fix(#76): report request-scoped data freshness

internal/api/cache.go

@@ -164,8 +164,8 @@ func (c *Cache) Get(key string) ([]byte, bool) {
 	if ttl > 0 {
 		age := time.Since(time.Unix(createdAt, 0))
 		if age > ttl {
-			// Expired — delete and return miss.
+			// Expired entries remain stored so get() can use them as a stale
-			_, _ = c.db.Exec(`DELETE FROM cache WHERE key = ?`, key)
+			// fallback if the live request fails. Prune() owns physical cleanup.
 			atomic.AddInt64(&c.stats.Misses, 1)
 			return nil, false
 		}

internal/api/client.go

@@ -56,6 +56,26 @@ type OpenF1Client struct {
 	staleFlag int32
 }
 
+// Scoped returns a lightweight request-scoped view of the client. Network,
+// pacing and cache resources are shared, while the stale fallback indicator is
+// deliberately not shared. Web handlers use this view so a stale fallback in
+// one concurrent HTTP request can never mark an unrelated response as stale.
+//
+// The legacy client-wide stale flag remains available for the TUI, whose loads
+// are intentionally aggregated into one navigation-level notice.
+func (c *OpenF1Client) Scoped() *OpenF1Client {
+	if c == nil {
+		return nil
+	}
+	return &OpenF1Client{
+		url:        c.url,
+		apiKey:     c.apiKey,
+		httpClient: c.httpClient,
+		cache:      c.cache,
+		pacer:      c.pacer,
+	}
+}
+
 func NewOpenF1Client(url string, timeout time.Duration) *OpenF1Client {
 	return &OpenF1Client{
 		url:        url,

internal/api/freshness_test.go

@@ -0,0 +1,123 @@
+package api
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func expireCacheEntry(t *testing.T, c *OpenF1Client, key string) {
+	t.Helper()
+	if _, err := c.cache.db.Exec(`UPDATE cache SET created_at = ? WHERE key = ?`, time.Now().Add(-48*time.Hour).Unix(), key); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestScopedClientReportsStaleFallbackWithoutMutatingParent(t *testing.T) {
+	year := time.Now().Year()
+	var fail atomic.Bool
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if fail.Load() {
+			http.Error(w, "unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = fmt.Fprintf(w, `[{
+			"meeting_key": 1,
+			"meeting_name": "British Grand Prix",
+			"year": %d
+		}]`, year)
+	}))
+	defer upstream.Close()
+
+	client := NewOpenF1Client(upstream.URL, time.Second)
+	defer client.Close()
+	client.pacer.interval = 0
+	key := fmt.Sprintf("%s/v1/meetings?year=%d", upstream.URL, year)
+	_, _ = client.cache.db.Exec(`DELETE FROM cache WHERE key = ?`, key)
+	defer func() { _, _ = client.cache.db.Exec(`DELETE FROM cache WHERE key = ?`, key) }()
+
+	if _, err := client.GetMeetingsForYear(year); err != nil {
+		t.Fatalf("prime cache: %v", err)
+	}
+	expireCacheEntry(t, client, key)
+	fail.Store(true)
+
+	scoped := client.Scoped()
+	meetings, err := scoped.GetMeetingsForYear(year)
+	if err != nil || len(meetings) != 1 {
+		t.Fatalf("stale fallback = (%+v, %v)", meetings, err)
+	}
+	if !scoped.LastResponseWasStale() {
+		t.Fatal("scoped request did not report its stale fallback")
+	}
+	if client.LastResponseWasStale() {
+		t.Fatal("request-scoped fallback leaked into the parent client")
+	}
+}
+
+func TestScopedClientsDoNotLeakFreshnessAcrossConcurrentRequests(t *testing.T) {
+	year := time.Now().Year()
+	staleStarted := make(chan struct{})
+	releaseStale := make(chan struct{})
+	var failMeetings atomic.Bool
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/v1/meetings":
+			if failMeetings.Load() {
+				close(staleStarted)
+				<-releaseStale
+				http.Error(w, "unavailable", http.StatusServiceUnavailable)
+				return
+			}
+			_, _ = fmt.Fprintf(w, `[{"meeting_key":1,"meeting_name":"British Grand Prix","year":%d}]`, year)
+		case "/v1/sessions":
+			_, _ = w.Write([]byte(`[{"session_key":11,"meeting_key":2,"session_name":"Race"}]`))
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer upstream.Close()
+
+	client := NewOpenF1Client(upstream.URL, 2*time.Second)
+	defer client.Close()
+	client.pacer.interval = 0
+	meetingKey := fmt.Sprintf("%s/v1/meetings?year=%d", upstream.URL, year)
+	sessionKey := upstream.URL + "/v1/sessions?meeting_key=2"
+	_, _ = client.cache.db.Exec(`DELETE FROM cache WHERE key IN (?, ?)`, meetingKey, sessionKey)
+	defer func() { _, _ = client.cache.db.Exec(`DELETE FROM cache WHERE key IN (?, ?)`, meetingKey, sessionKey) }()
+	if _, err := client.GetMeetingsForYear(year); err != nil {
+		t.Fatal(err)
+	}
+	expireCacheEntry(t, client, meetingKey)
+	failMeetings.Store(true)
+
+	staleClient := client.Scoped()
+	staleDone := make(chan error, 1)
+	go func() {
+		_, err := staleClient.GetMeetingsForYear(year)
+		staleDone <- err
+	}()
+	<-staleStarted
+
+	freshClient := client.Scoped()
+	if _, err := freshClient.GetSessionsForMeeting(2); err != nil {
+		t.Fatalf("fresh concurrent request: %v", err)
+	}
+	if freshClient.LastResponseWasStale() {
+		t.Fatal("fresh request inherited concurrent request's stale state")
+	}
+	close(releaseStale)
+	if err := <-staleDone; err != nil {
+		t.Fatalf("stale request: %v", err)
+	}
+	if !staleClient.LastResponseWasStale() {
+		t.Fatal("stale request lost its own freshness state")
+	}
+	if freshClient.LastResponseWasStale() || client.LastResponseWasStale() {
+		t.Fatal("stale state leaked after concurrent requests completed")
+	}
+}

internal/query/context.go

@@ -40,6 +40,7 @@ type LiveEvidence struct {
 
 // ContextAvailability is structured source state for a referenced session.
 type ContextAvailability struct {
+	Source        string   `json:"source"`
 	Schedule      string   `json:"schedule"`
 	LiveTransport string   `json:"live_transport"`
 	LiveSession   string   `json:"live_session"`
@@ -298,21 +299,28 @@ func meetingModelByKey(meetings []store.Meeting, key int) *models.Meeting {
 func sessionRef(c contextCandidate, evidence LiveEvidence, now time.Time) *ContextSession {
 	session := sessionToModel(c.session)
 	meeting := meetingToModel(c.meeting)
-	availability := ContextAvailability{Schedule: "available", LiveSession: "inactive", Archive: "unavailable", Freshness: "fresh", Limitations: []string{}}
+	// Schedule and analysis are domain-store facts. Without an ingestion
+	// timestamp the resolver cannot honestly call them network-fresh, so local
+	// is the baseline freshness vocabulary exposed to clients.
+	availability := ContextAvailability{Source: "local", Schedule: "available", LiveSession: "inactive", Archive: "unavailable", Freshness: "local", Limitations: []string{}}
 	availability.LiveTransport = "unknown"
 	if c.session.SessionKey == 0 {
 		availability.Schedule = "unavailable"
 		availability.Limitations = append(availability.Limitations, "schedule_identity_unmatched")
 	}
 	if evidence.Active && liveMatches(evidence, c.meeting, c.session) {
+		availability.Source = "mixed"
 		availability.LiveTransport = "connected"
 		availability.LiveSession = "active"
+		availability.Freshness = "live"
 		if !evidence.ObservedAt.IsZero() {
 			availability.ObservedAt = evidence.ObservedAt.Format(time.RFC3339)
 		}
 	}
 	if c.archived {
+		availability.Source = "mixed"
 		availability.Archive = "available"
+		availability.Freshness = "archive"
 		if !evidence.ObservedAt.IsZero() {
 			availability.ObservedAt = evidence.ObservedAt.Format(time.RFC3339)
 		}
@@ -326,6 +334,12 @@ func sessionRef(c contextCandidate, evidence LiveEvidence, now time.Time) *Conte
 	} else {
 		availability.LocalAnalysis = "pending"
 	}
+	if availability.LocalAnalysis == "partial" && availability.Freshness == "local" {
+		availability.Freshness = "partial"
+	}
+	if c.session.SessionKey == 0 && availability.LiveSession == "active" {
+		availability.Source = "fia"
+	}
 	return &ContextSession{Session: session, Meeting: &meeting, Availability: availability}
 }
 

internal/query/context_test.go

@@ -160,6 +160,54 @@ func TestResolveWeekendContextPassedTimeDoesNotCompleteSession(t *testing.T) {
 	}
 }
 
+func TestResolveWeekendContextAvailabilityUsesTruthfulSources(t *testing.T) {
+	now, _ := time.Parse(time.RFC3339, "2026-07-05T18:00:00Z")
+	svc := contextService(t, now)
+	addContextMeeting(t, svc, 1, "British Grand Prix", "2026-07-03T00:00:00Z", "2026-07-05T16:00:00Z", false)
+	addContextSession(t, svc, 11, 1, "Race", "2026-07-05T14:00:00Z", "2026-07-05T16:00:00Z", false)
+	// Results without laps/stints/positions are meaningful but incomplete local
+	// analysis, so they must not be labelled universally fresh.
+	completeContextSession(t, svc, 11, 1)
+	addContextMeeting(t, svc, 2, "Belgian Grand Prix", "2026-07-17T00:00:00Z", "2026-07-19T16:00:00Z", false)
+	addContextSession(t, svc, 21, 2, "Practice 1", "2026-07-17T09:00:00Z", "2026-07-17T10:00:00Z", false)
+	addContextSession(t, svc, 22, 2, "Race", "2026-07-19T14:00:00Z", "2026-07-19T16:00:00Z", false)
+
+	local, err := svc.ResolveWeekendContext(LiveEvidence{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := local.PreviousCompletedSession.Availability; got.Source != "local" || got.Freshness != "partial" || got.LocalAnalysis != "partial" {
+		t.Fatalf("partial local availability = %+v", got)
+	}
+	if got := local.NextSession.Availability; got.Source != "local" || got.Freshness != "local" {
+		t.Fatalf("future local availability = %+v", got)
+	}
+
+	liveContext, err := svc.ResolveWeekendContext(LiveEvidence{Active: true, MeetingName: "Belgian Grand Prix", CircuitName: "Belgian Grand Prix", SessionName: "Practice 1", SessionType: "Practice 1", ObservedAt: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := liveContext.ActiveSession.Availability; got.Source != "mixed" || got.Freshness != "live" || got.LiveSession != "active" {
+		t.Fatalf("FIA + local availability = %+v", got)
+	}
+
+	archiveContext, err := svc.ResolveWeekendContext(LiveEvidence{Final: true, MeetingName: "British Grand Prix", CircuitName: "British Grand Prix", SessionName: "Race", SessionType: "Race", ObservedAt: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := archiveContext.PreviousCompletedSession.Availability; got.Source != "mixed" || got.Freshness != "archive" || got.Archive != "available" {
+		t.Fatalf("FIA archive + local availability = %+v", got)
+	}
+
+	synthetic, err := svc.ResolveWeekendContext(LiveEvidence{Active: true, MeetingName: "Unscheduled Grand Prix", SessionName: "Race", SessionType: "Race", ObservedAt: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := synthetic.ActiveSession.Availability; got.Source != "fia" || got.Freshness != "live" || got.Schedule != "unavailable" {
+		t.Fatalf("synthetic FIA availability = %+v", got)
+	}
+}
+
 func TestResolveWeekendContextNeverUsesFutureAnalysis(t *testing.T) {
 	now, _ := time.Parse(time.RFC3339, "2026-07-01T12:00:00Z")
 	svc := contextService(t, now)

internal/web/api.go

@@ -16,6 +16,7 @@ import (
 
 	readability "codeberg.org/readeck/go-readability/v2"
 
+	"github.com/AmanTahiliani/box-box/internal/api"
 	"github.com/AmanTahiliani/box-box/internal/models"
 	"github.com/AmanTahiliani/box-box/internal/query"
 )
@@ -43,6 +44,7 @@ func (s *Server) handleMeetings(w http.ResponseWriter, r *http.Request) {
 
 	switch parseSourceMode(r) {
 	case sourceLocal:
+		markLocalResponse(w, false)
 		if !s.hasLocalQuery() {
 			writeJSON(w, []models.Meeting{})
 			return
@@ -62,17 +64,20 @@ func (s *Server) handleMeetings(w http.ResponseWriter, r *http.Request) {
 				return
 			}
 			if len(meetings) > 0 {
+				markLocalResponse(w, false)
 				writeJSON(w, meetings)
 				return
 			}
 		}
 	}
 
-	meetings, err := s.client.GetMeetingsForYear(year)
+	client := s.client.Scoped()
+	meetings, err := client.GetMeetingsForYear(year)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, meetings)
 }
 
@@ -87,6 +92,7 @@ func (s *Server) handleSessions(w http.ResponseWriter, r *http.Request) {
 
 	switch parseSourceMode(r) {
 	case sourceLocal:
+		markLocalResponse(w, false)
 		if !s.hasLocalQuery() {
 			writeJSON(w, []models.Session{})
 			return
@@ -106,23 +112,27 @@ func (s *Server) handleSessions(w http.ResponseWriter, r *http.Request) {
 				return
 			}
 			if len(sessions) > 0 {
+				markLocalResponse(w, false)
 				writeJSON(w, sessions)
 				return
 			}
 		}
 	}
 
-	sessions, err := s.client.GetSessionsForMeeting(meetingKey)
+	client := s.client.Scoped()
+	sessions, err := client.GetSessionsForMeeting(meetingKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, sessions)
 }
 
 // --- /api/v1/news ---
 
 func (s *Server) handleNews(w http.ResponseWriter, r *http.Request) {
+	markLocalResponse(w, false)
 	if !s.hasLocalQuery() {
 		writeJSON(w, []query.NewsItem{})
 		return
@@ -223,6 +233,7 @@ func (s *Server) handleDrivers(w http.ResponseWriter, r *http.Request) {
 
 	switch parseSourceMode(r) {
 	case sourceLocal:
+		markLocalResponse(w, false)
 		if !s.hasLocalQuery() {
 			writeJSON(w, []models.Driver{})
 			return
@@ -242,6 +253,7 @@ func (s *Server) handleDrivers(w http.ResponseWriter, r *http.Request) {
 		if s.hasLocalQuery() {
 			drivers, err := s.query.ListDrivers(sessionKey)
 			if err == nil && len(drivers) > 0 {
+				markLocalResponse(w, false)
 				writeJSON(w, drivers)
 				return
 			}
@@ -252,11 +264,13 @@ func (s *Server) handleDrivers(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	drivers, err := s.client.GetDriversForSession(sessionKey)
+	client := s.client.Scoped()
+	drivers, err := client.GetDriversForSession(sessionKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, drivers)
 }
 
@@ -279,6 +293,7 @@ func (s *Server) handleResults(w http.ResponseWriter, r *http.Request) {
 
 	switch parseSourceMode(r) {
 	case sourceLocal:
+		markLocalResponse(w, false)
 		if !s.hasLocalQuery() {
 			writeJSON(w, []resultWithDriver{})
 			return
@@ -294,6 +309,7 @@ func (s *Server) handleResults(w http.ResponseWriter, r *http.Request) {
 		if s.hasLocalQuery() {
 			results, err := s.query.ListResults(sessionKey)
 			if err == nil && len(results) > 0 {
+				markLocalResponse(w, false)
 				writeJSON(w, enrichedResultsToAPI(results))
 				return
 			}
@@ -310,13 +326,14 @@ func (s *Server) handleResults(w http.ResponseWriter, r *http.Request) {
 		resultsErr error
 		wg         sync.WaitGroup
 	)
+	client := s.client.Scoped()
 	wg.Add(2)
-	go func() { defer wg.Done(); results, resultsErr = s.client.GetSessionResult(sessionKey) }()
+	go func() { defer wg.Done(); results, resultsErr = client.GetSessionResult(sessionKey) }()
-	go func() { defer wg.Done(); drivers, _ = s.client.GetDriversForSession(sessionKey) }()
+	go func() { defer wg.Done(); drivers, _ = client.GetDriversForSession(sessionKey) }()
 	wg.Wait()
 
 	if resultsErr != nil {
-		writeError(w, resultsErr, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, resultsErr, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
 
@@ -332,6 +349,7 @@ func (s *Server) handleResults(w http.ResponseWriter, r *http.Request) {
 		}
 		enriched = append(enriched, e)
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, enriched)
 }
 
@@ -354,6 +372,7 @@ func (s *Server) handleGrid(w http.ResponseWriter, r *http.Request) {
 
 	switch parseSourceMode(r) {
 	case sourceLocal:
+		markLocalResponse(w, false)
 		if !s.hasLocalQuery() {
 			writeJSON(w, []gridWithDriver{})
 			return
@@ -369,6 +388,7 @@ func (s *Server) handleGrid(w http.ResponseWriter, r *http.Request) {
 		if s.hasLocalQuery() {
 			grid, err := s.query.ListStartingGrid(sessionKey)
 			if err == nil && len(grid) > 0 {
+				markLocalResponse(w, false)
 				writeJSON(w, enrichedGridToAPI(grid))
 				return
 			}
@@ -385,13 +405,14 @@ func (s *Server) handleGrid(w http.ResponseWriter, r *http.Request) {
 		gridErr error
 		wg      sync.WaitGroup
 	)
+	client := s.client.Scoped()
 	wg.Add(2)
-	go func() { defer wg.Done(); grid, gridErr = s.client.GetStartingGrid(sessionKey) }()
+	go func() { defer wg.Done(); grid, gridErr = client.GetStartingGrid(sessionKey) }()
-	go func() { defer wg.Done(); drivers, _ = s.client.GetDriversForSession(sessionKey) }()
+	go func() { defer wg.Done(); drivers, _ = client.GetDriversForSession(sessionKey) }()
 	wg.Wait()
 
 	if gridErr != nil {
-		writeError(w, gridErr, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, gridErr, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
 
@@ -407,6 +428,7 @@ func (s *Server) handleGrid(w http.ResponseWriter, r *http.Request) {
 		}
 		enriched = append(enriched, e)
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, enriched)
 }
 
@@ -419,26 +441,29 @@ func (s *Server) handleLaps(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	client := s.client.Scoped()
 	if dnStr := r.URL.Query().Get("driver_number"); dnStr != "" {
 		driverNumber, err := strconv.Atoi(dnStr)
 		if err != nil || driverNumber == 0 {
 			http.Error(w, "invalid driver_number", http.StatusBadRequest)
 			return
 		}
-		laps, err := s.client.GetLapsForDriver(sessionKey, driverNumber)
+		laps, err := client.GetLapsForDriver(sessionKey, driverNumber)
 		if err != nil {
-			writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+			writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 			return
 		}
+		markOpenF1Response(w, client)
 		writeJSON(w, laps)
 		return
 	}
 
-	laps, err := s.client.GetLapsForSession(sessionKey)
+	laps, err := client.GetLapsForSession(sessionKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, laps)
 }
 
@@ -450,11 +475,13 @@ func (s *Server) handleWeather(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "session_key required", http.StatusBadRequest)
 		return
 	}
-	weather, err := s.client.GetWeather(sessionKey)
+	client := s.client.Scoped()
+	weather, err := client.GetWeather(sessionKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, weather)
 }
 
@@ -466,11 +493,13 @@ func (s *Server) handleRaceControl(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "session_key required", http.StatusBadRequest)
 		return
 	}
-	rc, err := s.client.GetRaceControl(sessionKey)
+	client := s.client.Scoped()
+	rc, err := client.GetRaceControl(sessionKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, rc)
 }
 
@@ -487,11 +516,13 @@ func (s *Server) handleTelemetry(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "driver_number required", http.StatusBadRequest)
 		return
 	}
-	carData, err := s.client.GetCarData(sessionKey, driverNumber)
+	client := s.client.Scoped()
+	carData, err := client.GetCarData(sessionKey, driverNumber)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, carData)
 }
 
@@ -503,11 +534,13 @@ func (s *Server) handleOvertakes(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "session_key required", http.StatusBadRequest)
 		return
 	}
-	overtakes, err := s.client.GetOvertakesForSession(sessionKey)
+	client := s.client.Scoped()
+	overtakes, err := client.GetOvertakesForSession(sessionKey)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, overtakes)
 }
 
@@ -524,11 +557,13 @@ func (s *Server) handleTeamRadio(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "driver_number required", http.StatusBadRequest)
 		return
 	}
-	radios, err := s.client.GetTeamRadio(sessionKey, driverNumber)
+	client := s.client.Scoped()
+	radios, err := client.GetTeamRadio(sessionKey, driverNumber)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, radios)
 }
 
@@ -547,23 +582,25 @@ func (s *Server) handleChampionshipDrivers(w http.ResponseWriter, r *http.Reques
 	if year == 0 {
 		year = time.Now().Year()
 	}
-	champ, err := s.client.GetDriverChampionshipForYear(year)
+	client := s.client.Scoped()
+	champ, err := client.GetDriverChampionshipForYear(year)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
 	if len(champ) == 0 {
+		markOpenF1Response(w, client)
 		writeJSON(w, []any{})
 		return
 	}
 
-	drivers, _ := s.client.GetDriversForSession(champ[0].SessionKey)
+	drivers, _ := client.GetDriversForSession(champ[0].SessionKey)
 	driverMap := buildDriverMapFirst(drivers)
 
 	enriched := make([]champDriverWithInfo, 0, len(champ))
 	for _, c := range champ {
 		e := champDriverWithInfo{ChampionshipDriver: c}
-		d, ok := s.championshipDriverInfo(c.SessionKey, c.DriverNumber, driverMap)
+		d, ok := championshipDriverInfo(client, c.SessionKey, c.DriverNumber, driverMap)
 		if ok {
 			e.NameAcronym = d.NameAcronym
 			e.FullName = d.FullName
@@ -572,11 +609,12 @@ func (s *Server) handleChampionshipDrivers(w http.ResponseWriter, r *http.Reques
 		}
 		enriched = append(enriched, e)
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, enriched)
 }
 
-func (s *Server) championshipDriverInfo(sessionKey, driverNumber int, fallback map[int]models.Driver) (models.Driver, bool) {
+func championshipDriverInfo(client *api.OpenF1Client, sessionKey, driverNumber int, fallback map[int]models.Driver) (models.Driver, bool) {
-	if d, err := s.client.GetDriver(sessionKey, driverNumber); err == nil && d != nil {
+	if d, err := client.GetDriver(sessionKey, driverNumber); err == nil && d != nil {
 		return *d, true
 	}
 	d, ok := fallback[driverNumber]
@@ -590,11 +628,13 @@ func (s *Server) handleChampionshipTeams(w http.ResponseWriter, r *http.Request)
 	if year == 0 {
 		year = time.Now().Year()
 	}
-	teams, err := s.client.GetTeamChampionshipForYear(year)
+	client := s.client.Scoped()
+	teams, err := client.GetTeamChampionshipForYear(year)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, teams)
 }
 
@@ -672,6 +712,8 @@ func champHubTTL(year int, now time.Time) time.Duration {
 
 type champHubEntry struct {
 	resp      champHubResponse
+	source    string
+	freshness string
 	expires   time.Time
 }
 
@@ -693,12 +735,26 @@ func (c *champHubCache) get(year int, now time.Time) (champHubResponse, bool) {
 }
 
 func (c *champHubCache) put(year int, resp champHubResponse, now time.Time, ttl time.Duration) {
+	c.putWithMetadata(year, resp, "local", "local", now, ttl)
+}
+
+func (c *champHubCache) getWithMetadata(year int, now time.Time) (champHubResponse, string, string, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	e, ok := c.entries[year]
+	if !ok || now.After(e.expires) {
+		return champHubResponse{}, "", "", false
+	}
+	return e.resp, e.source, e.freshness, true
+}
+
+func (c *champHubCache) putWithMetadata(year int, resp champHubResponse, source, freshness string, now time.Time, ttl time.Duration) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	if c.entries == nil {
 		c.entries = map[int]champHubEntry{}
 	}
-	c.entries[year] = champHubEntry{resp: resp, expires: now.Add(ttl)}
+	c.entries[year] = champHubEntry{resp: resp, source: source, freshness: freshness, expires: now.Add(ttl)}
 }
 
 // fetchMeetingRaces fans fetch out across meetings with bounded concurrency.
@@ -740,13 +796,6 @@ func (s *Server) handleChampionshipHub(w http.ResponseWriter, r *http.Request) {
 	}
 	mode := parseSourceMode(r)
 
-	if mode != sourceLocal {
-		if resp, ok := s.hubCache.get(year, time.Now()); ok {
-			writeJSON(w, resp)
-			return
-		}
-	}
-
 	if mode == sourceLocal || mode == sourceAuto {
 		resp, ok, err := s.localChampionshipHub(year)
 		if err != nil {
@@ -754,21 +803,33 @@ func (s *Server) handleChampionshipHub(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		if ok {
-			s.hubCache.put(year, resp, time.Now(), champHubTTL(year, time.Now()))
+			s.hubCache.putWithMetadata(year, resp, "local", "local", time.Now(), champHubTTL(year, time.Now()))
+			markLocalResponse(w, false)
 			writeJSON(w, resp)
 			return
 		}
 		if mode == sourceLocal {
+			markLocalResponse(w, false)
 			writeJSON(w, resp)
 			return
 		}
 	}
 
-	resp, err := s.openF1ChampionshipHub(year)
+	// At this point an auto request has no usable domain aggregate and an
-	if err != nil {
+	// explicit OpenF1 request must not be satisfied by a local cache entry.
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+	if resp, source, freshness, ok := s.hubCache.getWithMetadata(year, time.Now()); ok && source == "openf1" {
+		markDataResponse(w, source, freshness)
+		writeJSON(w, resp)
 		return
 	}
+
+	client := s.client.Scoped()
+	resp, incomplete, err := s.openF1ChampionshipHub(client, year)
+	if err != nil {
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
+		return
+	}
+	markOpenF1AggregateResponse(w, client, incomplete)
 	writeJSON(w, resp)
 }
 
@@ -797,25 +858,26 @@ func (s *Server) localChampionshipHub(year int) (champHubResponse, bool, error)
 	return aggregateChampionshipHub(year, races, inputs.Champ, inputs.Teams, inputs.DriverMap), true, nil
 }
 
-func (s *Server) openF1ChampionshipHub(year int) (champHubResponse, error) {
+func (s *Server) openF1ChampionshipHub(client *api.OpenF1Client, year int) (champHubResponse, bool, error) {
-	champ, err := s.client.GetDriverChampionshipForYear(year)
+	champ, err := client.GetDriverChampionshipForYear(year)
 	if err != nil {
-		return champHubResponse{}, err
+		return champHubResponse{}, false, err
 	}
 	if len(champ) == 0 {
-		return champHubResponse{Season: year, RoundLabels: []string{}, Drivers: []champHubDriver{}, Teams: []champHubTeam{}}, nil
+		return champHubResponse{Season: year, RoundLabels: []string{}, Drivers: []champHubDriver{}, Teams: []champHubTeam{}}, false, nil
 	}
-	teams, _ := s.client.GetTeamChampionshipForYear(year)
+	teams, teamsErr := client.GetTeamChampionshipForYear(year)
 
 	driverInfo := map[int]models.Driver{}
-	if ds, derr := s.client.GetDriversForSession(champ[0].SessionKey); derr == nil {
+	if ds, derr := client.GetDriversForSession(champ[0].SessionKey); derr == nil {
 		driverInfo = buildDriverMapFirst(ds)
 	}
 
-	races, incomplete, err := s.fetchSeasonRaces(year)
+	races, incomplete, err := fetchSeasonRaces(client, year)
 	if err != nil {
-		return champHubResponse{}, err
+		return champHubResponse{}, false, err
 	}
+	incomplete = incomplete || teamsErr != nil
 
 	resp := aggregateChampionshipHub(year, races, champ, teams, driverInfo)
 	ttl := champHubTTL(year, time.Now())
@@ -825,16 +887,22 @@ func (s *Server) openF1ChampionshipHub(year int) (champHubResponse, error) {
 		// so a partial view of the season doesn't stick around for the full TTL.
 		ttl = champHubIncompleteTTL
 	}
-	s.hubCache.put(year, resp, time.Now(), ttl)
+	freshness := "fresh"
-	return resp, nil
+	if client.LastResponseWasStale() {
+		freshness = "stale"
+	} else if incomplete {
+		freshness = "partial"
+	}
+	s.hubCache.putWithMetadata(year, resp, "openf1", freshness, time.Now(), ttl)
+	return resp, incomplete, nil
 }
 
 // fetchSeasonRaces returns a season's GP meetings in date order, each bundled
 // with its race results and starting grid fetched from OpenF1. incomplete
 // reports whether any per-meeting fetch failed, so callers can avoid caching a
 // partial view of the season for long.
-func (s *Server) fetchSeasonRaces(year int) (races []meetingRace, incomplete bool, err error) {
+func fetchSeasonRaces(client *api.OpenF1Client, year int) (races []meetingRace, incomplete bool, err error) {
-	meetings, err := s.client.GetMeetingsForYear(year)
+	meetings, err := client.GetMeetingsForYear(year)
 	if err != nil {
 		return nil, false, err
 	}
@@ -842,7 +910,7 @@ func (s *Server) fetchSeasonRaces(year int) (races []meetingRace, incomplete boo
 
 	var failed atomic.Bool
 	races = fetchMeetingRaces(meetings, champHubWorkers, func(m models.Meeting) (meetingRace, bool) {
-		sessions, serr := s.client.GetSessionsForMeeting(int(m.MeetingKey))
+		sessions, serr := client.GetSessionsForMeeting(int(m.MeetingKey))
 		if serr != nil {
 			failed.Store(true)
 			return meetingRace{}, false
@@ -857,8 +925,8 @@ func (s *Server) fetchSeasonRaces(year int) (races []meetingRace, incomplete boo
 		if raceKey == 0 {
 			return meetingRace{}, false // not a GP meeting (e.g. pre-season testing)
 		}
-		results, rerr := s.client.GetSessionResult(raceKey)
+		results, rerr := client.GetSessionResult(raceKey)
-		grid, gerr := s.client.GetStartingGrid(raceKey)
+		grid, gerr := client.GetStartingGrid(raceKey)
 		if rerr != nil || gerr != nil {
 			failed.Store(true)
 		}
@@ -1077,6 +1145,7 @@ type trackOutlineResponse struct {
 }
 
 func (s *Server) handleTrackOutline(w http.ResponseWriter, r *http.Request) {
+	markLocalResponse(w, false)
 	year, _ := strconv.Atoi(r.URL.Query().Get("year"))
 	if year == 0 {
 		year = time.Now().Year()
@@ -1283,12 +1352,13 @@ func (s *Server) handleStrategy(w http.ResponseWriter, r *http.Request) {
 		resErr    error
 		wg        sync.WaitGroup
 	)
+	client := s.client.Scoped()
 	wg.Add(5)
-	go func() { defer wg.Done(); stints, stintsErr = s.client.GetStintsForSession(sessionKey) }()
+	go func() { defer wg.Done(); stints, stintsErr = client.GetStintsForSession(sessionKey) }()
-	go func() { defer wg.Done(); pits, pitsErr = s.client.GetPitStopsForSession(sessionKey) }()
+	go func() { defer wg.Done(); pits, pitsErr = client.GetPitStopsForSession(sessionKey) }()
-	go func() { defer wg.Done(); results, resErr = s.client.GetSessionResult(sessionKey) }()
+	go func() { defer wg.Done(); results, resErr = client.GetSessionResult(sessionKey) }()
-	go func() { defer wg.Done(); drivers, _ = s.client.GetDriversForSession(sessionKey) }()
+	go func() { defer wg.Done(); drivers, _ = client.GetDriversForSession(sessionKey) }()
-	go func() { defer wg.Done(); rc, _ = s.client.GetRaceControl(sessionKey) }()
+	go func() { defer wg.Done(); rc, _ = client.GetRaceControl(sessionKey) }()
 	wg.Wait()
 
 	if stintsErr != nil || pitsErr != nil || resErr != nil {
@@ -1299,12 +1369,13 @@ func (s *Server) handleStrategy(w http.ResponseWriter, r *http.Request) {
 		if e == nil {
 			e = resErr
 		}
-		writeError(w, e, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, e, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
 
 	// Non-race sessions have no stints.
 	if len(stints) == 0 {
+		markOpenF1Response(w, client)
 		writeJSON(w, map[string]any{"note": "Not applicable", "drivers": []any{}})
 		return
 	}
@@ -1396,6 +1467,7 @@ func (s *Server) handleStrategy(w http.ResponseWriter, r *http.Request) {
 		return pi < pj
 	})
 
+	markOpenF1Response(w, client)
 	writeJSON(w, strategyResponse{
 		SessionKey: sessionKey,
 		TotalLaps:  totalLaps,
@@ -1497,14 +1569,15 @@ func (s *Server) handleLapsComparison(w http.ResponseWriter, r *http.Request) {
 		rc      []models.RaceControl
 		wg      sync.WaitGroup
 	)
+	client := s.client.Scoped()
 	wg.Add(4)
-	go func() { defer wg.Done(); allLaps, _ = s.client.GetLapsForSession(sessionKey) }()
+	go func() { defer wg.Done(); allLaps, _ = client.GetLapsForSession(sessionKey) }()
-	go func() { defer wg.Done(); stints, _ = s.client.GetStintsForSession(sessionKey) }()
+	go func() { defer wg.Done(); stints, _ = client.GetStintsForSession(sessionKey) }()
-	go func() { defer wg.Done(); pits, _ = s.client.GetPitStopsForSession(sessionKey) }()
+	go func() { defer wg.Done(); pits, _ = client.GetPitStopsForSession(sessionKey) }()
-	go func() { defer wg.Done(); rc, _ = s.client.GetRaceControl(sessionKey) }()
+	go func() { defer wg.Done(); rc, _ = client.GetRaceControl(sessionKey) }()
 	wg.Wait()
 
-	allDrivers, _ := s.client.GetDriversForSession(sessionKey)
+	allDrivers, _ := client.GetDriversForSession(sessionKey)
 	driverMap := buildDriverMap(allDrivers)
 
 	// If no filter, default to first 3 unique driver numbers from lap data.
@@ -1558,6 +1631,7 @@ func (s *Server) handleLapsComparison(w http.ResponseWriter, r *http.Request) {
 		compDrivers = append(compDrivers, cd)
 	}
 
+	markOpenF1Response(w, client)
 	writeJSON(w, lapsComparisonResponse{
 		SessionKey: sessionKey,
 		SCPeriods:  extractSCPeriods(rc),

internal/web/context.go

@@ -9,6 +9,7 @@ import (
 )
 
 func (s *Server) handleWeekendContext(w http.ResponseWriter, _ *http.Request) {
+	markLocalResponse(w, false)
 	if !s.hasLocalQuery() {
 		writeJSON(w, query.WeekendContext{TemporalState: query.TemporalNoSeason})
 		return
@@ -29,6 +30,12 @@ func (s *Server) handleWeekendContext(w http.ResponseWriter, _ *http.Request) {
 		writeError(w, err, http.StatusInternalServerError, false)
 		return
 	}
+	for _, ref := range []*query.ContextSession{context.ActiveSession, context.PreviousCompletedSession, context.DefaultAnalysisSession, context.NextSession} {
+		if ref != nil && ref.Availability.Freshness != "local" {
+			markDataResponse(w, ref.Availability.Source, ref.Availability.Freshness)
+			break
+		}
+	}
 	writeJSON(w, context)
 }
 

internal/web/context_test.go

@@ -76,6 +76,12 @@ func TestWeekendContextHandlerUsesLiveHubIdentityWithoutOpenF1(t *testing.T) {
 	if got.ActiveSession.Availability.LiveTransport != "connected" || got.ActiveSession.Availability.LiveSession != "active" {
 		t.Fatalf("availability = %+v", got.ActiveSession.Availability)
 	}
+	if got.ActiveSession.Availability.Source != "mixed" || got.ActiveSession.Availability.Freshness != "live" {
+		t.Fatalf("live source/freshness = %+v", got.ActiveSession.Availability)
+	}
+	if rr.Header().Get(dataSourceHeader) != "mixed" || rr.Header().Get(dataFreshnessHeader) != "live" {
+		t.Fatalf("response source/freshness = %q/%q", rr.Header().Get(dataSourceHeader), rr.Header().Get(dataFreshnessHeader))
+	}
 }
 
 func TestWeekendContextHandlerUsesTerminalArchiveAsCompletionEvidence(t *testing.T) {
@@ -94,6 +100,12 @@ func TestWeekendContextHandlerUsesTerminalArchiveAsCompletionEvidence(t *testing
 	if got.PreviousCompletedSession == nil || got.PreviousCompletedSession.Availability.Archive != "available" {
 		t.Fatalf("archive context = %+v", got)
 	}
+	if got.PreviousCompletedSession.Availability.Source != "mixed" || got.PreviousCompletedSession.Availability.Freshness != "archive" {
+		t.Fatalf("archive source/freshness = %+v", got.PreviousCompletedSession.Availability)
+	}
+	if rr.Header().Get(dataSourceHeader) != "mixed" || rr.Header().Get(dataFreshnessHeader) != "archive" {
+		t.Fatalf("archive response source/freshness = %q/%q", rr.Header().Get(dataSourceHeader), rr.Header().Get(dataFreshnessHeader))
+	}
 	if got.DefaultAnalysisSession != nil {
 		t.Fatal("archive-only session must not become local default analysis")
 	}

internal/web/driversummary.go

@@ -6,6 +6,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/AmanTahiliani/box-box/internal/api"
 	"github.com/AmanTahiliani/box-box/internal/models"
 )
 
@@ -78,6 +79,7 @@ func (s *Server) handleDriverSummary(w http.ResponseWriter, r *http.Request) {
 	if r.URL.Query().Get("source") == "" {
 		mode = sourceAuto
 	}
+	client := s.client.Scoped()
 
 	if mode == sourceLocal || mode == sourceAuto {
 		resp, sessionKey, ok, lerr := s.localDriverSummary(year, driverNumber)
@@ -87,7 +89,15 @@ func (s *Server) handleDriverSummary(w http.ResponseWriter, r *http.Request) {
 		}
 		if ok {
 			if mode != sourceLocal {
-				s.tryEnrichDriverSummary(&resp, sessionKey)
+				tryEnrichDriverSummary(client, &resp, sessionKey)
+			}
+			switch resp.Enrichment {
+			case "full":
+				markMixedResponse(w, client, false)
+			case "limited":
+				markDataResponse(w, "local", "limited")
+			default:
+				markLocalResponse(w, false)
 			}
 			writeJSON(w, resp)
 			return
@@ -98,15 +108,16 @@ func (s *Server) handleDriverSummary(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	resp, err := s.openF1DriverSummary(year, driverNumber)
+	resp, err := openF1DriverSummary(client, year, driverNumber)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
 	if resp == nil {
 		http.Error(w, fmt.Sprintf("driver %d not found in %d championship", driverNumber, year), http.StatusNotFound)
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, resp)
 }
 
@@ -152,8 +163,8 @@ func (s *Server) localDriverSummary(year, driverNumber int) (driverSummaryRespon
 	return resp, sessionKey, true, nil
 }
 
-func (s *Server) openF1DriverSummary(year, driverNumber int) (*driverSummaryResponse, error) {
+func openF1DriverSummary(client *api.OpenF1Client, year, driverNumber int) (*driverSummaryResponse, error) {
-	champ, err := s.client.GetDriverChampionshipForYear(year)
+	champ, err := client.GetDriverChampionshipForYear(year)
 	if err != nil {
 		return nil, err
 	}
@@ -170,14 +181,14 @@ func (s *Server) openF1DriverSummary(year, driverNumber int) (*driverSummaryResp
 
 	driverInfo := map[int]models.Driver{}
 	sessionKey := champ[0].SessionKey
-	if ds, derr := s.client.GetDriversForSession(sessionKey); derr == nil {
+	if ds, derr := client.GetDriversForSession(sessionKey); derr == nil {
 		driverInfo = buildDriverMapFirst(ds)
 	}
-	if d, ok := s.championshipDriverInfo(entry.SessionKey, driverNumber, driverInfo); ok {
+	if d, ok := championshipDriverInfo(client, entry.SessionKey, driverNumber, driverInfo); ok {
 		driverInfo[driverNumber] = d
 	}
 
-	races, _, err := s.fetchSeasonRaces(year)
+	races, _, err := fetchSeasonRaces(client, year)
 	if err != nil {
 		return nil, err
 	}
@@ -194,8 +205,8 @@ func (s *Server) openF1DriverSummary(year, driverNumber int) (*driverSummaryResp
 // tryEnrichDriverSummary optionally fills headshot / polished identity from
 // OpenF1. It never blocks longer than driverEnrichmentTimeout — on timeout or
 // failure the local profile remains intact with enrichment=limited.
-func (s *Server) tryEnrichDriverSummary(resp *driverSummaryResponse, sessionKey int) {
+func tryEnrichDriverSummary(client *api.OpenF1Client, resp *driverSummaryResponse, sessionKey int) {
-	if resp == nil || s.client == nil || sessionKey <= 0 {
+	if resp == nil || client == nil || sessionKey <= 0 {
 		if resp != nil && resp.Enrichment == "none" {
 			// No session to enrich from — leave as none (local identity only).
 		}
@@ -209,7 +220,7 @@ func (s *Server) tryEnrichDriverSummary(resp *driverSummaryResponse, sessionKey
 
 	done := make(chan enrichResult, 1)
 	go func() {
-		d, ok := s.championshipDriverInfo(sessionKey, resp.DriverNumber, nil)
+		d, ok := championshipDriverInfo(client, sessionKey, resp.DriverNumber, nil)
 		done <- enrichResult{driver: d, ok: ok}
 	}()
 

internal/web/driversummary_test.go

@@ -250,6 +250,9 @@ func TestHandleDriverSummaryLocalFirstIgnoresHangingEnrichment(t *testing.T) {
 	if resp.Enrichment != "limited" {
 		t.Errorf("enrichment = %q, want limited", resp.Enrichment)
 	}
+	if rec.Header().Get(dataSourceHeader) != "local" || rec.Header().Get(dataFreshnessHeader) != "limited" {
+		t.Errorf("limited metadata = %q/%q", rec.Header().Get(dataSourceHeader), rec.Header().Get(dataFreshnessHeader))
+	}
 	if resp.DriverNumber != 1 || resp.NameAcronym != "VER" || resp.Points != 25 {
 		t.Errorf("local identity/results missing: %+v", resp)
 	}
@@ -289,6 +292,9 @@ func TestHandleDriverSummaryLocalFirstWithFailingEnrichment(t *testing.T) {
 	if resp.Enrichment != "limited" {
 		t.Errorf("enrichment = %q, want limited", resp.Enrichment)
 	}
+	if rec.Header().Get(dataSourceHeader) != "local" || rec.Header().Get(dataFreshnessHeader) != "limited" {
+		t.Errorf("limited metadata = %q/%q", rec.Header().Get(dataSourceHeader), rec.Header().Get(dataFreshnessHeader))
+	}
 	if resp.FullName != "Max Verstappen" {
 		t.Errorf("full_name = %q, want local identity", resp.FullName)
 	}
@@ -313,4 +319,7 @@ func TestHandleDriverSummarySourceLocalOnly(t *testing.T) {
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d body=%s", rec.Code, rec.Body.String())
 	}
+	if rec.Header().Get(dataSourceHeader) != "local" || rec.Header().Get(dataFreshnessHeader) != "local" {
+		t.Fatalf("local metadata = %q/%q", rec.Header().Get(dataSourceHeader), rec.Header().Get(dataFreshnessHeader))
+	}
 }

internal/web/freshness.go

@@ -0,0 +1,56 @@
+package web
+
+import (
+	"net/http"
+
+	"github.com/AmanTahiliani/box-box/internal/api"
+)
+
+const (
+	dataSourceHeader    = "X-BoxBox-Data-Source"
+	dataFreshnessHeader = "X-BoxBox-Data-Freshness"
+)
+
+// markOpenF1Response publishes request-scoped success provenance. Callers must
+// pass the scoped client used for this response, never Server.client.
+func markOpenF1Response(w http.ResponseWriter, client *api.OpenF1Client) {
+	markOpenF1AggregateResponse(w, client, false)
+}
+
+func markOpenF1AggregateResponse(w http.ResponseWriter, client *api.OpenF1Client, partial bool) {
+	w.Header().Set(dataSourceHeader, "openf1")
+	if client != nil && client.LastResponseWasStale() {
+		w.Header().Set(dataFreshnessHeader, "stale")
+		return
+	}
+	if partial {
+		w.Header().Set(dataFreshnessHeader, "partial")
+		return
+	}
+	w.Header().Set(dataFreshnessHeader, "fresh")
+}
+
+func markDataResponse(w http.ResponseWriter, source, freshness string) {
+	w.Header().Set(dataSourceHeader, source)
+	w.Header().Set(dataFreshnessHeader, freshness)
+}
+
+func markLocalResponse(w http.ResponseWriter, partial bool) {
+	w.Header().Set(dataSourceHeader, "local")
+	if partial {
+		w.Header().Set(dataFreshnessHeader, "partial")
+		return
+	}
+	w.Header().Set(dataFreshnessHeader, "local")
+}
+
+func markMixedResponse(w http.ResponseWriter, client *api.OpenF1Client, partial bool) {
+	w.Header().Set(dataSourceHeader, "mixed")
+	if client != nil && client.LastResponseWasStale() {
+		w.Header().Set(dataFreshnessHeader, "stale")
+	} else if partial {
+		w.Header().Set(dataFreshnessHeader, "partial")
+	} else {
+		w.Header().Set(dataFreshnessHeader, "local")
+	}
+}

internal/web/freshness_test.go

@@ -0,0 +1,72 @@
+package web
+
+import (
+	"database/sql"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/AmanTahiliani/box-box/internal/api"
+	_ "modernc.org/sqlite"
+)
+
+func TestOpenF1HandlerReportsFreshThenStaleSuccess(t *testing.T) {
+	year := time.Now().Year()
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, `[{"meeting_key":1,"meeting_name":"British Grand Prix","year":%d}]`, year)
+	}))
+	client := api.NewOpenF1Client(upstream.URL, time.Second)
+	t.Cleanup(func() { _ = client.Close() })
+	server := NewServer(client, 0, nil)
+	cacheKey := fmt.Sprintf("%s/v1/meetings?year=%d", upstream.URL, year)
+	requestURL := fmt.Sprintf("/api/v1/meetings?year=%d&source=openf1", year)
+	defer func() {
+		// Keep the shared application cache clean even if this test fails.
+		db, err := sql.Open("sqlite", api.DefaultCacheDBPath()+"?_busy_timeout=5000")
+		if err == nil {
+			_, _ = db.Exec(`DELETE FROM cache WHERE key = ?`, cacheKey)
+			_ = db.Close()
+		}
+	}()
+
+	fresh := httptest.NewRecorder()
+	server.handleMeetings(fresh, httptest.NewRequest(http.MethodGet, requestURL, nil))
+	if fresh.Code != http.StatusOK || fresh.Header().Get(dataSourceHeader) != "openf1" || fresh.Header().Get(dataFreshnessHeader) != "fresh" {
+		t.Fatalf("fresh response status/metadata = %d %q/%q body=%s", fresh.Code, fresh.Header().Get(dataSourceHeader), fresh.Header().Get(dataFreshnessHeader), fresh.Body.String())
+	}
+
+	db, err := sql.Open("sqlite", api.DefaultCacheDBPath()+"?_busy_timeout=5000")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := db.Exec(`UPDATE cache SET created_at = ? WHERE key = ?`, time.Now().Add(-48*time.Hour).Unix(), cacheKey); err != nil {
+		_ = db.Close()
+		t.Fatal(err)
+	}
+	_ = db.Close()
+	upstream.Close()
+
+	stale := httptest.NewRecorder()
+	server.handleMeetings(stale, httptest.NewRequest(http.MethodGet, requestURL, nil))
+	if stale.Code != http.StatusOK || stale.Header().Get(dataSourceHeader) != "openf1" || stale.Header().Get(dataFreshnessHeader) != "stale" {
+		t.Fatalf("stale response status/metadata = %d %q/%q body=%s", stale.Code, stale.Header().Get(dataSourceHeader), stale.Header().Get(dataFreshnessHeader), stale.Body.String())
+	}
+}
+
+func TestFreshnessHeadersAreExposedToBrowserClients(t *testing.T) {
+	handler := withCORS(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		markDataResponse(w, "local", "partial")
+		writeJSON(w, map[string]bool{"ok": true})
+	}))
+	recorder := httptest.NewRecorder()
+	handler.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/api/v1/test", nil))
+
+	if got := recorder.Header().Get("Access-Control-Expose-Headers"); got != dataSourceHeader+", "+dataFreshnessHeader {
+		t.Fatalf("exposed headers = %q", got)
+	}
+	if recorder.Header().Get(dataSourceHeader) != "local" || recorder.Header().Get(dataFreshnessHeader) != "partial" {
+		t.Fatalf("data metadata = %q/%q", recorder.Header().Get(dataSourceHeader), recorder.Header().Get(dataFreshnessHeader))
+	}
+}

internal/web/live.go

@@ -330,7 +330,15 @@ func cloneLivePositions(in map[string]live.LivePositionData) map[string]live.Liv
 
 // handleLiveState returns the current live data snapshot as JSON.
 func (s *Server) handleLiveState(w http.ResponseWriter, r *http.Request) {
-	writeJSON(w, s.hub.State())
+	state := s.hub.State()
+	freshness := "limited"
+	if state.IsLive {
+		freshness = "live"
+	} else if state.LastSnapshot != nil {
+		freshness = "archive"
+	}
+	markDataResponse(w, "fia", freshness)
+	writeJSON(w, state)
 }
 
 // handleSSEStream is the persistent SSE endpoint for live data.

internal/web/navigation.go

@@ -9,6 +9,7 @@ import (
 )
 
 func (s *Server) handleSeasons(w http.ResponseWriter, r *http.Request) {
+	markLocalResponse(w, false)
 	if !s.hasLocalQuery() {
 		writeJSON(w, []int{})
 		return
@@ -26,6 +27,7 @@ func (s *Server) handleSeasons(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) handleWeekend(w http.ResponseWriter, r *http.Request) {
+	markLocalResponse(w, false)
 	meetingKey, err := strconv.Atoi(r.URL.Query().Get("meeting_key"))
 	if err != nil || meetingKey == 0 {
 		http.Error(w, "meeting_key required", http.StatusBadRequest)
@@ -46,5 +48,6 @@ func (s *Server) handleWeekend(w http.ResponseWriter, r *http.Request) {
 		writeError(w, err, http.StatusInternalServerError, false)
 		return
 	}
+	markLocalResponse(w, weekend.Source == query.ResponseSourcePartial)
 	writeJSON(w, weekend)
 }

internal/web/racehub.go

@@ -17,6 +17,7 @@ func (s *Server) handleRaceHub(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if !s.hasLocalQuery() {
+		markDataResponse(w, "local", "limited")
 		writeJSON(w, emptyRaceHub(sessionKey))
 		return
 	}
@@ -26,6 +27,7 @@ func (s *Server) handleRaceHub(w http.ResponseWriter, r *http.Request) {
 		writeError(w, err, http.StatusInternalServerError, false)
 		return
 	}
+	markLocalResponse(w, hub.Source == query.ResponseSourcePartial)
 	writeJSON(w, hub)
 }
 

internal/web/racehub_test.go

@@ -86,6 +86,9 @@ func TestHandleRaceHubWithoutStore(t *testing.T) {
 	if hub.Source != query.ResponseSourceNone {
 		t.Fatalf("source = %q, want %q", hub.Source, query.ResponseSourceNone)
 	}
+	if rec.Header().Get(dataSourceHeader) != "local" || rec.Header().Get(dataFreshnessHeader) != "limited" {
+		t.Fatalf("missing hub metadata = %q/%q", rec.Header().Get(dataSourceHeader), rec.Header().Get(dataFreshnessHeader))
+	}
 	if hub.Datasets["session"].Status != query.DatasetStatusMissing {
 		t.Fatalf("session dataset = %+v, want missing", hub.Datasets["session"])
 	}
@@ -117,6 +120,12 @@ func TestHandleRaceHubWithLocalData(t *testing.T) {
 	if hub.Datasets["results"].Status != query.DatasetStatusMissing {
 		t.Fatalf("results dataset = %+v, want missing", hub.Datasets["results"])
 	}
+	if hub.Source != query.ResponseSourcePartial {
+		t.Fatalf("source = %q, want partial", hub.Source)
+	}
+	if rec.Header().Get(dataSourceHeader) != "local" || rec.Header().Get(dataFreshnessHeader) != "partial" {
+		t.Fatalf("partial hub metadata = %q/%q", rec.Header().Get(dataSourceHeader), rec.Header().Get(dataFreshnessHeader))
+	}
 }
 
 func TestHandleRaceHubIncludesChapters(t *testing.T) {

internal/web/replay.go

@@ -61,11 +61,13 @@ func (s *Server) handleReplayFrames(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	resp, err := assembleReplayFrames(r.Context(), s.client, sessionKey, intervalMS)
+	client := s.client.Scoped()
+	resp, err := assembleReplayFrames(r.Context(), client, sessionKey, intervalMS)
 	if err != nil {
-		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		writeError(w, err, http.StatusInternalServerError, client.LastResponseWasStale())
 		return
 	}
+	markOpenF1Response(w, client)
 	writeJSON(w, resp)
 }
 

internal/web/server.go

@@ -159,6 +159,7 @@ func withCORS(next http.Handler) http.Handler {
 		w.Header().Set("Access-Control-Allow-Origin", "*")
 		w.Header().Set("Access-Control-Allow-Methods", "GET, OPTIONS")
 		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+		w.Header().Set("Access-Control-Expose-Headers", dataSourceHeader+", "+dataFreshnessHeader)
 		if r.Method == http.MethodOptions {
 			w.WriteHeader(http.StatusNoContent)
 			return