-    isFetching: contextQuery.isFetching,
+    refetch,
+    isFetching:
+      contextQuery.isFetching || championshipQuery.isFetching || newsQuery.isFetching,
   }
 }

frontend/src/lib/availability.ts

@@ -74,3 +74,16 @@ export function weekendContextNotice(
   }
   return null
 }
+
+/**
+ * Embedded Preview should disclose its own freshness unless the Weekend shell
+ * already shows an equivalent notice (same DataAvailability kind).
+ */
+export function shouldShowEmbeddedNotice(
+  notice: DataAvailability | null | undefined,
+  shellNotice: DataAvailability | null | undefined,
+): boolean {
+  if (!notice) return false
+  if (!shellNotice) return true
+  return notice !== shellNotice
+}

frontend/src/lib/fetch.ts

@@ -1,5 +1,7 @@
 /** Bounded fetch helpers for primary-route resilience. */
 
+import { replaceEqualDeep } from '@tanstack/react-query'
+
 export const DEFAULT_FETCH_TIMEOUT_MS = 15_000
 
 /** CORS-readable success provenance headers from the Go API. */
@@ -55,6 +57,35 @@ export function rememberResponseAvailability(
   responseAvailability.set(data, meta)
 }
 
+/** Drop availability metadata from a payload (e.g. after a header-less refetch). */
+export function clearResponseAvailability(data: object): void {
+  responseAvailability.delete(data)
+}
+
+/**
+ * React Query structural sharing that keeps header availability in sync.
+ *
+ * Default `replaceEqualDeep` reuses the previous object when JSON is equal, which
+ * would leave stale WeakMap metadata attached after a stale→fresh (or fresh→partial)
+ * refetch of an identical body. Always re-bind the latest fetch's metadata onto the
+ * object that lands in the query cache.
+ */
+export function availabilityAwareStructuralSharing<T>(
+  oldData: T | undefined,
+  newData: T,
+): T {
+  const meta = getResponseAvailability(newData)
+  const shared = replaceEqualDeep(oldData, newData) as T
+  if (shared !== null && typeof shared === 'object') {
+    if (meta) {
+      rememberResponseAvailability(shared as object, meta)
+    } else {
+      clearResponseAvailability(shared as object)
+    }
+  }
+  return shared
+}
+
 export type ApiErrorKind = 'http' | 'timeout' | 'abort' | 'network'
 
 export class ApiError extends Error {

frontend/src/lib/queryClient.ts

@@ -0,0 +1,16 @@
+import { QueryClient } from '@tanstack/react-query'
+import { availabilityAwareStructuralSharing } from './fetch'
+
+/** Shared QueryClient defaults — availability-aware structural sharing for header metadata. */
+export function createAppQueryClient(): QueryClient {
+  return new QueryClient({
+    defaultOptions: {
+      queries: {
+        staleTime: 30_000,
+        // Explicit Retry on RouteState — avoid automatic retry storms.
+        retry: false,
+        structuralSharing: availabilityAwareStructuralSharing,
+      },
+    },
+  })
+}

frontend/src/main.tsx

@@ -1,19 +1,12 @@
 import React from 'react'
 import ReactDOM from 'react-dom/client'
 import { RouterProvider } from '@tanstack/react-router'
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { QueryClientProvider } from '@tanstack/react-query'
+import { createAppQueryClient } from './lib/queryClient'
 import { router } from './router'
 import './styles/app.css'
 
-const queryClient = new QueryClient({
-  defaultOptions: {
-    queries: {
-      staleTime: 30_000,
-      // Explicit Retry on RouteState — avoid automatic retry storms.
-      retry: false,
-    },
-  },
-})
+const queryClient = createAppQueryClient()
 
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>

frontend/src/pages/BriefingPage.tsx

@@ -517,12 +517,35 @@ export function BriefingPage() {
   const hasDigest = meetings.length > 0
   const showEmpty = tagFiltered.length === 0 && grouped.recent.length === 0
 
+  const supplementsFetching =
+    meetingsQuery.isFetching || hubQuery.isFetching || seasonsQuery.isFetching
+  // React Query v5 clears isError while a post-error refetch is in flight
+  // (status → pending). Keep Limited mounted so Retry can show aria-busy.
+  const supplementDegraded = (q: {
+    isError: boolean
+    isFetching: boolean
+    isFetched: boolean
+    data: unknown
+  }) => q.isError || (q.isFetching && q.isFetched && q.data == null)
   const supplementsLimited =
     !isLoading &&
     !isError &&
-    ((meetingsQuery.isError && !meetingsQuery.isFetching) ||
-      (hubQuery.isError && !hubQuery.isFetching) ||
-      (seasonsQuery.isError && !seasonsQuery.isFetching))
+    (supplementDegraded(meetingsQuery) ||
+      supplementDegraded(hubQuery) ||
+      supplementDegraded(seasonsQuery))
+  const supplementsRetrying = supplementsLimited && supplementsFetching
+
+  const retrySupplements = () => {
+    if (supplementDegraded(meetingsQuery) && !meetingsQuery.isFetching) {
+      void meetingsQuery.refetch()
+    }
+    if (supplementDegraded(hubQuery) && !hubQuery.isFetching) {
+      void hubQuery.refetch()
+    }
+    if (supplementDegraded(seasonsQuery) && !seasonsQuery.isFetching) {
+      void seasonsQuery.refetch()
+    }
+  }
 
   const newsAvailability = noticeFromResponse(allNews, { includeLocal: true })
   const hubAvailability = noticeFromResponse(hub, { includeLocal: false })
@@ -560,11 +583,8 @@ export function BriefingPage() {
             <DataNotice
               availability="limited"
               message="Weekend grouping or driver tags are limited. Articles are still available."
-              onRetry={() => {
-                if (meetingsQuery.isError && !meetingsQuery.isFetching) void meetingsQuery.refetch()
-                if (hubQuery.isError && !hubQuery.isFetching) void hubQuery.refetch()
-                if (seasonsQuery.isError && !seasonsQuery.isFetching) void seasonsQuery.refetch()
-              }}
+              onRetry={retrySupplements}
+              retrying={supplementsRetrying}
               testId="briefing-data-notice"
             />
           )}

frontend/src/pages/LiveTimingPage.tsx

@@ -304,9 +304,14 @@ export function LiveTimingPage() {
   // feed-health truth rather than "Connection lost" + "Feed healthy".
   const feedHealth = effectiveFeedHealth(streamStatus, phase)
 
+  // A usable SSE/stream snapshot must not coexist with the fatal initial-state
+  // error — gate once live or retained archive data arrives.
+  const hasUsableStreamData = Boolean(activeSnapshot) || Boolean(archiveSnapshot)
+  const showInitialError = isError && !hasUsableStreamData
+
   return (
     <div className="page live-page" data-testid="live-page" data-phase={phase}>
-      {isError && (
+      {showInitialError && (
         <RouteState
           kind="error"
           title="Live timing unavailable"
@@ -334,7 +339,7 @@ export function LiveTimingPage() {
         </div>
       )}
 
-      {phase === 'connecting' && (isLoading || !liveStateFetched) && (
+      {phase === 'connecting' && (isLoading || !liveStateFetched) && !hasUsableStreamData && (
         <RouteState
           kind="loading"
           title="connecting to live timing…"

frontend/src/pages/RacePreviewPage.tsx

@@ -10,7 +10,12 @@ import {
   fetchTrackOutline,
 } from '../api'
 import { DataNotice, RouteState } from '../components/RouteState'
-import { noticeFromResponse, noticeMessage } from '../lib/availability'
+import {
+  noticeFromResponse,
+  noticeMessage,
+  shouldShowEmbeddedNotice,
+  type DataAvailability,
+} from '../lib/availability'
 import { userFacingError } from '../lib/fetch'
 import { countryAccent, countryFlag, formatGpDateRange } from '../lib/gpIdentity'
 import {
@@ -272,12 +277,18 @@ export interface RacePreviewPageProps {
   season?: number
   /** Embedded under Weekend — identity failures stay non-blocking. */
   embedded?: boolean
+  /**
+   * Availability already disclosed by the Weekend shell. Embedded Preview
+   * suppresses only an equivalent notice kind; distinct truth stays visible.
+   */
+  shellAvailability?: DataAvailability | null
 }
 
 export function RacePreviewPage({
   meeting: canonicalMeeting,
   season: canonicalSeason,
   embedded = false,
+  shellAvailability = null,
 }: RacePreviewPageProps = {}) {
   const [now, setNow] = useState(() => Date.now())
 
@@ -398,6 +409,17 @@ export function RacePreviewPage({
     noticeFromResponse(sessionsQuery.data, { includeLocal: false }) ??
     noticeFromResponse(priorResultsQuery.data, { includeLocal: false })
 
+  const showFreshnessNotice =
+    Boolean(dataNotice) &&
+    (!embedded || shouldShowEmbeddedNotice(dataNotice, shellAvailability))
+
+  const sessionsFailed = sessionsQuery.isError
+  const sessionsRetrying = sessionsQuery.isFetching
+
+  const retrySessions = () => {
+    if (!sessionsQuery.isFetching) void sessionsQuery.refetch()
+  }
+
   if (identityLoading) {
     return (
       <div className={embedded ? 'preview-embedded' : 'page'} data-testid="preview-loading">
@@ -455,8 +477,7 @@ export function RacePreviewPage({
       data-meeting-key={previewMeeting.meeting_key}
       data-embedded={embedded ? 'true' : undefined}
     >
-      {/* Weekend shell owns availability disclosure when Preview is embedded. */}
-      {!embedded && dataNotice && (
+      {showFreshnessNotice && dataNotice && (
         <DataNotice
           availability={dataNotice}
           message={noticeMessage(dataNotice)}
@@ -464,6 +485,18 @@ export function RacePreviewPage({
         />
       )}
 
+      {sessionsFailed && (
+        <RouteState
+          kind="error"
+          title="Session schedule unavailable"
+          error={sessionsQuery.error}
+          onRetry={retrySessions}
+          retrying={sessionsRetrying}
+          testId="preview-sessions-error"
+          retryTestId="preview-sessions-retry"
+        />
+      )}
+
       {/* Embedded Weekend already shows the canonical countdown header — skip the duplicate. */}
       {!embedded && (
         <PreviewHeader
@@ -475,6 +508,20 @@ export function RacePreviewPage({
         />
       )}
 
+      {/* Embedded: still surface recovered schedule once sessions load. */}
+      {embedded && sessions.length > 0 && (
+        <div className="preview-schedule" data-testid="preview-schedule">
+          {sessions.map((session) => (
+            <div key={session.session_key} className="preview-schedule-item">
+              <span className="preview-schedule-name">{session.session_name}</span>
+              <span className="preview-schedule-time">
+                {formatSessionScheduleTime(session.date_start)}
+              </span>
+            </div>
+          ))}
+        </div>
+      )}
+
       <div className="preview-grid">
         <TrackOutlineCard
           outline={trackOutlineQuery.data}

frontend/src/pages/WeekendPage.tsx

@@ -23,16 +23,18 @@ interface RenderArgs {
   briefing: WeekendBriefingItem[]
   /** When true (the /preview alias), foreground the preparation surface. */
   preview: boolean
+  /** Availability already disclosed by the Weekend shell (for Preview dedupe). */
+  shellAvailability: DataAvailability | null
 }
 
 function renderState(view: WeekendViewState, args: RenderArgs) {
-  const { context, now, championship, briefing, preview } = args
+  const { context, now, championship, briefing, preview, shellAvailability } = args
   // The /preview alias always resolves to the preparation surface as long as
   // there is a next event to prepare for, regardless of the temporal state. This
   // keeps saved /preview links and the "Prepare for …" CTA meaningful instead of
   // redirecting straight back to the same between-races screen.
   if (preview && context.next_meeting) {
-    return <PreSessionView context={context} now={now} />
+    return <PreSessionView context={context} now={now} shellAvailability={shellAvailability} />
   }
 
   switch (view) {
@@ -56,7 +58,7 @@ function renderState(view: WeekendViewState, args: RenderArgs) {
     case 'session_live':
       return <LiveHandoffView context={context} />
     case 'pre_session':
-      return <PreSessionView context={context} now={now} />
+      return <PreSessionView context={context} now={now} shellAvailability={shellAvailability} />
     default:
       return <WeekendLimited season={context.season} />
   }
@@ -144,6 +146,7 @@ export function WeekendPage({
   }
 
   const view = resolveViewState(context)
+  const shellAvailability = availabilityNotice ?? (supplementsLimited ? 'limited' : null)
 
   return (
     <main
@@ -164,7 +167,14 @@ export function WeekendPage({
         onRetry={refetch}
         retrying={isFetching}
       />
-      {renderState(view, { context, now, championship, briefing, preview })}
+      {renderState(view, {
+        context,
+        now,
+        championship,
+        briefing,
+        preview,
+        shellAvailability,
+      })}
     </main>
   )
 }

frontend/src/test/BriefingPage.test.tsx

@@ -219,5 +219,36 @@ describe('BriefingPage digest layout', () => {
     })
     expect(screen.getByText('Verstappen sets the pace in Bahrain')).toBeInTheDocument()
     expect(screen.queryByTestId('briefing-error')).not.toBeInTheDocument()
+
+    let meetingsCalls = 1
+    let hubCalls = 1
+    let resolveMeetings!: (value: Meeting[]) => void
+    let resolveHub!: (value: ChampionshipHub) => void
+    mockFetchSeasonMeetings.mockImplementation(
+      () =>
+        new Promise<Meeting[]>((resolve) => {
+          meetingsCalls += 1
+          resolveMeetings = resolve
+        }),
+    )
+    mockFetchHub.mockImplementation(
+      () =>
+        new Promise<ChampionshipHub>((resolve) => {
+          hubCalls += 1
+          resolveHub = resolve
+        }),
+    )
+
+    fireEvent.click(screen.getByRole('button', { name: 'Retry' }))
+    await waitFor(() => expect(screen.getByRole('button', { name: 'Retrying…' })).toBeDisabled())
+    expect(screen.getByRole('button', { name: 'Retrying…' })).toHaveAttribute('aria-busy', 'true')
+    fireEvent.click(screen.getByRole('button', { name: 'Retrying…' }))
+    expect(meetingsCalls).toBe(2)
+    expect(hubCalls).toBe(2)
+
+    resolveMeetings([bahrain, monaco])
+    resolveHub(hub)
+    await waitFor(() => expect(screen.queryByTestId('briefing-data-notice')).not.toBeInTheDocument())
+    expect(screen.getByText('Verstappen sets the pace in Bahrain')).toBeInTheDocument()
   })
 })

frontend/src/test/LiveTimingPage.test.tsx

@@ -356,7 +356,7 @@ describe('LiveTimingPage', () => {
     expect(screen.queryByText('LIVE SESSION')).not.toBeInTheDocument()
   })
 
-  it('shows the inactive weekend context when nothing is live or retained', async () => {
+  it('shows inactive handoff when nothing is live or retained', async () => {
     renderPage(
       { is_live: false, data: null },
       {
@@ -392,4 +392,96 @@ describe('LiveTimingPage', () => {
       expect(screen.getByTestId('live-handoff-next')).toHaveTextContent('Practice 1'),
     )
   })
+
+  it('clears fatal initial error once SSE supplies a live snapshot', async () => {
+    type Listener = (event: { data: string }) => void
+    class RecoveringEventSource {
+      onopen: (() => void) | null = null
+      onerror: (() => void) | null = null
+      private listeners = new Map<string, Listener[]>()
+      static latest: RecoveringEventSource | null = null
+      constructor() {
+        RecoveringEventSource.latest = this
+        setTimeout(() => this.onopen?.(), 0)
+      }
+      addEventListener(type: string, listener: Listener) {
+        const list = this.listeners.get(type) ?? []
+        list.push(listener)
+        this.listeners.set(type, list)
+      }
+      emit(type: string, data: unknown) {
+        for (const listener of this.listeners.get(type) ?? []) {
+          listener({ data: JSON.stringify(data) })
+        }
+      }
+      close() {}
+    }
+
+    Object.defineProperty(window, 'EventSource', {
+      value: RecoveringEventSource,
+      writable: true,
+      configurable: true,
+    })
+
+    mockFetchLiveState.mockRejectedValue(new Error('API 503: live state unavailable'))
+    mockFetchLiveTrackOutline.mockResolvedValue({
+      circuit_key: 1,
+      points: [],
+      bounds: { minX: 0, maxX: 1, minY: 0, maxY: 1 },
+    })
+    mockFetchWeekendContext.mockResolvedValue({
+      temporal_state: 'no_season',
+      championship_round: 0,
+      total_championship_rounds: 0,
+    })
+
+    render(
+      <QueryClientProvider
+        client={new QueryClient({ defaultOptions: { queries: { retry: false } } })}
+      >
+        <LiveTimingPage />
+      </QueryClientProvider>,
+    )
+
+    expect(await screen.findByTestId('live-initial-error')).toBeInTheDocument()
+    expect(screen.getByText(/Live timing unavailable/i)).toBeInTheDocument()
+
+    await act(async () => {
+      RecoveringEventSource.latest?.emit('snapshot', {
+        is_live: true,
+        data: raceSnapshot,
+      })
+    })
+
+    await waitFor(() => expect(screen.getByText('Timing Tower')).toBeInTheDocument())
+    expect(screen.queryByTestId('live-initial-error')).not.toBeInTheDocument()
+    expect(screen.getByTestId('live-page')).toHaveAttribute('data-phase', 'live')
+    expect(screen.queryByText(/Live timing unavailable/i)).not.toBeInTheDocument()
+  })
+
+  it('keeps bounded initial error + Retry when no stream data arrives', async () => {
+    mockFetchLiveState.mockRejectedValue(new Error('API 503: live state unavailable'))
+    mockFetchLiveTrackOutline.mockResolvedValue({
+      circuit_key: 1,
+      points: [],
+      bounds: { minX: 0, maxX: 1, minY: 0, maxY: 1 },
+    })
+    mockFetchWeekendContext.mockResolvedValue({
+      temporal_state: 'no_season',
+      championship_round: 0,
+      total_championship_rounds: 0,
+    })
+
+    render(
+      <QueryClientProvider
+        client={new QueryClient({ defaultOptions: { queries: { retry: false } } })}
+      >
+        <LiveTimingPage />
+      </QueryClientProvider>,
+    )
+
+    expect(await screen.findByTestId('live-initial-error')).toBeInTheDocument()
+    expect(screen.getByRole('button', { name: 'Retry' })).toBeEnabled()
+    expect(screen.queryByText('Timing Tower')).not.toBeInTheDocument()
+  })
 })

frontend/src/test/RacePreviewPage.test.tsx

@@ -2,6 +2,7 @@ import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { render, screen, waitFor, fireEvent } from '@testing-library/react'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { RouterProvider, createRouter, createRootRoute, createRoute } from '@tanstack/react-router'
+import { rememberResponseAvailability } from '../lib/fetch'
 import { RacePreviewPage } from '../pages/RacePreviewPage'
 import { ApiError } from '../lib/fetch'
 import type { ChampHubDriver, ChampionshipHub, EnrichedGrid, EnrichedResult, Meeting, Session, TrackOutline } from '../types'
@@ -175,7 +176,12 @@ const outline: TrackOutline = {
   bounds: { minX: 0, maxX: 1, minY: 0, maxY: 1 },
 }
 
-function renderPage(props?: { meeting?: Meeting; season?: number; embedded?: boolean }) {
+function renderPage(props?: {
+  meeting?: Meeting
+  season?: number
+  embedded?: boolean
+  shellAvailability?: 'local' | 'partial' | 'stale' | 'archive' | 'limited' | 'missing' | null
+}) {
   const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } })
   const Page = () => <RacePreviewPage {...props} />
   const rootRoute = createRootRoute({
@@ -288,7 +294,7 @@ describe('RacePreviewPage', () => {
       return []
     })
 
-    renderPage({ meeting: upcomingMeeting, season: 2099, embedded: true })
+    renderPage({ meeting: upcomingMeeting, season: 2099, embedded: true, shellAvailability: 'partial' })
 
     await waitFor(() => expect(screen.getByTestId('preview-page')).toBeInTheDocument())
     expect(screen.getByTestId('preview-page')).toHaveAttribute('data-meeting-key', '100')
@@ -298,10 +304,76 @@ describe('RacePreviewPage', () => {
     expect(mockFetchMeetings).not.toHaveBeenCalledWith(2099, expect.anything(), expect.anything())
     expect(mockFetchSessions).toHaveBeenCalledWith(100, 'auto', expect.anything())
     expect(screen.queryByTestId('preview-header')).not.toBeInTheDocument()
-    // Weekend shell owns availability disclosure — no stacked Preview notice.
+  })
+
+  it('dedupes an equivalent shell notice but shows distinct Preview freshness', async () => {
+    mockFetchSessions.mockImplementation(async (meetingKey: number) => {
+      if (meetingKey === 100) return sessions
+      if (meetingKey === 90) return [priorRaceSession]
+      return []
+    })
+    mockFetchMeetings.mockImplementation(async (year: number) => {
+      if (year === 2098) return [priorMeeting]
+      return []
+    })
+
+    const staleHub = { ...hub }
+    rememberResponseAvailability(staleHub, { source: 'openf1', freshness: 'stale' })
+    mockFetchChampionshipHub.mockResolvedValue(staleHub)
+
+    const distinct = renderPage({
+      meeting: upcomingMeeting,
+      season: 2099,
+      embedded: true,
+      shellAvailability: 'partial',
+    })
+    await waitFor(() => expect(screen.getByTestId('preview-data-notice')).toHaveTextContent(/Stale/i))
+    distinct.unmount()
+
+    const partialHub = { ...hub }
+    rememberResponseAvailability(partialHub, { source: 'openf1', freshness: 'partial' })
+    mockFetchChampionshipHub.mockResolvedValue(partialHub)
+
+    renderPage({
+      meeting: upcomingMeeting,
+      season: 2099,
+      embedded: true,
+      shellAvailability: 'partial',
+    })
+    await waitFor(() => expect(screen.getByTestId('preview-page')).toBeInTheDocument())
     expect(screen.queryByTestId('preview-data-notice')).not.toBeInTheDocument()
   })
 
+  it('shows sanitized sessions failure with Retry that refetches once', async () => {
+    let sessionCalls = 0
+    mockFetchSessions.mockImplementation(async (meetingKey: number) => {
+      if (meetingKey !== 100) return [priorRaceSession]
+      sessionCalls += 1
+      if (sessionCalls === 1) {
+        throw new ApiError('http', 'API 500: sessions boom', { status: 500 })
+      }
+      return sessions
+    })
+    mockFetchMeetings.mockImplementation(async (year: number) => {
+      if (year === 2098) return [priorMeeting]
+      return []
+    })
+
+    renderPage({ meeting: upcomingMeeting, season: 2099, embedded: true })
+
+    await waitFor(() => expect(screen.getByTestId('preview-sessions-error')).toBeInTheDocument())
+    expect(screen.getByTestId('preview-sessions-error')).not.toHaveTextContent(/API 500|sessions boom/i)
+    expect(screen.getByTestId('preview-page')).toBeInTheDocument()
+
+    const retry = screen.getByTestId('preview-sessions-retry')
+    fireEvent.click(retry)
+    fireEvent.click(retry)
+
+    await waitFor(() => expect(screen.getByTestId('preview-schedule')).toHaveTextContent('FP1'))
+    expect(sessionCalls).toBe(2)
+    expect(screen.queryByTestId('preview-sessions-error')).not.toBeInTheDocument()
+  })
+
   it('sanitizes raw HTTP errors and offers a guarded keyboard Retry', async () => {
     mockFetchSeasons.mockRejectedValue(
       new ApiError('http', 'API 500: Internal Server Error', { status: 500 }),

frontend/src/test/WeekendPage.test.tsx

@@ -50,6 +50,7 @@ import {
   fetchStartingGrid,
   fetchTrackOutline,
 } from '../api'
+import { rememberResponseAvailability } from '../lib/fetch'
 
 const mockContext = vi.mocked(fetchWeekendContext)
 const mockHub = vi.mocked(fetchChampionshipHub)
@@ -432,19 +433,99 @@ describe('WeekendPage canonical contract rendering', () => {
         }),
       }),
     )
-    // Force identity path by omitting meeting prop simulation: sessions for supplements fail,
-    // but shell stays. Actually with canonical meeting, identity never errors — force
-    // championship/track failures instead, and separately test standalone raw error below.
-    mockSessions.mockRejectedValue(new Error('API 500: sessions boom'))
-    mockHub.mockRejectedValue(new Error('API 429: rate limited'))
+    let sessionCalls = 0
+    mockSessions.mockImplementation(async (meetingKey: number) => {
+      if (meetingKey !== 2) return []
+      sessionCalls += 1
+      if (sessionCalls === 1) throw new Error('API 500: sessions boom')
+      return [
+        session({
+          session_key: 21,
+          session_name: 'Practice 1',
+          meeting_key: 2,
+          date_start: '2026-07-24T09:00:00Z',
+        }),
+      ]
+    })
 
     renderAt('/')
     await waitFor(() => expect(screen.getByTestId('wk-pre-head')).toBeInTheDocument())
     expect(screen.getByTestId('wk-pre-head')).toHaveTextContent('Hungarian Grand Prix')
-    expect(screen.getByTestId('weekend-pre-session')).toBeInTheDocument()
-    // Nested preview still mounts with canonical meeting; section errors are sanitized.
-    await waitFor(() => expect(screen.getByTestId('preview-page')).toBeInTheDocument())
-    expect(screen.queryByText(/API 500|API 429|sessions boom/i)).not.toBeInTheDocument()
+    await waitFor(() => expect(screen.getByTestId('preview-sessions-error')).toBeInTheDocument())
+    expect(screen.queryByText(/API 500|sessions boom/i)).not.toBeInTheDocument()
+
+    fireEvent.click(screen.getByTestId('preview-sessions-retry'))
+    await waitFor(() => expect(screen.getByTestId('preview-schedule')).toHaveTextContent('Practice 1'))
+    expect(sessionCalls).toBe(2)
+    expect(screen.queryByTestId('preview-sessions-error')).not.toBeInTheDocument()
+  })
+
+  it('Limited Retry refetches failed championship/news supplements once', async () => {
+    mockContext.mockResolvedValue(context({ temporal_state: 'between_weekends' }))
+    let hubCalls = 0
+    let newsCalls = 0
+    mockHub.mockImplementation(async () => {
+      hubCalls += 1
+      if (hubCalls === 1) throw new Error('API 503: hub')
+      return hub
+    })
+    mockNews.mockImplementation(async () => {
+      newsCalls += 1
+      if (newsCalls === 1) throw new Error('API 503: news')
+      return []
+    })
+
+    renderAt('/')
+    await waitFor(() => expect(screen.getByTestId('weekend-data-notice')).toHaveTextContent(/Limited/i))
+    const retry = screen.getByTestId('weekend-data-notice').querySelector('button')!
+    expect(retry).toBeEnabled()
+    fireEvent.click(retry)
+    fireEvent.click(retry)
+
+    await waitFor(() => expect(screen.queryByTestId('weekend-data-notice')).not.toBeInTheDocument())
+    expect(hubCalls).toBe(2)
+    expect(newsCalls).toBe(2)
+    // Canonical context is not the failed resource — only one initial fetch.
+    expect(mockContext).toHaveBeenCalledTimes(1)
+  })
+
+  it('pre_session keeps shell Partial while disclosing distinct Preview stale', async () => {
+    const next = meeting({
+      meeting_key: 2,
+      meeting_name: 'Hungarian Grand Prix',
+      date_start: '2026-07-24T09:00:00Z',
+    })
+    mockContext.mockResolvedValue(
+      context({
+        temporal_state: 'pre_session',
+        next_meeting: next,
+        focus_meeting: next,
+        next_session: ctxSession({
+          session: session({
+            session_key: 21,
+            session_name: 'Practice 1',
+            meeting_key: 2,
+            date_start: '2026-07-24T09:00:00Z',
+          }),
+          meeting: next,
+          availability: availability({ freshness: 'partial', local_analysis: 'partial' }),
+        }),
+      }),
+    )
+    mockSessions.mockResolvedValue([
+      session({
+        session_key: 21,
+        session_name: 'Practice 1',
+        meeting_key: 2,
+        date_start: '2026-07-24T09:00:00Z',
+      }),
+    ])
+    rememberResponseAvailability(hub, { source: 'openf1', freshness: 'stale' })
+    mockHub.mockResolvedValue(hub)
+
+    renderAt('/')
+    await waitFor(() => expect(screen.getByTestId('weekend-data-notice')).toHaveTextContent(/Partial/i))
+    await waitFor(() => expect(screen.getByTestId('preview-data-notice')).toHaveTextContent(/Stale/i))
   })
 
   it('restores Race Hub meeting/session focus from the Weekend URL search contract', async () => {

frontend/src/test/availability.test.ts

@@ -1,6 +1,8 @@
 import { describe, expect, it, vi, beforeEach, afterEach } from 'vitest'
+import { QueryClient, QueryObserver } from '@tanstack/react-query'
 import {
   apiFetch,
+  availabilityAwareStructuralSharing,
   clearApiFetchInflight,
   DATA_FRESHNESS_HEADER,
   DATA_SOURCE_HEADER,
@@ -10,6 +12,7 @@ import {
 import {
   noticeFromFreshness,
   noticeFromResponse,
+  shouldShowEmbeddedNotice,
   weekendContextNotice,
 } from '../lib/availability'
 import type { WeekendContext } from '../types'
@@ -85,6 +88,13 @@ describe('response availability metadata', () => {
     expect(noticeFromResponse(hub)).toBe('stale')
   })
 
+  it('dedupes only equivalent embedded Preview notices', () => {
+    expect(shouldShowEmbeddedNotice('stale', 'partial')).toBe(true)
+    expect(shouldShowEmbeddedNotice('partial', 'partial')).toBe(false)
+    expect(shouldShowEmbeddedNotice('stale', null)).toBe(true)
+    expect(shouldShowEmbeddedNotice(null, 'partial')).toBe(false)
+  })
+
   it('derives Weekend Context notices from typed session freshness, skipping routine local', () => {
     const context: WeekendContext = {
       season: 2026,
@@ -128,4 +138,84 @@ describe('response availability metadata', () => {
     }
     expect(weekendContextNotice(localOnly)).toBeNull()
   })
+
+  it('updates metadata when structural sharing reuses an equal JSON object', () => {
+    const body = { season: 2026, drivers: [{ points: 1 }] }
+    const first = structuredClone(body)
+    const second = structuredClone(body)
+    rememberResponseAvailability(first, { source: 'openf1', freshness: 'stale' })
+    rememberResponseAvailability(second, { source: 'openf1', freshness: 'fresh' })
+
+    const shared = availabilityAwareStructuralSharing(first, second)
+    expect(shared).toBe(first)
+    expect(getResponseAvailability(shared)).toEqual({ source: 'openf1', freshness: 'fresh' })
+    expect(noticeFromResponse(shared)).toBeNull()
+
+    const third = structuredClone(body)
+    rememberResponseAvailability(third, { source: 'openf1', freshness: 'partial' })
+    const sharedAgain = availabilityAwareStructuralSharing(shared, third)
+    expect(sharedAgain).toBe(first)
+    expect(noticeFromResponse(sharedAgain)).toBe('partial')
+  })
+
+  it('QueryObserver stale→fresh and fresh→partial refetches update metadata and notices', async () => {
+    const body = { season: 2026, drivers: [{ points: 42 }] }
+    const sequence: Array<'stale' | 'fresh' | 'partial'> = ['stale', 'fresh', 'partial']
+    let call = 0
+    vi.stubGlobal(
+      'fetch',
+      vi.fn(async () => {
+        const freshness = sequence[Math.min(call, sequence.length - 1)]
+        call += 1
+        return new Response(JSON.stringify(body), {
+          status: 200,
+          headers: {
+            'Content-Type': 'application/json',
+            [DATA_SOURCE_HEADER]: 'openf1',
+            [DATA_FRESHNESS_HEADER]: freshness,
+          },
+        })
+      }),
+    )
+
+    const client = new QueryClient({
+      defaultOptions: {
+        queries: {
+          retry: false,
+          structuralSharing: availabilityAwareStructuralSharing,
+        },
+      },
+    })
+    const observer = new QueryObserver(client, {
+      queryKey: ['availability-observer'],
+      queryFn: () => apiFetch<typeof body>('/api/v1/championship/hub'),
+      staleTime: 0,
+    })
+
+    const notices: Array<string | null> = []
+    const unsub = observer.subscribe((result) => {
+      if (result.data) notices.push(noticeFromResponse(result.data))
+    })
+
+    await observer.refetch()
+    expect(noticeFromResponse(observer.getCurrentResult().data)).toBe('stale')
+    expect(notices[notices.length - 1]).toBe('stale')
+
+    await observer.refetch()
+    expect(observer.getCurrentResult().data).toEqual(body)
+    expect(getResponseAvailability(observer.getCurrentResult().data!)).toEqual({
+      source: 'openf1',
+      freshness: 'fresh',
+    })
+    expect(noticeFromResponse(observer.getCurrentResult().data)).toBeNull()
+    expect(notices[notices.length - 1]).toBeNull()
+
+    await observer.refetch()
+    expect(noticeFromResponse(observer.getCurrentResult().data)).toBe('partial')
+    expect(notices[notices.length - 1]).toBe('partial')
+    expect(call).toBe(3)
+
+    unsub()
+    client.clear()
+  })
 })

tests/issue-76-availability.spec.ts

@@ -184,33 +184,66 @@ async function stubPreSession(page: Page, opts?: { failSessions?: boolean; recov
 }
 
 test.describe('Issue #76 availability / Preview resilience evidence', () => {
-  test('Weekend pre-session keeps shell usable on Preview supplement failure and recovers', async ({
+  test('Weekend pre-session recovers Preview sessions via Retry and keeps distinct notices', async ({
     page,
   }, testInfo) => {
-    await stubPreSession(page, { failSessions: true, recover: true })
+    let sessionCalls = 0
+    let allowSessions = false
+    await stubPreSession(page)
+    await page.unroute('**/api/v1/sessions**')
+    await page.route('**/api/v1/sessions**', async (route) => {
+      const url = new URL(route.request().url())
+      if (url.searchParams.get('meeting_key') === '2') {
+        sessionCalls += 1
+      }
+      if (!allowSessions) {
+        await route.fulfill({
+          status: 500,
+          contentType: 'application/json',
+          body: JSON.stringify({ error: 'API 500: forced sessions failure' }),
+        })
+        return
+      }
+      await route.fulfill({
+        contentType: 'application/json',
+        body: JSON.stringify([
+          {
+            session_key: 21,
+            session_name: 'Practice 1',
+            session_type: 'Practice',
+            meeting_key: 2,
+            date_start: '2026-07-24T09:00:00Z',
+            date_end: '2026-07-24T10:00:00Z',
+            gmt_offset: '',
+          },
+        ]),
+      })
+    })
+
     await page.setViewportSize({ width: 390, height: 844 })
     await page.goto('/')
 
     await expect(page.getByTestId('weekend-pre-session')).toBeVisible()
     await expect(page.getByTestId('wk-pre-head')).toContainText('Hungarian Grand Prix')
     await expect(page.getByTestId('weekend-data-notice')).toContainText(/Partial/i)
-    // Weekend shell owns disclosure — embedded Preview must not stack a second notice.
-    await expect(page.getByTestId('preview-data-notice')).toHaveCount(0)
+    // Shell Partial + Preview championship Stale are distinct — both may show.
+    await expect(page.getByTestId('preview-data-notice')).toContainText(/Stale/i)
     await expect(page.getByTestId('preview-page')).toBeVisible()
     await expect(page.getByTestId('preview-page')).toHaveAttribute('data-meeting-key', '2')
-    // No raw HTTP jargon in the primary Weekend child.
+    await expect(page.getByTestId('preview-sessions-error')).toBeVisible()
     await expect(page.locator('body')).not.toContainText(/API 500|forced sessions failure/i)
-    // Title fight remains usable from the shared championship supplement.
     await expect(page.getByTestId('preview-title-fight-card')).toContainText('VER')
 
-    // Recovery: guarded Retry on the shell notice re-runs context; sessions auto-recover
-    // on React Query retry (recover stub). Shell stays usable either way.
-    const retry = page.getByTestId('weekend-data-notice').getByRole('button', { name: 'Retry' })
+    const failedCalls = sessionCalls
+    expect(failedCalls).toBeGreaterThanOrEqual(1)
+
+    allowSessions = true
+    const retry = page.getByTestId('preview-sessions-retry')
     await expect(retry).toBeEnabled()
     await retry.click()
-    await expect(page.getByTestId('weekend-pre-session')).toBeVisible()
-    await expect(page.getByTestId('preview-page')).toBeVisible()
-    await expect(page.getByTestId('preview-title-fight-card')).toContainText('VER')
+    await expect(page.getByTestId('preview-schedule')).toContainText('Practice 1')
+    await expect(page.getByTestId('preview-sessions-error')).toHaveCount(0)
+    expect(sessionCalls).toBe(failedCalls + 1)
 
     await page.screenshot({
       path: path.join(evidenceDir, `weekend-presession-failure-mobile-${testInfo.project.name}.png`),
@@ -222,9 +255,8 @@ test.describe('Issue #76 availability / Preview resilience evidence', () => {
       path: path.join(evidenceDir, `weekend-presession-partial-desktop-${testInfo.project.name}.png`),
       fullPage: true,
     })
-    // Desktop evidence must also keep a single Partial notice vocabulary.
     await expect(page.getByTestId('weekend-data-notice')).toContainText(/Partial/i)
-    await expect(page.getByTestId('preview-data-notice')).toHaveCount(0)
+    await expect(page.getByTestId('preview-data-notice')).toContainText(/Stale/i)
   })
 
   test('Championship discloses stale metadata above usable standings', async ({ page }, testInfo) => {
@@ -343,6 +375,8 @@ test.describe('Issue #76 availability / Preview resilience evidence', () => {
     await expect(page.getByTestId('briefing-data-notice')).toContainText(/Limited/i)
     await expect(page.getByText('Paddock briefing sample')).toBeVisible()
     await expect(page.locator('body')).not.toContainText(/API 503/i)
+    const retry = page.getByTestId('briefing-data-notice').getByRole('button', { name: 'Retry' })
+    await expect(retry).toBeEnabled()
     await page.screenshot({
       path: path.join(evidenceDir, `briefing-limited-mobile-${testInfo.project.name}.png`),
       fullPage: true,

tests/live-timing.spec.ts

@@ -452,4 +452,28 @@ test.describe('Live Timing (no session)', () => {
     await expect(page.getByTestId('live-feed-health')).toContainText(/reconnecting/i)
     await expect(page.getByTestId('live-feed-health')).not.toContainText(/feed healthy/i)
   })
+
+  test('clears fatal initial error once SSE supplies a live snapshot', async ({ page }) => {
+    await page.route('**/api/v1/live/state', (route) =>
+      route.fulfill({
+        status: 503,
+        contentType: 'application/json',
+        body: JSON.stringify({ error: 'API 503: live state unavailable' }),
+      }),
+    )
+    await page.route('**/api/v1/live/stream', (route) =>
+      route.fulfill({
+        contentType: 'text/event-stream',
+        headers: { 'Cache-Control': 'no-cache' },
+        body: `event: snapshot\ndata: ${JSON.stringify(raceSnapshot)}\n\n`,
+      }),
+    )
+
+    await page.goto('/live')
+    await expect(page.getByText('Timing Tower')).toBeVisible({ timeout: 15_000 })
+    await expect(page.getByTestId('live-initial-error')).toHaveCount(0)
+    await expect(page.getByText(/Live timing unavailable/i)).toHaveCount(0)
+    await expect(page.getByTestId('live-page')).toHaveAttribute('data-phase', /^(live|disconnected)$/)
+    await expect(page.locator('.live-tower')).toContainText('VER')
+  })
 })