diff --git a/backend/internal/handler/openai_gateway_credential_failover_test.go b/backend/internal/handler/openai_gateway_credential_failover_test.go
index 91a3881dfa..d94eae7fe9 100644
--- a/backend/internal/handler/openai_gateway_credential_failover_test.go
+++ b/backend/internal/handler/openai_gateway_credential_failover_test.go
@@ -326,12 +326,15 @@ func TestOpsRecoveredCredentialFailoverDoesNotCreateRequestError(t *testing.T) {
 	router.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/openai/v1/responses", nil))
 
 	require.Equal(t, http.StatusOK, recorder.Code)
-	require.Zero(t, OpsErrorLogQueueLength())
-	select {
-	case job := <-opsErrorLogQueue:
-		t.Fatalf("successful failover must not create ops error row: %+v", job.entry)
-	default:
-	}
+	require.Equal(t, int64(1), OpsErrorLogQueueLength())
+	job := <-opsErrorLogQueue
+	require.Equal(t, http.StatusOK, job.entry.StatusCode)
+	require.Equal(t, string(service.GatewayFailureStageAccountAuth), job.entry.ErrorPhase)
+	require.NotNil(t, job.entry.UpstreamErrorsJSON)
+	events, err := service.ParseOpsUpstreamErrors(*job.entry.UpstreamErrorsJSON)
+	require.NoError(t, err)
+	require.Len(t, events, 2)
+	require.Equal(t, string(service.GatewayFailureStageAccountAuth), events[1].Stage)
 }
 
 func TestOpsWebSocketCredentialFailoverSuccessDoesNotCreateRequestError(t *testing.T) {
@@ -354,12 +357,15 @@ func TestOpsWebSocketCredentialFailoverSuccessDoesNotCreateRequestError(t *testi
 	router.ServeHTTP(recorder, request)
 
 	require.Equal(t, http.StatusOK, recorder.Code)
-	require.Zero(t, OpsErrorLogQueueLength())
-	select {
-	case job := <-opsErrorLogQueue:
-		t.Fatalf("successful websocket failover must not create ops error row: %+v", job.entry)
-	default:
-	}
+	require.Equal(t, int64(1), OpsErrorLogQueueLength())
+	job := <-opsErrorLogQueue
+	require.Equal(t, http.StatusOK, job.entry.StatusCode)
+	require.Equal(t, string(service.GatewayFailureStageAccountAuth), job.entry.ErrorPhase)
+	require.NotNil(t, job.entry.UpstreamErrorsJSON)
+	events, err := service.ParseOpsUpstreamErrors(*job.entry.UpstreamErrorsJSON)
+	require.NoError(t, err)
+	require.Len(t, events, 1)
+	require.Equal(t, string(service.GatewayFailureStageAccountAuth), events[0].Stage)
 }
 
 func TestOpsWebSocketCredentialFailoverExhaustedIsRecorded(t *testing.T) {
diff --git a/backend/internal/handler/openai_gateway_handler.go b/backend/internal/handler/openai_gateway_handler.go
index 89e00c8954..45144479c7 100644
--- a/backend/internal/handler/openai_gateway_handler.go
+++ b/backend/internal/handler/openai_gateway_handler.go
@@ -409,7 +409,27 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 			h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "previous_response_id must be a response.id (resp_*), not a message id")
 			return
 		}
+		groupID := int64(0)
+		if apiKey.GroupID != nil {
+			groupID = *apiKey.GroupID
+		}
+		owned, ownershipErr := h.gatewayService.ValidateOpenAIHTTPResponseOwner(
+			c.Request.Context(),
+			groupID,
+			previousResponseID,
+			subject.UserID,
+			apiKey.ID,
+		)
+		if ownershipErr != nil {
+			reqLog.Warn("openai.previous_response_owner_lookup_failed", zap.Error(ownershipErr))
+		}
+		if !owned {
+			reqLog.Warn("openai.request_validation_failed", zap.String("reason", "previous_response_owner_mismatch"))
+			h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "previous_response_id is not available for this user")
+			return
+		}
 	}
+	service.SetOpenAIHTTPResponseOwner(c, subject.UserID, apiKey.ID)
 
 	setOpsRequestContext(c, reqModel, reqStream)
 	setOpsEndpointContext(c, "", int16(service.RequestTypeFromLegacy(reqStream, false)))
diff --git a/backend/internal/handler/openai_gateway_handler_test.go b/backend/internal/handler/openai_gateway_handler_test.go
index 6cc0eaffe7..86c56d4901 100644
--- a/backend/internal/handler/openai_gateway_handler_test.go
+++ b/backend/internal/handler/openai_gateway_handler_test.go
@@ -877,12 +877,61 @@ func TestOpenAIResponses_AcceptsHTTPContinuationPreviousResponseIDBeforeRouting(
 	})
 
 	h := newOpenAIHandlerForPreviousResponseIDValidation(t, nil)
+	require.NoError(t, h.gatewayService.BindOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_123456", 1, 101))
 	h.Responses(c)
 
 	require.NotEqual(t, http.StatusBadRequest, w.Code)
 	require.NotContains(t, w.Body.String(), "Responses WebSocket v2")
 }
 
+func TestOpenAIResponses_RejectsHTTPContinuationOwnedByAnotherUser(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest(http.MethodPost, "/openai/v1/responses", strings.NewReader(
+		`{"model":"gpt-5.1","stream":false,"previous_response_id":"resp_other_tenant","input":"hello"}`,
+	))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	groupID := int64(2)
+	c.Set(string(middleware.ContextKeyAPIKey), &service.APIKey{
+		ID:      202,
+		UserID:  2,
+		GroupID: &groupID,
+		User:    &service.User{ID: 2},
+	})
+	c.Set(string(middleware.ContextKeyUser), middleware.AuthSubject{UserID: 2, Concurrency: 1})
+
+	h := newOpenAIHandlerForPreviousResponseIDValidation(t, nil)
+	require.NoError(t, h.gatewayService.BindOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_other_tenant", 1, 101))
+	h.Responses(c)
+
+	require.Equal(t, http.StatusBadRequest, w.Code)
+	require.Contains(t, w.Body.String(), "previous_response_id is not available for this user")
+}
+
+func TestOpenAIResponses_RejectsUnownedHTTPContinuation(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest(http.MethodPost, "/openai/v1/responses", strings.NewReader(
+		`{"model":"gpt-5.1","stream":false,"previous_response_id":"resp_unknown","input":"hello"}`,
+	))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	groupID := int64(2)
+	c.Set(string(middleware.ContextKeyAPIKey), &service.APIKey{ID: 101, UserID: 1, GroupID: &groupID, User: &service.User{ID: 1}})
+	c.Set(string(middleware.ContextKeyUser), middleware.AuthSubject{UserID: 1, Concurrency: 1})
+
+	h := newOpenAIHandlerForPreviousResponseIDValidation(t, nil)
+	h.Responses(c)
+
+	require.Equal(t, http.StatusBadRequest, w.Code)
+	require.Contains(t, w.Body.String(), "previous_response_id is not available for this user")
+}
+
 func TestOpenAIResponses_FunctionCallOutputHTTPGuidanceDoesNotSuggestPreviousResponseReuse(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 
diff --git a/backend/internal/handler/ops_capture_writer_nil_test.go b/backend/internal/handler/ops_capture_writer_nil_test.go
index fce7680a16..38d3f1433b 100644
--- a/backend/internal/handler/ops_capture_writer_nil_test.go
+++ b/backend/internal/handler/ops_capture_writer_nil_test.go
@@ -12,6 +12,18 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+type blockingOpsResponseWriter struct {
+	gin.ResponseWriter
+	writeStarted chan struct{}
+	writeRelease chan struct{}
+}
+
+func (w *blockingOpsResponseWriter) WriteString(s string) (int, error) {
+	close(w.writeStarted)
+	<-w.writeRelease
+	return w.ResponseWriter.WriteString(s)
+}
+
 type deterministicOpsCaptureWriterStatePool struct {
 	states []*opsCaptureWriterState
 }
@@ -144,3 +156,56 @@ func TestOpsCaptureWriter_StaleLeaseCannotReachReacquiredState(t *testing.T) {
 	defer releaseOpsCaptureWriter(other)
 	require.NotSame(t, current.state, other.state)
 }
+
+func TestOpsCaptureWriter_ReleaseWaitsForDelegatedWriteWithoutHoldingStateMutex(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	pool := &deterministicOpsCaptureWriterStatePool{}
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	inner := &blockingOpsResponseWriter{
+		ResponseWriter: ctx.Writer,
+		writeStarted:   make(chan struct{}),
+		writeRelease:   make(chan struct{}),
+	}
+	w := acquireOpsCaptureWriterFromPool(pool, inner)
+
+	writeDone := make(chan struct{})
+	go func() {
+		defer close(writeDone)
+		_, _ = w.WriteString("body")
+	}()
+	<-inner.writeStarted
+
+	mutexAvailable := make(chan struct{})
+	go func() {
+		w.state.mu.Lock()
+		w.state.mu.Unlock()
+		close(mutexAvailable)
+	}()
+	select {
+	case <-mutexAvailable:
+	case <-time.After(time.Second):
+		t.Fatal("state mutex remained held across the delegated network write")
+	}
+
+	releaseDone := make(chan struct{})
+	go func() {
+		releaseOpsCaptureWriter(w)
+		close(releaseDone)
+	}()
+	select {
+	case <-releaseDone:
+		t.Fatal("release returned while a delegated write was still active")
+	case <-time.After(20 * time.Millisecond):
+	}
+	require.Empty(t, pool.states)
+
+	close(inner.writeRelease)
+	<-writeDone
+	select {
+	case <-releaseDone:
+	case <-time.After(time.Second):
+		t.Fatal("release did not finish after the delegated write returned")
+	}
+	require.Len(t, pool.states, 1)
+}
diff --git a/backend/internal/handler/ops_error_logger.go b/backend/internal/handler/ops_error_logger.go
index 5498f59706..41cd2119b9 100644
--- a/backend/internal/handler/ops_error_logger.go
+++ b/backend/internal/handler/ops_error_logger.go
@@ -528,6 +528,7 @@ type opsCaptureWriter struct {
 
 type opsCaptureWriterState struct {
 	mu             sync.RWMutex
+	inFlight       sync.WaitGroup
 	generation     uint64
 	responseWriter gin.ResponseWriter
 	limit          int
@@ -605,9 +606,15 @@ func releaseOpsCaptureWriter(w *opsCaptureWriter) {
 		state.mu.Unlock()
 		return
 	}
+	// Invalidate the lease before waiting. No new delegated calls can start for
+	// this handle, while calls that already copied the writer keep it alive via
+	// inFlight until their network operation returns.
 	state.generation++
 	state.responseWriter = nil
 	state.ctx = nil
+	state.mu.Unlock()
+	state.inFlight.Wait()
+	state.mu.Lock()
 	state.limit = opsCaptureWriterLimit
 	state.probe = state.probe[:0]
 	state.lineProbe = state.lineProbe[:0]
@@ -657,6 +664,27 @@ func (w *opsCaptureWriter) lockActiveWrite() (*opsCaptureWriterState, gin.Respon
 	return state, state.responseWriter
 }
 
+func (w *opsCaptureWriter) beginDelegatedCall() (*opsCaptureWriterState, gin.ResponseWriter) {
+	if w == nil || w.state == nil {
+		return nil, nil
+	}
+	state := w.state
+	state.mu.Lock()
+	if state.generation != w.generation || state.responseWriter == nil {
+		state.mu.Unlock()
+		return nil, nil
+	}
+	rw := state.responseWriter
+	state.inFlight.Add(1)
+	return state, rw
+}
+
+func finishDelegatedCall(state *opsCaptureWriterState) {
+	if state != nil {
+		state.inFlight.Done()
+	}
+}
+
 func (w *opsCaptureWriter) setContext(ctx *gin.Context) {
 	state, _ := w.lockActiveWrite()
 	if state == nil {
@@ -702,19 +730,21 @@ func (w *opsCaptureWriter) Header() http.Header {
 	return rw.Header()
 }
 func (w *opsCaptureWriter) WriteHeader(code int) {
-	state, rw := w.lockActive()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return
 	}
-	defer state.mu.RUnlock()
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	rw.WriteHeader(code)
 }
 func (w *opsCaptureWriter) WriteHeaderNow() {
-	state, rw := w.lockActive()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return
 	}
-	defer state.mu.RUnlock()
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	rw.WriteHeaderNow()
 }
 func (w *opsCaptureWriter) Status() int {
@@ -742,19 +772,21 @@ func (w *opsCaptureWriter) Written() bool {
 	return rw.Written()
 }
 func (w *opsCaptureWriter) Flush() {
-	state, rw := w.lockActive()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return
 	}
-	defer state.mu.RUnlock()
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	rw.Flush()
 }
 func (w *opsCaptureWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	state, rw := w.lockActive()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return nil, nil, errors.New("response writer released")
 	}
-	defer state.mu.RUnlock()
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	return rw.Hijack()
 }
 func (w *opsCaptureWriter) CloseNotify() <-chan bool {
@@ -777,26 +809,28 @@ func (w *opsCaptureWriter) Pusher() http.Pusher {
 }
 
 func (w *opsCaptureWriter) Write(b []byte) (int, error) {
-	state, rw := w.lockActiveWrite()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return 0, nil
 	}
-	defer state.mu.Unlock()
 	if state.shouldCapture() {
 		state.captureResponseChunk(b, rw.Status())
 	}
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	return rw.Write(b)
 }
 
 func (w *opsCaptureWriter) WriteString(s string) (int, error) {
-	state, rw := w.lockActiveWrite()
+	state, rw := w.beginDelegatedCall()
 	if state == nil {
 		return 0, nil
 	}
-	defer state.mu.Unlock()
 	if state.shouldCapture() {
 		state.captureResponseChunk([]byte(s), rw.Status())
 	}
+	state.mu.Unlock()
+	defer finishDelegatedCall(state)
 	return rw.WriteString(s)
 }
 
@@ -887,6 +921,13 @@ func (state *opsCaptureWriterState) captureResponseChunk(chunk []byte, status in
 		state.appendCapturedResponse(chunk)
 		return
 	}
+	// Most stream writes contain one or more complete successful SSE frames.
+	// Skip the byte-wise frame parser when the chunk cannot contain a terminal
+	// event and leaves no split frame to carry into the next write.
+	if len(state.probe) == 0 && len(state.lineProbe) == 0 && endsAtOpsSSEFrameBoundary(chunk) &&
+		!mayContainOpsTerminalSSE(chunk) {
+		return
+	}
 	for i, b := range chunk {
 		if state.skipLF {
 			state.skipLF = false
@@ -952,6 +993,20 @@ func (state *opsCaptureWriterState) captureResponseChunk(chunk []byte, status in
 	}
 }
 
+func endsAtOpsSSEFrameBoundary(chunk []byte) bool {
+	return bytes.HasSuffix(chunk, []byte("\n\n")) ||
+		bytes.HasSuffix(chunk, []byte("\r\n\r\n")) ||
+		bytes.HasSuffix(chunk, []byte("\r\r"))
+}
+
+func mayContainOpsTerminalSSE(chunk []byte) bool {
+	if bytes.Contains(chunk, []byte("response.failed")) {
+		return true
+	}
+	return bytes.Contains(chunk, []byte("error")) &&
+		(bytes.Contains(chunk, []byte("event")) || bytes.Contains(chunk, []byte(`"type"`)))
+}
+
 func isOpsTerminalSSEEventLine(line []byte) bool {
 	line = bytes.TrimSpace(line)
 	field, value, found := bytes.Cut(line, []byte{':'})
@@ -1066,10 +1121,14 @@ func OpsErrorLoggerMiddleware(ops *service.OpsService) gin.HandlerFunc {
 			if parsed.StreamFailure {
 				status = inferStreamFailureStatus(c, parsed)
 			} else {
-				// Locally generated in-band errors use an explicit context marker and
-				// may not have a capturable terminal frame. Preserve that fallback,
-				// but never turn recovered upstream attempts into request errors.
-				logOpsStreamError(c, ops, status)
+				// A marked in-band error is a visible request failure even though its
+				// wire status is already 200. Otherwise retain recovered attempts as a
+				// provider-health row whose 2xx status keeps it outside request SLA.
+				if len(service.GetOpsStreamErrors(c)) > 0 {
+					logOpsStreamError(c, ops, status)
+				} else {
+					logOpsRecoveredUpstream(c, ops, status)
+				}
 				return
 			}
 		}
@@ -1214,6 +1273,126 @@ func OpsErrorLoggerMiddleware(ops *service.OpsService) gin.HandlerFunc {
 	}
 }
 
+func logOpsRecoveredUpstream(c *gin.Context, ops *service.OpsService, finalStatus int) {
+	if c == nil || ops == nil || finalStatus >= 400 {
+		return
+	}
+
+	entry := &service.OpsInsertErrorLogInput{StatusCode: finalStatus}
+	applyOpsUpstreamFieldsFromContext(c, entry)
+	if entry.UpstreamStatusCode == nil && entry.UpstreamErrorMessage == nil &&
+		entry.UpstreamErrorDetail == nil && len(entry.UpstreamErrors) == 0 {
+		return
+	}
+
+	lastStatus := 0
+	if entry.UpstreamStatusCode != nil {
+		lastStatus = *entry.UpstreamStatusCode
+	}
+	lastStage := ""
+	for i := len(entry.UpstreamErrors) - 1; i >= 0; i-- {
+		if event := entry.UpstreamErrors[i]; event != nil {
+			lastStage = event.Stage
+			if event.AccountID > 0 {
+				accountID := event.AccountID
+				entry.AccountID = &accountID
+			}
+			break
+		}
+	}
+	if entry.AccountID == nil {
+		if accountID, ok := c.Get(opsAccountIDKey); ok {
+			if value, ok := accountID.(int64); ok && value > 0 {
+				entry.AccountID = &value
+			}
+		}
+	}
+
+	entry.ErrorPhase = "upstream"
+	entry.ErrorType = "upstream_error"
+	entry.ErrorSource = "upstream_http"
+	entry.ErrorOwner = "provider"
+	entry.Severity = classifyOpsSeverity(entry.ErrorType, lastStatus)
+	entry.IsCountTokens = isCountTokensRequest(c)
+	entry.CreatedAt = time.Now()
+	entry.ErrorMessage = "Recovered upstream error"
+	if lastStage == string(service.GatewayFailureStageAccountAuth) {
+		entry.ErrorPhase = string(service.GatewayFailureStageAccountAuth)
+		entry.ErrorMessage = "Recovered account authentication failure"
+	} else if lastStatus > 0 {
+		entry.ErrorMessage += " " + strconv.Itoa(lastStatus)
+	}
+	if entry.UpstreamErrorMessage != nil && strings.TrimSpace(*entry.UpstreamErrorMessage) != "" {
+		entry.ErrorMessage += ": " + strings.TrimSpace(*entry.UpstreamErrorMessage)
+	}
+	entry.ErrorMessage = truncateString(entry.ErrorMessage, 2048)
+
+	if c.Request != nil {
+		entry.UserAgent = c.GetHeader("User-Agent")
+		if c.Request.URL != nil {
+			entry.RequestPath = c.Request.URL.Path
+		}
+		if c.Request.Context() != nil {
+			entry.ClientRequestID, _ = c.Request.Context().Value(ctxkey.ClientRequestID).(string)
+			entry.RequestID, _ = c.Request.Context().Value(ctxkey.RequestID).(string)
+		}
+	}
+	entry.RequestID = strings.TrimSpace(entry.RequestID)
+	if entry.RequestID == "" {
+		entry.RequestID = c.Writer.Header().Get("X-Request-Id")
+	}
+	entry.Model = c.GetString(opsModelKey)
+	entry.RequestedModel = entry.Model
+	entry.Stream = c.GetBool(opsStreamKey)
+	entry.InboundEndpoint = GetInboundEndpoint(c)
+	entry.UpstreamModel = c.GetString(opsUpstreamModelKey)
+	entry.RequestType = opsRequestTypeFromContext(c)
+
+	apiKey := getOpsAPIKey(c)
+	fallbackPlatform := guessPlatformFromPath(entry.RequestPath)
+	var requestContext context.Context = context.Background()
+	if c.Request != nil {
+		requestContext = c.Request.Context()
+	}
+	entry.Platform = resolveOpsPlatform(requestContext, apiKey, fallbackPlatform)
+	entry.UpstreamEndpoint = GetUpstreamEndpoint(c, entry.Platform)
+	if apiKey != nil {
+		entry.APIKeyID = &apiKey.ID
+		entry.APIKeyPrefix = keyPrefix(apiKey.Key, 8)
+		if apiKey.User != nil {
+			entry.UserID = &apiKey.User.ID
+		}
+		if apiKey.GroupID != nil {
+			entry.GroupID = apiKey.GroupID
+		}
+		if apiKey.Group != nil && apiKey.Group.Platform != "" {
+			entry.Platform = apiKey.Group.Platform
+		}
+	}
+	if clientIP := strings.TrimSpace(ip.GetClientIP(c)); clientIP != "" {
+		entry.ClientIP = &clientIP
+	}
+	applyOpsLatencyFieldsFromContext(c, entry)
+	enqueueOpsErrorLog(ops, entry)
+}
+
+func opsRequestTypeFromContext(c *gin.Context) *int16 {
+	if c == nil {
+		return nil
+	}
+	if value, ok := c.Get(opsRequestTypeKey); ok {
+		switch typed := value.(type) {
+		case int16:
+			result := typed
+			return &result
+		case int:
+			result := int16(typed)
+			return &result
+		}
+	}
+	return nil
+}
+
 // logOpsStreamError 记录一次挂在已固化 HTTP 200 SSE 流上的就地错误。
 // 由于 wire 状态码停留在 200，常规的 status>=400 捕获路径永远不会触发；
 // handleStreamingAwareError 通过 service.MarkOpsStreamError 标记这类错误，
diff --git a/backend/internal/handler/ops_error_logger_test.go b/backend/internal/handler/ops_error_logger_test.go
index 1956ad2776..38176cb1b0 100644
--- a/backend/internal/handler/ops_error_logger_test.go
+++ b/backend/internal/handler/ops_error_logger_test.go
@@ -38,15 +38,18 @@ func (r *ingressRejectSettingRepo) Set(context.Context, string, string) error {
 type ingressRejectOpsRepo struct {
 	service.OpsRepository
 	insertCalls int
+	entries     []*service.OpsInsertErrorLogInput
 }
 
-func (r *ingressRejectOpsRepo) InsertErrorLog(context.Context, *service.OpsInsertErrorLogInput) (int64, error) {
+func (r *ingressRejectOpsRepo) InsertErrorLog(_ context.Context, entry *service.OpsInsertErrorLogInput) (int64, error) {
 	r.insertCalls++
+	r.entries = append(r.entries, entry)
 	return 0, nil
 }
 
-func (r *ingressRejectOpsRepo) BatchInsertErrorLogs(context.Context, []*service.OpsInsertErrorLogInput) (int64, error) {
+func (r *ingressRejectOpsRepo) BatchInsertErrorLogs(_ context.Context, entries []*service.OpsInsertErrorLogInput) (int64, error) {
 	r.insertCalls++
+	r.entries = append(r.entries, entries...)
 	return 0, nil
 }
 
@@ -328,11 +331,12 @@ func TestOpsErrorLoggerMiddleware_OrdinaryPermissionStillRecords(t *testing.T) {
 	require.Equal(t, http.StatusForbidden, job.entry.StatusCode)
 }
 
-func TestOpsErrorLoggerMiddleware_SkipsRecoveredUpstreamErrorOnSuccessfulRequest(t *testing.T) {
+func TestOpsErrorLoggerMiddleware_RecordsRecoveredUpstreamTelemetryOutsideFailureSLA(t *testing.T) {
 	setupOpsErrorLogTestQueue(t, 2)
 	gin.SetMode(gin.TestMode)
 
-	ops := service.NewOpsService(nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
+	repo := &ingressRejectOpsRepo{}
+	ops := service.NewOpsService(repo, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
 	router := gin.New()
 	router.Use(OpsErrorLoggerMiddleware(ops))
 	router.POST("/v1/responses", func(c *gin.Context) {
@@ -347,7 +351,50 @@ func TestOpsErrorLoggerMiddleware_SkipsRecoveredUpstreamErrorOnSuccessfulRequest
 	router.ServeHTTP(recorder, httptest.NewRequest(http.MethodPost, "/v1/responses", nil))
 
 	require.Equal(t, http.StatusOK, recorder.Code)
-	require.Zero(t, OpsErrorLogQueueLength())
+	require.Equal(t, int64(1), OpsErrorLogQueueLength())
+	job := <-opsErrorLogQueue
+	require.Nil(t, job.entry.UpstreamErrors, "raw attempts must be released before async queueing")
+	require.NotNil(t, job.entry.UpstreamErrorsJSON)
+	queuedEvents, err := service.ParseOpsUpstreamErrors(*job.entry.UpstreamErrorsJSON)
+	require.NoError(t, err)
+	require.Len(t, queuedEvents, 1)
+	require.Equal(t, http.StatusTooManyRequests, queuedEvents[0].UpstreamStatusCode)
+
+	flushOpsErrorLogBatch([]opsErrorLogJob{job})
+	require.Equal(t, 1, repo.insertCalls)
+	require.Len(t, repo.entries, 1)
+	persisted := repo.entries[0]
+	require.Equal(t, http.StatusOK, persisted.StatusCode, "recovered telemetry must remain outside failed-request SLA")
+	require.Equal(t, "upstream", persisted.ErrorPhase)
+	require.Equal(t, "upstream_error", persisted.ErrorType)
+	require.Equal(t, "Recovered upstream error 429: earlier attempt was rate limited", persisted.ErrorMessage)
+	require.NotNil(t, persisted.UpstreamErrorsJSON)
+	persistedEvents, err := service.ParseOpsUpstreamErrors(*persisted.UpstreamErrorsJSON)
+	require.NoError(t, err)
+	require.Len(t, persistedEvents, 1)
+	require.Equal(t, http.StatusTooManyRequests, persistedEvents[0].UpstreamStatusCode)
+}
+
+func TestOpsErrorLoggerMiddleware_IntermediateSkipMonitoringDoesNotHideFinalVisibleFailure(t *testing.T) {
+	setupOpsErrorLogTestQueue(t, 2)
+	gin.SetMode(gin.TestMode)
+	ops := service.NewOpsService(nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
+	router := gin.New()
+	router.Use(OpsErrorLoggerMiddleware(ops))
+	router.POST("/v1/responses", func(c *gin.Context) {
+		c.Set(service.OpsUpstreamErrorsKey, []*service.OpsUpstreamErrorEvent{
+			{UpstreamStatusCode: http.StatusBadGateway, Message: "hidden retry", SkipMonitoring: true},
+			{UpstreamStatusCode: http.StatusServiceUnavailable, Message: "visible final"},
+		})
+		c.JSON(http.StatusServiceUnavailable, gin.H{"error": gin.H{"type": "upstream_error", "message": "visible final"}})
+	})
+
+	recorder := httptest.NewRecorder()
+	router.ServeHTTP(recorder, httptest.NewRequest(http.MethodPost, "/v1/responses", nil))
+	require.Equal(t, int64(1), OpsErrorLogQueueLength())
+	job := <-opsErrorLogQueue
+	require.Equal(t, http.StatusServiceUnavailable, job.entry.StatusCode)
+	require.Equal(t, "visible final", job.entry.ErrorMessage)
 }
 
 func TestOpsErrorLoggerMiddleware_CapturesSplitResponsesFailedSSE(t *testing.T) {
diff --git a/backend/internal/repository/gateway_cache.go b/backend/internal/repository/gateway_cache.go
index f67e92b263..36935160da 100644
--- a/backend/internal/repository/gateway_cache.go
+++ b/backend/internal/repository/gateway_cache.go
@@ -270,27 +270,47 @@ func (c *gatewayCache) GetReasoningContent(ctx context.Context, itemID string) (
 }
 
 const (
-	cyberSessionBlockPrefix = "cyber_session_block:"
-	cyberSessionScopePrefix = "cyber_session_scope:"
+	cyberSessionBlockPrefix         = "cyber_session_block:"
+	cyberSessionScopePrefix         = "cyber_session_scope:"
+	cyberSessionRedisCommandMaxKeys = 128
 )
 
-// SetCyberSessionBlocked atomically writes all exact blocks and their optional
-// coarse source scope with the same TTL.
+// SetCyberSessionBlocked writes exact blocks in bounded transactions. The
+// coarse scope is activated only after all exact blocks have been stored.
 func (c *gatewayCache) SetCyberSessionBlocked(ctx context.Context, scopeKey string, keys []string, ttl time.Duration) error {
 	if len(keys) == 0 {
 		return nil
 	}
-	pipe := c.rdb.TxPipeline()
-	for _, key := range keys {
-		if key != "" {
+	exactKeys := make([]string, 0, cyberSessionRedisCommandMaxKeys)
+	flush := func() error {
+		if len(exactKeys) == 0 {
+			return nil
+		}
+		pipe := c.rdb.TxPipeline()
+		for _, key := range exactKeys {
 			pipe.Set(ctx, cyberSessionBlockPrefix+key, "1", ttl)
 		}
+		_, err := pipe.Exec(ctx)
+		exactKeys = exactKeys[:0]
+		return err
+	}
+	for _, key := range keys {
+		if key != "" {
+			exactKeys = append(exactKeys, key)
+			if len(exactKeys) == cyberSessionRedisCommandMaxKeys {
+				if err := flush(); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	if err := flush(); err != nil {
+		return err
 	}
 	if scopeKey != "" {
-		pipe.Set(ctx, cyberSessionScopePrefix+scopeKey, "1", ttl)
+		return c.rdb.Set(ctx, cyberSessionScopePrefix+scopeKey, "1", ttl).Err()
 	}
-	_, err := pipe.Exec(ctx)
-	return err
+	return nil
 }
 
 func (c *gatewayCache) IsCyberSessionScopeActive(ctx context.Context, scopeKey string) (bool, error) {
@@ -301,23 +321,29 @@ func (c *gatewayCache) IsCyberSessionScopeActive(ctx context.Context, scopeKey s
 	return n > 0, nil
 }
 
-// FindCyberSessionBlocked checks transcript-prefix candidates in one Redis
-// round trip and returns the first blocked key in caller order.
+// FindCyberSessionBlocked checks bounded batches in caller order and stops at
+// the first blocked key, preserving the original earliest-match behavior.
 func (c *gatewayCache) FindCyberSessionBlocked(ctx context.Context, keys []string) (string, error) {
 	if len(keys) == 0 {
 		return "", nil
 	}
-	redisKeys := make([]string, len(keys))
-	for i, key := range keys {
-		redisKeys[i] = cyberSessionBlockPrefix + key
-	}
-	values, err := c.rdb.MGet(ctx, redisKeys...).Result()
-	if err != nil {
-		return "", err
-	}
-	for i, value := range values {
-		if value != nil {
-			return keys[i], nil
+	for start := 0; start < len(keys); start += cyberSessionRedisCommandMaxKeys {
+		end := start + cyberSessionRedisCommandMaxKeys
+		if end > len(keys) {
+			end = len(keys)
+		}
+		redisKeys := make([]string, end-start)
+		for i, key := range keys[start:end] {
+			redisKeys[i] = cyberSessionBlockPrefix + key
+		}
+		values, err := c.rdb.MGet(ctx, redisKeys...).Result()
+		if err != nil {
+			return "", err
+		}
+		for i, value := range values {
+			if value != nil {
+				return keys[start+i], nil
+			}
 		}
 	}
 	return "", nil
diff --git a/backend/internal/repository/gateway_cache_cyber_test.go b/backend/internal/repository/gateway_cache_cyber_test.go
index 40396e7c26..03f29e82a1 100644
--- a/backend/internal/repository/gateway_cache_cyber_test.go
+++ b/backend/internal/repository/gateway_cache_cyber_test.go
@@ -2,6 +2,8 @@ package repository
 
 import (
 	"context"
+	"strconv"
+	"sync"
 	"testing"
 	"time"
 
@@ -11,6 +13,42 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+type cyberRedisCommandHook struct {
+	mu            sync.Mutex
+	mgetKeyCounts []int
+	setBatchSizes []int
+}
+
+func (h *cyberRedisCommandHook) DialHook(next redis.DialHook) redis.DialHook { return next }
+
+func (h *cyberRedisCommandHook) ProcessHook(next redis.ProcessHook) redis.ProcessHook {
+	return func(ctx context.Context, cmd redis.Cmder) error {
+		if cmd.Name() == "mget" {
+			h.mu.Lock()
+			h.mgetKeyCounts = append(h.mgetKeyCounts, len(cmd.Args())-1)
+			h.mu.Unlock()
+		}
+		return next(ctx, cmd)
+	}
+}
+
+func (h *cyberRedisCommandHook) ProcessPipelineHook(next redis.ProcessPipelineHook) redis.ProcessPipelineHook {
+	return func(ctx context.Context, cmds []redis.Cmder) error {
+		setCount := 0
+		for _, cmd := range cmds {
+			if cmd.Name() == "set" {
+				setCount++
+			}
+		}
+		if setCount > 0 {
+			h.mu.Lock()
+			h.setBatchSizes = append(h.setBatchSizes, setCount)
+			h.mu.Unlock()
+		}
+		return next(ctx, cmds)
+	}
+}
+
 func TestGatewayCacheCyberBlockWritesScopeAndExactKeysTogether(t *testing.T) {
 	server := miniredis.RunT(t)
 	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
@@ -29,3 +67,31 @@ func TestGatewayCacheCyberBlockWritesScopeAndExactKeysTogether(t *testing.T) {
 	require.Greater(t, server.TTL(cyberSessionScopePrefix+"scope-1"), time.Duration(0))
 	require.Equal(t, server.TTL(cyberSessionBlockPrefix+"block-1"), server.TTL(cyberSessionBlockPrefix+"block-2"))
 }
+
+func TestGatewayCacheCyberBlockCommandsAreBoundedAndLookupShortCircuits(t *testing.T) {
+	server := miniredis.RunT(t)
+	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
+	t.Cleanup(func() { _ = client.Close() })
+	hook := &cyberRedisCommandHook{}
+	client.AddHook(hook)
+	store, ok := NewGatewayCache(client).(service.CyberSessionBlockStore)
+	require.True(t, ok)
+
+	keys := make([]string, cyberSessionRedisCommandMaxKeys*2+44)
+	for i := range keys {
+		keys[i] = "block-" + strconv.Itoa(i)
+	}
+	ctx := context.Background()
+	require.NoError(t, store.SetCyberSessionBlocked(ctx, "large-scope", keys, time.Minute))
+	require.Equal(t, []int{cyberSessionRedisCommandMaxKeys, cyberSessionRedisCommandMaxKeys, 44}, hook.setBatchSizes)
+
+	lookup := make([]string, len(keys))
+	for i := range lookup {
+		lookup[i] = "missing-" + strconv.Itoa(i)
+	}
+	lookup[cyberSessionRedisCommandMaxKeys+3] = keys[cyberSessionRedisCommandMaxKeys+3]
+	matched, err := store.FindCyberSessionBlocked(ctx, lookup)
+	require.NoError(t, err)
+	require.Equal(t, keys[cyberSessionRedisCommandMaxKeys+3], matched)
+	require.Equal(t, []int{cyberSessionRedisCommandMaxKeys, cyberSessionRedisCommandMaxKeys}, hook.mgetKeyCounts)
+}
diff --git a/backend/internal/repository/temp_unsched_cache.go b/backend/internal/repository/temp_unsched_cache.go
index c145a30476..42c2fd648c 100644
--- a/backend/internal/repository/temp_unsched_cache.go
+++ b/backend/internal/repository/temp_unsched_cache.go
@@ -141,8 +141,3 @@ func (c *tempUnschedCache) RecordOpenAIAPIKeyHealthFailure(ctx context.Context,
 	}
 	return count, tripped == 1, nil
 }
-
-func (c *tempUnschedCache) ResetOpenAIAPIKeyHealthFailures(ctx context.Context, accountID int64) error {
-	key := c.openAIAPIKeyHealthKey(accountID)
-	return c.rdb.Del(ctx, key, key+":sequence").Err()
-}
diff --git a/backend/internal/repository/temp_unsched_cache_health_test.go b/backend/internal/repository/temp_unsched_cache_health_test.go
index 092b85ac6b..1b8a1f10c6 100644
--- a/backend/internal/repository/temp_unsched_cache_health_test.go
+++ b/backend/internal/repository/temp_unsched_cache_health_test.go
@@ -3,6 +3,7 @@ package repository
 import (
 	"context"
 	"testing"
+	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/service"
 	"github.com/alicebob/miniredis/v2"
@@ -10,7 +11,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestOpenAIAPIKeyHealthCacheTripsAndSuccessResetsWindow(t *testing.T) {
+func TestOpenAIAPIKeyHealthCacheTripsWithinRollingWindow(t *testing.T) {
 	server := miniredis.RunT(t)
 	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
 	t.Cleanup(func() { _ = client.Close() })
@@ -18,14 +19,6 @@ func TestOpenAIAPIKeyHealthCacheTripsAndSuccessResetsWindow(t *testing.T) {
 	require.True(t, ok)
 
 	ctx := context.Background()
-	for attempt := 1; attempt <= 2; attempt++ {
-		count, tripped, err := store.RecordOpenAIAPIKeyHealthFailure(ctx, 42, 1, 3)
-		require.NoError(t, err)
-		require.EqualValues(t, attempt, count)
-		require.False(t, tripped)
-	}
-	require.NoError(t, store.ResetOpenAIAPIKeyHealthFailures(ctx, 42))
-
 	for attempt := 1; attempt <= 3; attempt++ {
 		count, tripped, err := store.RecordOpenAIAPIKeyHealthFailure(ctx, 42, 1, 3)
 		require.NoError(t, err)
@@ -33,3 +26,25 @@ func TestOpenAIAPIKeyHealthCacheTripsAndSuccessResetsWindow(t *testing.T) {
 		require.Equal(t, attempt == 3, tripped)
 	}
 }
+
+func TestOpenAIAPIKeyHealthCacheDropsFailuresOutsideRollingWindow(t *testing.T) {
+	server := miniredis.RunT(t)
+	now := time.Unix(1_700_000_000, 0)
+	server.SetTime(now)
+	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
+	t.Cleanup(func() { _ = client.Close() })
+	store, ok := NewTempUnschedCache(client).(service.OpenAIAPIKeyHealthCache)
+	require.True(t, ok)
+
+	ctx := context.Background()
+	count, tripped, err := store.RecordOpenAIAPIKeyHealthFailure(ctx, 42, 1, 3)
+	require.NoError(t, err)
+	require.EqualValues(t, 1, count)
+	require.False(t, tripped)
+
+	server.SetTime(now.Add(61 * time.Second))
+	count, tripped, err = store.RecordOpenAIAPIKeyHealthFailure(ctx, 42, 1, 3)
+	require.NoError(t, err)
+	require.EqualValues(t, 1, count)
+	require.False(t, tripped)
+}
diff --git a/backend/internal/service/openai_access_state_failover_test.go b/backend/internal/service/openai_access_state_failover_test.go
index 0acaa26182..a46f9ca571 100644
--- a/backend/internal/service/openai_access_state_failover_test.go
+++ b/backend/internal/service/openai_access_state_failover_test.go
@@ -24,22 +24,59 @@ func (r *openAIStream403AccountRepo) SetError(context.Context, int64, string) er
 	return nil
 }
 
+type openAIAuthPolicyAccountRepo struct {
+	AccountRepository
+	tempCalls     int
+	setErrorCalls int
+}
+
+func (r *openAIAuthPolicyAccountRepo) SetTempUnschedulable(context.Context, int64, time.Time, string) error {
+	r.tempCalls++
+	return nil
+}
+
+func (r *openAIAuthPolicyAccountRepo) SetError(context.Context, int64, string) error {
+	r.setErrorCalls++
+	return nil
+}
+
+type openAIAuthPolicy403Counter struct {
+	counts []int64
+}
+
+func (s *openAIAuthPolicy403Counter) IncrementOpenAI403Count(context.Context, int64, int) (int64, error) {
+	if len(s.counts) == 0 {
+		return 1, nil
+	}
+	count := s.counts[0]
+	s.counts = s.counts[1:]
+	return count, nil
+}
+
+func (*openAIAuthPolicy403Counter) ResetOpenAI403Count(context.Context, int64) error {
+	return nil
+}
+
 func TestOpenAIUpstreamAccessStateClassification(t *testing.T) {
 	tests := []struct {
 		name string
 		body string
+		want bool
 	}{
-		{"workspace_code", `{"detail":{"code":"deactivated_workspace"}}`},
-		{"disabled_account", `{"error":{"message":"Your account is disabled"}}`},
-		{"suspended_workspace", `{"response":{"error":{"message":"This workspace has been suspended"}}}`},
-		{"deactivated_organization", `{"detail":{"message":"The organization is deactivated"}}`},
-		{"scalar_detail", `{"detail":"This workspace has been disabled"}`},
-		{"suspended_org_code", `{"error":{"code":"org_suspended"}}`},
+		{"workspace_code", `{"detail":{"code":"deactivated_workspace"}}`, true},
+		{"disabled_account_message", `{"error":{"message":"Your account is disabled"}}`, false},
+		{"suspended_workspace_message", `{"response":{"error":{"message":"This workspace has been suspended"}}}`, false},
+		{"deactivated_organization_message", `{"detail":{"message":"The organization is deactivated"}}`, false},
+		{"scalar_detail", `{"detail":"This workspace has been disabled"}`, false},
+		{"suspended_org_code", `{"error":{"code":"org_suspended"}}`, true},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			body := []byte(tt.body)
-			require.True(t, isOpenAIUpstreamAccessStateError("", body))
+			require.Equal(t, tt.want, isOpenAIUpstreamAccessStateError("", body))
+			if !tt.want {
+				return
+			}
 			require.True(t, (&OpenAIGatewayService{}).shouldFailoverOpenAIUpstreamResponse(http.StatusForbidden, "", body))
 			require.True(t, shouldFailoverOpenAIPassthroughResponse(&Account{Type: AccountTypeOAuth}, http.StatusForbidden, body))
 
@@ -62,6 +99,93 @@ func TestOpenAIUpstreamAccessStateDoesNotScanEchoedJSON(t *testing.T) {
 	require.False(t, shouldFailoverOpenAIPassthroughResponse(&Account{Type: AccountTypeOAuth}, http.StatusBadRequest, body))
 }
 
+func TestOpenAIHTTPAccessStateDoesNotTrustBadRequestMessage(t *testing.T) {
+	body := []byte(`{"error":{"type":"invalid_request_error","code":"unknown_parameter","message":"Unknown parameter: account disabled"}}`)
+	svc := &OpenAIGatewayService{}
+
+	require.False(t, isOpenAIUpstreamAccessStateError("", body), "free-form stream messages are not durable account evidence")
+	require.False(t, isOpenAIHTTPUpstreamAccessStateError(http.StatusBadRequest, "", body))
+	require.False(t, svc.shouldFailoverOpenAIUpstreamResponse(http.StatusBadRequest, "", body))
+	require.False(t, shouldFailoverOpenAIPassthroughResponse(&Account{Type: AccountTypeOAuth}, http.StatusBadRequest, body))
+
+	err := newOpenAIUpstreamFailoverError(http.StatusBadRequest, nil, body, "", false)
+	require.False(t, err.IsCredentialFailure())
+}
+
+func TestOpenAIHTTPAccessStateBadRequestDoesNotDisableAccount(t *testing.T) {
+	repo := &openAIStream403AccountRepo{}
+	svc := &OpenAIGatewayService{rateLimitService: &RateLimitService{accountRepo: repo}}
+	account := &Account{ID: 925, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Status: StatusActive, Schedulable: true}
+	body := []byte(`{"error":{"code":"unknown_parameter","message":"Unknown parameter: account disabled"}}`)
+
+	disabled := svc.handleOpenAIAccountUpstreamError(context.Background(), account, http.StatusBadRequest, nil, body)
+
+	require.False(t, disabled)
+	require.Zero(t, repo.setErrorCalls)
+	require.False(t, svc.isOpenAIAccountRuntimeBlocked(account))
+}
+
+func TestOpenAIStreamEchoedAccessStateMessageDoesNotDisableOrFailover(t *testing.T) {
+	repo := &openAIStream403AccountRepo{}
+	svc := &OpenAIGatewayService{rateLimitService: &RateLimitService{accountRepo: repo}}
+	account := &Account{ID: 926, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Status: StatusActive, Schedulable: true}
+	payload := []byte(`{"type":"response.failed","response":{"error":{"type":"invalid_request_error","code":"unknown_parameter","message":"Unknown parameter: account disabled"}}}`)
+	message := extractOpenAISSEErrorMessage(payload)
+
+	require.False(t, isOpenAIUpstreamAccessStateError(message, payload))
+	require.False(t, openAIStreamFailedEventShouldFailover(payload, message))
+	status, disabled := svc.handleOpenAIStreamTerminalAccountSideEffects(nil, account, payload, message, nil)
+	require.Equal(t, http.StatusBadGateway, status)
+	require.False(t, disabled)
+	require.Zero(t, repo.setErrorCalls)
+	require.False(t, svc.isOpenAIAccountRuntimeBlocked(account))
+}
+
+func TestOpenAIHTTPAccessStateTrustsStructuredCode(t *testing.T) {
+	repo := &openAIStream403AccountRepo{}
+	svc := &OpenAIGatewayService{rateLimitService: &RateLimitService{accountRepo: repo}}
+	account := &Account{ID: 930, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Status: StatusActive, Schedulable: true}
+	body := []byte(`{"error":{"code":"organization_deactivated","message":"request rejected"}}`)
+
+	require.True(t, isOpenAIHTTPUpstreamAccessStateError(http.StatusBadRequest, "", body))
+	require.True(t, svc.shouldFailoverOpenAIUpstreamResponse(http.StatusBadRequest, "", body))
+	require.True(t, svc.handleOpenAIAccountUpstreamError(context.Background(), account, http.StatusBadRequest, nil, body))
+	require.Equal(t, 1, repo.setErrorCalls)
+	require.True(t, svc.isOpenAIAccountRuntimeBlocked(account))
+}
+
+func TestOpenAIHTTPAuthMessagesUseExistingStatusPolicies(t *testing.T) {
+	t.Run("oauth 401 remains recoverable", func(t *testing.T) {
+		repo := &openAIAuthPolicyAccountRepo{}
+		rateLimits := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+		svc := &OpenAIGatewayService{rateLimitService: rateLimits}
+		account := &Account{ID: 931, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Status: StatusActive, Schedulable: true,
+			Credentials: map[string]any{"refresh_token": "refreshable"}}
+		body := []byte(`{"error":{"message":"account is disabled"}}`)
+
+		require.False(t, isOpenAIHTTPUpstreamAccessStateError(http.StatusUnauthorized, "", body))
+		require.True(t, svc.handleOpenAIAccountUpstreamError(context.Background(), account, http.StatusUnauthorized, nil, body))
+		require.Zero(t, repo.setErrorCalls)
+		require.Equal(t, 1, repo.tempCalls)
+	})
+
+	t.Run("403 uses counter cooldown", func(t *testing.T) {
+		repo := &openAIAuthPolicyAccountRepo{}
+		counter := &openAIAuthPolicy403Counter{counts: []int64{1}}
+		rateLimits := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+		rateLimits.openAI403CounterCache = counter
+		svc := &OpenAIGatewayService{rateLimitService: rateLimits}
+		rateLimits.SetAccountRuntimeBlocker(svc)
+		account := &Account{ID: 932, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Status: StatusActive, Schedulable: true}
+		body := []byte(`{"error":{"message":"workspace has been suspended"}}`)
+
+		require.False(t, isOpenAIHTTPUpstreamAccessStateError(http.StatusForbidden, "", body))
+		require.True(t, svc.handleOpenAIAccountUpstreamError(context.Background(), account, http.StatusForbidden, nil, body))
+		require.Zero(t, repo.setErrorCalls)
+		require.Equal(t, 1, repo.tempCalls)
+	})
+}
+
 func TestOpenAICyberPolicyWrapped5xxNeverFailsOver(t *testing.T) {
 	body := []byte(`{"error":{"code":"cyber_policy","message":"blocked"}}`)
 	svc := &OpenAIGatewayService{}
diff --git a/backend/internal/service/openai_account_runtime_block_fastpath.go b/backend/internal/service/openai_account_runtime_block_fastpath.go
index a25d78c697..1d8da95913 100644
--- a/backend/internal/service/openai_account_runtime_block_fastpath.go
+++ b/backend/internal/service/openai_account_runtime_block_fastpath.go
@@ -65,7 +65,7 @@ func (s *OpenAIGatewayService) handleOpenAIAccountUpstreamError(ctx context.Cont
 	}
 	stateCtx, cancel := openAIAccountStateContext(ctx)
 	defer cancel()
-	if account != nil && account.Platform == PlatformOpenAI && isOpenAIUpstreamAccessStateError("", responseBody) {
+	if account != nil && account.Platform == PlatformOpenAI && isOpenAIHTTPUpstreamAccessStateError(statusCode, "", responseBody) {
 		message := "OpenAI upstream account or workspace is unavailable"
 		if upstreamMsg := strings.TrimSpace(extractUpstreamErrorMessage(responseBody)); upstreamMsg != "" {
 			message = upstreamMsg
diff --git a/backend/internal/service/openai_account_runtime_block_fastpath_test.go b/backend/internal/service/openai_account_runtime_block_fastpath_test.go
index 97bfae0eee..db620cc5b8 100644
--- a/backend/internal/service/openai_account_runtime_block_fastpath_test.go
+++ b/backend/internal/service/openai_account_runtime_block_fastpath_test.go
@@ -15,11 +15,13 @@ import (
 
 type oauth429RateLimitRepo struct {
 	AccountRepository
-	setRateLimitedCalls int
+	setRateLimitedCalls  int
+	lastRateLimitedUntil time.Time
 }
 
-func (r *oauth429RateLimitRepo) SetRateLimited(context.Context, int64, time.Time) error {
+func (r *oauth429RateLimitRepo) SetRateLimited(_ context.Context, _ int64, until time.Time) error {
 	r.setRateLimitedCalls++
+	r.lastRateLimitedUntil = until
 	return nil
 }
 
@@ -60,6 +62,52 @@ func TestOpenAI429FastPath_BlocksOAuthOnlyAfterRetryWindow(t *testing.T) {
 	require.False(t, svc.shouldRetryOpenAIOAuth429OnSameAccount(account, http.StatusTooManyRequests, false))
 }
 
+func TestOpenAIStream429IgnoresSuccessfulQuotaSnapshotHeaders(t *testing.T) {
+	repo := &oauth429RateLimitRepo{}
+	rateLimits := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+	svc := &OpenAIGatewayService{rateLimitService: rateLimits}
+	rateLimits.SetAccountRuntimeBlocker(svc)
+	account := &Account{ID: 421, Platform: PlatformOpenAI, Type: AccountTypeOAuth}
+	svc.openaiOAuth429RetryStartedAt.Store(account.ID, time.Now().Add(-openAIOAuth429RetryWindow-time.Second))
+	headers := http.Header{}
+	headers.Set("x-codex-primary-used-percent", "37")
+	headers.Set("x-codex-primary-reset-after-seconds", "604800")
+	headers.Set("x-codex-primary-window-minutes", "10080")
+	payload := []byte(`{"type":"error","error":{"type":"rate_limit_error","code":"rate_limit_exceeded","message":"slow down"}}`)
+
+	status, disabled := svc.handleOpenAIStreamTerminalAccountSideEffects(nil, account, payload, "slow down", headers)
+
+	require.Equal(t, http.StatusTooManyRequests, status)
+	require.False(t, disabled)
+	require.True(t, svc.isOpenAIAccountRuntimeBlocked(account))
+	value, ok := svc.openaiAccountRuntimeBlockUntil.Load(account.ID)
+	require.True(t, ok)
+	blockedUntil, ok := value.(time.Time)
+	require.True(t, ok)
+	require.Less(t, time.Until(blockedUntil), time.Minute, "stream 429 must not inherit the normal seven-day quota snapshot")
+	if !repo.lastRateLimitedUntil.IsZero() {
+		require.Less(t, time.Until(repo.lastRateLimitedUntil), time.Minute)
+	}
+}
+
+func TestOpenAIHTTP429StillUsesQuotaResetHeaders(t *testing.T) {
+	svc := &OpenAIGatewayService{rateLimitService: &RateLimitService{}}
+	account := &Account{ID: 422, Platform: PlatformOpenAI, Type: AccountTypeOAuth}
+	svc.openaiOAuth429RetryStartedAt.Store(account.ID, time.Now().Add(-openAIOAuth429RetryWindow-time.Second))
+	headers := http.Header{}
+	headers.Set("x-codex-primary-used-percent", "37")
+	headers.Set("x-codex-primary-reset-after-seconds", "604800")
+	headers.Set("x-codex-primary-window-minutes", "10080")
+
+	svc.markOpenAIOAuth429RateLimited(context.Background(), account, headers, nil)
+
+	value, ok := svc.openaiAccountRuntimeBlockUntil.Load(account.ID)
+	require.True(t, ok)
+	blockedUntil, ok := value.(time.Time)
+	require.True(t, ok)
+	require.Greater(t, time.Until(blockedUntil), 6*24*time.Hour, "real HTTP 429 must retain the upstream quota reset")
+}
+
 func TestOpenAI429RetryDelayHonorsBoundedRetryAfter(t *testing.T) {
 	deadline := time.Now().Add(openAIOAuth429RetryWindow)
 	require.Equal(t, openAIOAuth429RetryDelay, openAIOAuth429SameAccountRetryDelay(nil, deadline))
diff --git a/backend/internal/service/openai_alpha_search.go b/backend/internal/service/openai_alpha_search.go
index 1954dc2670..c22545f5f1 100644
--- a/backend/internal/service/openai_alpha_search.go
+++ b/backend/internal/service/openai_alpha_search.go
@@ -104,7 +104,7 @@ func (s *OpenAIGatewayService) ForwardAlphaSearch(ctx context.Context, c *gin.Co
 			if account.IsOpenAIOAuthLike() && resp.StatusCode == http.StatusTooManyRequests {
 				return nil, s.newOpenAIAccountFailoverError(account, resp.StatusCode, resp.Header, respBody, upstreamMessage, shouldDisable, retryableOnSameAccount)
 			}
-			if isOpenAIUpstreamAccessStateError(upstreamMessage, respBody) {
+			if isOpenAIHTTPUpstreamAccessStateError(resp.StatusCode, upstreamMessage, respBody) {
 				return nil, newOpenAIUpstreamFailoverError(resp.StatusCode, resp.Header, respBody, upstreamMessage, retryableOnSameAccount)
 			}
 			return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode, ResponseBody: respBody, RetryableOnSameAccount: retryableOnSameAccount}
@@ -182,7 +182,7 @@ func (s *OpenAIGatewayService) forwardAlphaSearchViaResponsesWebSearch(
 			if account.IsOpenAIOAuthLike() && resp.StatusCode == http.StatusTooManyRequests {
 				return nil, s.newOpenAIAccountFailoverError(account, resp.StatusCode, resp.Header, respBody, upstreamMessage, shouldDisable, retryableOnSameAccount)
 			}
-			if isOpenAIUpstreamAccessStateError(upstreamMessage, respBody) {
+			if isOpenAIHTTPUpstreamAccessStateError(resp.StatusCode, upstreamMessage, respBody) {
 				return nil, newOpenAIUpstreamFailoverError(resp.StatusCode, resp.Header, respBody, upstreamMessage, retryableOnSameAccount)
 			}
 			return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode, ResponseBody: respBody, RetryableOnSameAccount: retryableOnSameAccount}
diff --git a/backend/internal/service/openai_apikey_health_breaker.go b/backend/internal/service/openai_apikey_health_breaker.go
index c898cf1124..65581ae3d2 100644
--- a/backend/internal/service/openai_apikey_health_breaker.go
+++ b/backend/internal/service/openai_apikey_health_breaker.go
@@ -124,15 +124,7 @@ func (s *RateLimitService) ObserveOpenAIAPIKeyHealthFailure(ctx context.Context,
 	return true
 }
 
-func (s *RateLimitService) ObserveOpenAIAPIKeyHealthSuccess(ctx context.Context, account *Account) {
-	if s == nil || s.openAIAPIKeyHealth == nil || s.settingService == nil || !isOpenAIAPIKeyHealthBreakerAccount(account) {
-		return
-	}
-	settings, err := s.settingService.GetOpenAIAPIKeyHealthBreakerSettings(ctx)
-	if err != nil || settings == nil || !settings.Enabled {
-		return
-	}
-	if err := s.openAIAPIKeyHealth.ResetOpenAIAPIKeyHealthFailures(ctx, account.ID); err != nil {
-		logger.L().Warn("openai.apikey_health_breaker_reset_failed", zap.Int64("account_id", account.ID), zap.Error(err))
-	}
+func (s *RateLimitService) ObserveOpenAIAPIKeyHealthSuccess(context.Context, *Account) {
+	// Health failures are accumulated in a rolling time window. A success does
+	// not reset that window and must not add a Redis round trip to the hot path.
 }
diff --git a/backend/internal/service/openai_apikey_health_breaker_test.go b/backend/internal/service/openai_apikey_health_breaker_test.go
index a6e7aaad00..4c58ed1b4a 100644
--- a/backend/internal/service/openai_apikey_health_breaker_test.go
+++ b/backend/internal/service/openai_apikey_health_breaker_test.go
@@ -13,10 +13,12 @@ import (
 
 type openAIAPIKeyHealthSettingRepo struct {
 	SettingRepository
-	value string
+	value    string
+	getCalls int
 }
 
 func (r *openAIAPIKeyHealthSettingRepo) GetValue(context.Context, string) (string, error) {
+	r.getCalls++
 	return r.value, nil
 }
 
@@ -35,7 +37,6 @@ func (r *openAIAPIKeyHealthAccountRepo) SetTempUnschedulable(_ context.Context,
 type openAIAPIKeyHealthCacheStub struct {
 	TempUnschedCache
 	recordCalls int
-	resetCalls  int
 	setCalls    int
 	tripped     bool
 }
@@ -45,11 +46,6 @@ func (c *openAIAPIKeyHealthCacheStub) RecordOpenAIAPIKeyHealthFailure(context.Co
 	return 3, c.tripped, nil
 }
 
-func (c *openAIAPIKeyHealthCacheStub) ResetOpenAIAPIKeyHealthFailures(context.Context, int64) error {
-	c.resetCalls++
-	return nil
-}
-
 func (c *openAIAPIKeyHealthCacheStub) SetTempUnsched(context.Context, int64, *TempUnschedState) error {
 	c.setCalls++
 	return nil
@@ -127,10 +123,11 @@ func TestOpenAIAPIKeyHealthBreakerTripsPersistedAndRuntimeState(t *testing.T) {
 	require.Contains(t, repo.reason, openAIAPIKeyHealthBreakerReason)
 }
 
-func TestOpenAIAPIKeyHealthSuccessResetsOnlyEligiblePoolAccount(t *testing.T) {
+func TestOpenAIAPIKeyHealthSuccessDoesNotTouchSettingsOrCache(t *testing.T) {
 	encoded, err := json.Marshal(OpenAIAPIKeyHealthBreakerSettings{Enabled: true, WindowMinutes: 1, FailureThreshold: 3, CooldownMinutes: 5})
 	require.NoError(t, err)
-	settings := NewSettingService(&openAIAPIKeyHealthSettingRepo{value: string(encoded)}, &config.Config{})
+	settingRepo := &openAIAPIKeyHealthSettingRepo{value: string(encoded)}
+	settings := NewSettingService(settingRepo, &config.Config{})
 	cache := &openAIAPIKeyHealthCacheStub{}
 	svc := NewRateLimitService(&openAIAPIKeyHealthAccountRepo{}, nil, &config.Config{}, nil, cache)
 	svc.SetSettingService(settings)
@@ -138,5 +135,6 @@ func TestOpenAIAPIKeyHealthSuccessResetsOnlyEligiblePoolAccount(t *testing.T) {
 
 	svc.ObserveOpenAIAPIKeyHealthSuccess(context.Background(), openAIHealthPoolAccount())
 	svc.ObserveOpenAIAPIKeyHealthSuccess(context.Background(), &Account{ID: 43, Platform: PlatformOpenAI, Type: AccountTypeAPIKey})
-	require.Equal(t, 1, cache.resetCalls)
+	require.Zero(t, settingRepo.getCalls)
+	require.Zero(t, cache.recordCalls)
 }
diff --git a/backend/internal/service/openai_codex_function_call_id_test.go b/backend/internal/service/openai_codex_function_call_id_test.go
index 1d798eec5e..18b2df3153 100644
--- a/backend/internal/service/openai_codex_function_call_id_test.go
+++ b/backend/internal/service/openai_codex_function_call_id_test.go
@@ -151,6 +151,28 @@ func TestFilterCodexInput_ExistingItemIDWinsOverLegacyCallIDMapping(t *testing.T
 	require.Equal(t, "call_shared", filtered[2].(map[string]any)["id"])
 }
 
+func TestFilterCodexInput_NormalizesCrossTurnLegacyCallReference(t *testing.T) {
+	input := []any{
+		map[string]any{"type": "item_reference", "id": "call_previous_turn"},
+	}
+
+	filtered := filterCodexInputWithOptions(input, codexInputFilterOptions{PreserveReferences: true})
+
+	require.Equal(t, "fc_previous_turn", filtered[0].(map[string]any)["id"])
+}
+
+func TestFilterCodexInput_PreservesNativeRemoteItemReferences(t *testing.T) {
+	for _, id := range []string{"fc_remote", "ctc_remote", "tsc_remote", "msg_remote", "rs_remote", "vendor_remote"} {
+		t.Run(id, func(t *testing.T) {
+			input := []any{map[string]any{"type": "item_reference", "id": id}}
+
+			filtered := filterCodexInputWithOptions(input, codexInputFilterOptions{PreserveReferences: true})
+
+			require.Equal(t, id, filtered[0].(map[string]any)["id"])
+		})
+	}
+}
+
 // TestFilterCodexInput_StripsItemIDFromAllToolCallInputTypes verifies that
 // item_* ids are stripped from all call-input types (not output types).
 func TestFilterCodexInput_StripsItemIDFromAllToolCallInputTypes(t *testing.T) {
diff --git a/backend/internal/service/openai_codex_transform.go b/backend/internal/service/openai_codex_transform.go
index bd24f29c66..fbd14ba967 100644
--- a/backend/internal/service/openai_codex_transform.go
+++ b/backend/internal/service/openai_codex_transform.go
@@ -1562,10 +1562,25 @@ func codexInputItemIDs(input []any) map[string]struct{} {
 	return itemIDs
 }
 
+func codexInputCallIDs(input []any) map[string]struct{} {
+	callIDs := make(map[string]struct{})
+	for _, rawItem := range input {
+		item, ok := rawItem.(map[string]any)
+		if !ok || !isCodexToolCallItemType(strings.TrimSpace(firstNonEmptyString(item["type"]))) {
+			continue
+		}
+		if callID := strings.TrimSpace(firstNonEmptyString(item["call_id"])); callID != "" {
+			callIDs[callID] = struct{}{}
+		}
+	}
+	return callIDs
+}
+
 func filterCodexInputWithOptions(input []any, opts codexInputFilterOptions) []any {
 	filtered := make([]any, 0, len(input))
 	referenceIDMappings := codexItemReferenceIDMappings(input, opts.PreserveCallIDs)
 	inputItemIDs := codexInputItemIDs(input)
+	inputCallIDs := codexInputCallIDs(input)
 	for _, item := range input {
 		m, ok := item.(map[string]any)
 		if !ok {
@@ -1629,8 +1644,14 @@ func filterCodexInputWithOptions(input []any, opts codexInputFilterOptions) []an
 			if id, ok := newItem["id"].(string); ok && strings.HasPrefix(strings.TrimSpace(id), "call_") {
 				trimmedID := strings.TrimSpace(id)
 				_, referencesExistingItem := inputItemIDs[trimmedID]
-				if normalizedID, mapped := referenceIDMappings[trimmedID]; mapped && !referencesExistingItem {
-					newItem["id"] = normalizedID
+				if !referencesExistingItem {
+					if normalizedID, mapped := referenceIDMappings[trimmedID]; mapped {
+						newItem["id"] = normalizedID
+					} else if _, hasSameTurnCall := inputCallIDs[trimmedID]; !hasSameTurnCall {
+						// A bare call_* reference is a legacy function-call identifier.
+						// Normalize it even when its call item lives in an earlier turn.
+						newItem["id"] = normalizeCodexCallID(trimmedID)
+					}
 				}
 			}
 			filtered = append(filtered, newItem)
diff --git a/backend/internal/service/openai_codex_transform_test.go b/backend/internal/service/openai_codex_transform_test.go
index 56be9570b0..7895b03cc3 100644
--- a/backend/internal/service/openai_codex_transform_test.go
+++ b/backend/internal/service/openai_codex_transform_test.go
@@ -127,6 +127,26 @@ func TestApplyCodexOAuthTransform_ToolContinuationNormalizesToolReferenceIDsOnly
 	require.Equal(t, "fc_1", second["call_id"])
 }
 
+func TestApplyCodexOAuthTransform_NormalizesIsolatedLegacyReferenceAcrossTurns(t *testing.T) {
+	reqBody := map[string]any{
+		"model": "gpt-5.2",
+		"input": []any{
+			map[string]any{"type": "item_reference", "id": "call_previous_turn"},
+			map[string]any{"type": "item_reference", "id": "fc_remote_item"},
+			map[string]any{"type": "item_reference", "id": "vendor_remote_item"},
+		},
+	}
+
+	applyCodexOAuthTransform(reqBody, false, false)
+
+	input, ok := reqBody["input"].([]any)
+	require.True(t, ok)
+	require.Len(t, input, 3)
+	require.Equal(t, "fc_previous_turn", input[0].(map[string]any)["id"])
+	require.Equal(t, "fc_remote_item", input[1].(map[string]any)["id"])
+	require.Equal(t, "vendor_remote_item", input[2].(map[string]any)["id"])
+}
+
 func TestApplyCodexOAuthTransform_BoundsLongCallIDsAndPreservesPairing(t *testing.T) {
 	suffix := strings.Repeat("z", 62)
 	for _, tc := range []struct {
diff --git a/backend/internal/service/openai_compact_fallback.go b/backend/internal/service/openai_compact_fallback.go
index 517a7e2e7b..389a4e8beb 100644
--- a/backend/internal/service/openai_compact_fallback.go
+++ b/backend/internal/service/openai_compact_fallback.go
@@ -1,7 +1,10 @@
 package service
 
 import (
+	"bytes"
+	"encoding/json"
 	"errors"
+	"io"
 	"net/http"
 	"strings"
 
@@ -89,11 +92,7 @@ func isOpenAICompactModelFailure(statusCode int, upstreamMsg string, upstreamBod
 		case "model_not_found", "model_not_available", "unsupported_model", "invalid_model":
 			return true
 		}
-		if strings.Contains(value, "model") && (strings.Contains(value, "not found") ||
-			strings.Contains(value, "does not exist") ||
-			strings.Contains(value, "unavailable") ||
-			strings.Contains(value, "unsupported") ||
-			strings.Contains(value, "not supported")) {
+		if isExplicitOpenAIModelAvailabilityMessage(value) {
 			return true
 		}
 	}
@@ -115,6 +114,121 @@ func isOpenAICompactModelFailure(statusCode int, upstreamMsg string, upstreamBod
 	return false
 }
 
+func isExplicitOpenAIModelAvailabilityMessage(value string) bool {
+	value = strings.ToLower(strings.TrimSpace(value))
+	if value == "" {
+		return false
+	}
+	for _, phrase := range []string{
+		"model not found",
+		"model does not exist",
+		"model is unavailable",
+		"model is not available",
+		"model is unsupported",
+		"model is not supported",
+		"unsupported model",
+	} {
+		if strings.Contains(value, phrase) {
+			return true
+		}
+	}
+	// OpenAI commonly identifies the missing model between the word "model"
+	// and the terminal availability phrase, for example: "The model `x` does
+	// not exist". Requiring the message to start with the model subject avoids
+	// treating unrelated feature errors such as "model output is not supported"
+	// as a signal to change models.
+	if strings.HasPrefix(value, "the model ") || strings.HasPrefix(value, "model ") {
+		return strings.Contains(value, " does not exist") ||
+			strings.Contains(value, " was not found") ||
+			strings.Contains(value, " is unavailable") ||
+			strings.Contains(value, " is not available")
+	}
+	return false
+}
+
+func openAICompactFallbackErrorResponse(resp *http.Response, signal *openAICompactFallbackSignal) (*http.Response, []byte) {
+	headers := make(http.Header)
+	if resp != nil {
+		headers = resp.Header.Clone()
+	}
+	if headers.Get("Content-Type") == "" {
+		headers.Set("Content-Type", "application/json")
+	}
+	payload := normalizeOpenAICompactFallbackHTTPErrorPayload(signal)
+	return &http.Response{
+		StatusCode: http.StatusBadRequest,
+		Header:     headers,
+		Body:       io.NopCloser(bytes.NewReader(payload)),
+	}, payload
+}
+
+func normalizeOpenAICompactFallbackHTTPErrorPayload(signal *openAICompactFallbackSignal) []byte {
+	if signal == nil {
+		return nil
+	}
+	payload := append([]byte(nil), signal.payload...)
+	var terminal struct {
+		Error    json.RawMessage `json:"error"`
+		Response struct {
+			Error json.RawMessage `json:"error"`
+		} `json:"response"`
+	}
+	if json.Unmarshal(payload, &terminal) != nil || len(bytes.TrimSpace(terminal.Response.Error)) == 0 ||
+		bytes.Equal(bytes.TrimSpace(terminal.Response.Error), []byte("null")) {
+		return payload
+	}
+	// Standard HTTP error handlers consume error.message/type/code. A streamed
+	// response.failed terminal nests the same object under response.error, so
+	// normalize only that envelope at the stream-to-HTTP boundary.
+	normalized, err := json.Marshal(struct {
+		Error json.RawMessage `json:"error"`
+	}{Error: terminal.Response.Error})
+	if err != nil {
+		return payload
+	}
+	return normalized
+}
+
+func (s *OpenAIGatewayService) appendOpenAICompactFallbackRetryOps(
+	c *gin.Context,
+	account *Account,
+	resp *http.Response,
+	payload []byte,
+	message string,
+	passthrough bool,
+) {
+	if account == nil {
+		return
+	}
+	statusCode := http.StatusBadRequest
+	requestID := ""
+	if resp != nil {
+		statusCode = resp.StatusCode
+		requestID = resp.Header.Get("x-request-id")
+	}
+	detail := ""
+	if s != nil && s.cfg != nil && s.cfg.Gateway.LogUpstreamErrorBody {
+		maxBytes := s.cfg.Gateway.LogUpstreamErrorBodyMaxBytes
+		if maxBytes <= 0 {
+			maxBytes = 2048
+		}
+		detail = truncateString(string(payload), maxBytes)
+	}
+	appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+		Platform:             account.Platform,
+		AccountID:            account.ID,
+		AccountName:          account.Name,
+		UpstreamStatusCode:   statusCode,
+		UpstreamRequestID:    requestID,
+		Passthrough:          passthrough,
+		Kind:                 "retry",
+		Reason:               "compact_model_fallback",
+		Message:              sanitizeUpstreamErrorMessage(strings.TrimSpace(message)),
+		Detail:               detail,
+		UpstreamResponseBody: detail,
+	})
+}
+
 // prepareOpenAICompactFallbackRetry returns a body for one safe, same-account
 // retry. Callers invoke it only before any downstream response has been
 // written; it changes the model and deliberately leaves path, trigger, and
@@ -164,6 +278,7 @@ func (s *OpenAIGatewayService) applyOpenAIPassthroughCompactFallbackFromSignal(
 	if !retry {
 		return body, "", false
 	}
+	s.appendOpenAICompactFallbackRetryOps(c, account, resp, signal.payload, signal.message, true)
 	if resp != nil && resp.Body != nil {
 		_ = resp.Body.Close()
 	}
diff --git a/backend/internal/service/openai_compact_fallback_test.go b/backend/internal/service/openai_compact_fallback_test.go
index 944f7e1cfd..2e4c7050eb 100644
--- a/backend/internal/service/openai_compact_fallback_test.go
+++ b/backend/internal/service/openai_compact_fallback_test.go
@@ -3,11 +3,14 @@ package service
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/gin-gonic/gin"
@@ -138,6 +141,29 @@ func TestPrepareOpenAICompactFallbackRetryDoesNotHideSpecificBusinessFailure(t *
 	require.Equal(t, body, retryBody)
 }
 
+func TestIsOpenAICompactModelFailureRequiresExplicitModelAvailabilityMessage(t *testing.T) {
+	tests := []struct {
+		name    string
+		message string
+		want    bool
+	}{
+		{name: "explicit unsupported model", message: "The requested model is not supported", want: true},
+		{name: "named missing model", message: "The model `gpt-5.5` does not exist", want: true},
+		{name: "unsupported model code-like message", message: "unsupported model: gpt-5.5", want: true},
+		{name: "unsupported model feature", message: "This model output format is not supported", want: false},
+		{name: "unsupported parameter for model", message: "Parameter tools is not supported for this model", want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require.Equal(t, tt.want, isOpenAICompactModelFailure(
+				http.StatusBadRequest,
+				tt.message,
+				[]byte(`{"error":{"message":`+strconv.Quote(tt.message)+`}}`),
+			))
+		})
+	}
+}
+
 func TestPrepareOpenAICompactFallbackRetrySkipsSameModel(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	svc := &OpenAIGatewayService{cfg: &config.Config{Gateway: config.GatewayConfig{OpenAICompactModel: "gpt-5.5"}}}
@@ -191,6 +217,14 @@ func TestOpenAIGatewayForwardRetriesExplicitNativeCompactHTTPFailureOnce(t *test
 	require.True(t, HasCompactionTriggerInInput(upstream.bodies[1]))
 	require.Equal(t, upstream.requests[0].URL.Path, upstream.requests[1].URL.Path)
 	require.NotContains(t, upstream.requests[1].URL.Path, "/compact")
+	rawEvents, ok := c.Get(OpsUpstreamErrorsKey)
+	require.True(t, ok)
+	events, ok := rawEvents.([]*OpsUpstreamErrorEvent)
+	require.True(t, ok)
+	require.Len(t, events, 1)
+	require.Equal(t, "retry", events[0].Kind)
+	require.Equal(t, "compact_model_fallback", events[0].Reason)
+	require.Equal(t, http.StatusBadRequest, events[0].UpstreamStatusCode)
 }
 
 func TestOpenAIGatewayForwardRetriesExplicitNativeCompactSSEFailureBeforeOutput(t *testing.T) {
@@ -309,4 +343,63 @@ func TestOpenAIGatewayForwardDoesNotRecurseWhenCompactFallbackAlsoFails(t *testi
 	require.Len(t, upstream.bodies, 2)
 	require.Equal(t, "gpt-5.5", gjson.GetBytes(upstream.bodies[0], "model").String())
 	require.Equal(t, "gpt-5.4", gjson.GetBytes(upstream.bodies[1], "model").String())
+	var compactSignal *openAICompactFallbackSignal
+	require.False(t, errors.As(err, &compactSignal))
+	require.Equal(t, http.StatusBadRequest, recorder.Code)
+	require.Contains(t, recorder.Body.String(), "model not found")
+	rawEvents, ok := c.Get(OpsUpstreamErrorsKey)
+	require.True(t, ok)
+	events, ok := rawEvents.([]*OpsUpstreamErrorEvent)
+	require.True(t, ok)
+	require.Len(t, events, 2)
+	require.Equal(t, "retry", events[0].Kind)
+	require.Equal(t, "compact_model_fallback", events[0].Reason)
+	require.Equal(t, "http_error", events[1].Kind)
+}
+
+func TestOpenAIPassthroughCompactFallbackSecondStreamFailureUsesStandardErrorPath(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	body := []byte(`{"model":"gpt-5.5","stream":true,"input":[{"type":"compaction_trigger"}]}`)
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", nil)
+	c.Request.Header.Set("Content-Type", "application/json")
+	MarkOpenAINativeCompactionV2(c)
+
+	failed := "event: response.failed\n" +
+		`data: {"type":"response.failed","response":{"status":"failed","error":{"code":"context_length_exceeded","message":"context window exceeded"}}}` + "\n\n"
+	upstream := &httpUpstreamRecorder{responses: []*http.Response{
+		{StatusCode: http.StatusOK, Header: http.Header{"Content-Type": []string{"text/event-stream"}}, Body: io.NopCloser(strings.NewReader(failed))},
+		{StatusCode: http.StatusOK, Header: http.Header{"Content-Type": []string{"text/event-stream"}}, Body: io.NopCloser(strings.NewReader(failed))},
+	}}
+	svc := &OpenAIGatewayService{
+		cfg:          &config.Config{Gateway: config.GatewayConfig{OpenAICompactModel: "gpt-5.4"}},
+		httpUpstream: upstream,
+	}
+	account := &Account{
+		ID: 1, Name: "openai-oauth", Platform: PlatformOpenAI, Type: AccountTypeOAuth, Concurrency: 1,
+		Credentials: map[string]any{"access_token": "oauth-token", "chatgpt_account_id": "chatgpt-account"},
+		Status:      StatusActive, Schedulable: true,
+	}
+
+	result, err := svc.forwardOpenAIPassthrough(
+		context.Background(), c, account, body, body, "gpt-5.5", false, nil, true, time.Now(),
+	)
+
+	require.Error(t, err)
+	require.Nil(t, result)
+	require.Len(t, upstream.bodies, 2)
+	var compactSignal *openAICompactFallbackSignal
+	require.False(t, errors.As(err, &compactSignal))
+	require.Equal(t, http.StatusBadRequest, recorder.Code)
+	require.Contains(t, recorder.Body.String(), "context window exceeded")
+	rawEvents, ok := c.Get(OpsUpstreamErrorsKey)
+	require.True(t, ok)
+	events, ok := rawEvents.([]*OpsUpstreamErrorEvent)
+	require.True(t, ok)
+	require.Len(t, events, 2)
+	require.Equal(t, "retry", events[0].Kind)
+	require.Equal(t, "compact_model_fallback", events[0].Reason)
+	require.Equal(t, "http_error", events[1].Kind)
+	require.True(t, events[1].Passthrough)
 }
diff --git a/backend/internal/service/openai_cyber_session_block.go b/backend/internal/service/openai_cyber_session_block.go
index 797e746561..44c3ece444 100644
--- a/backend/internal/service/openai_cyber_session_block.go
+++ b/backend/internal/service/openai_cyber_session_block.go
@@ -21,6 +21,8 @@ type CyberSessionBlockStore interface {
 	FindCyberSessionBlocked(ctx context.Context, keys []string) (string, error)
 }
 
+const cyberSessionTranscriptLookupOverflowBlockKey = "transcript_lookup_limit_exceeded"
+
 // CyberSessionExplicitBlockKey returns an inexpensive exact key when the
 // client supplies a stable session signal.
 func CyberSessionExplicitBlockKey(apiKeyID int64, c *gin.Context, body []byte) string {
@@ -142,7 +144,13 @@ func (s *OpenAIGatewayService) FindCyberSessionBlockedForRequest(ctx context.Con
 	if !active {
 		return ""
 	}
-	keys := CyberSessionTranscriptLookupKeys(apiKeyID, body)
+	transcript := deriveOpenAICyberTranscriptBlockKeys(apiKeyID, body)
+	if transcript.lookupKeysTruncated {
+		// Once the coarse scope is active, silently dropping old candidates would
+		// let a blocked client evade prefix matching by appending dummy items.
+		return cyberSessionTranscriptLookupOverflowBlockKey
+	}
+	keys := transcript.lookupKeys
 	if len(keys) == 0 {
 		return ""
 	}
diff --git a/backend/internal/service/openai_cyber_session_block_test.go b/backend/internal/service/openai_cyber_session_block_test.go
index 7080450042..aff46df25d 100644
--- a/backend/internal/service/openai_cyber_session_block_test.go
+++ b/backend/internal/service/openai_cyber_session_block_test.go
@@ -2,8 +2,10 @@ package service
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"net/http/httptest"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -75,11 +77,32 @@ func TestCyberTranscriptBlockKeysWebSocketResponseCreate(t *testing.T) {
 	require.Len(t, CyberSessionTranscriptBlockKeys(88, body), 2)
 }
 
+func TestCyberTranscriptLookupKeysAreBoundedAndKeepNewestOrder(t *testing.T) {
+	messages := make([]map[string]string, maxOpenAICyberTranscriptLookupKeys+44)
+	for i := range messages {
+		messages[i] = map[string]string{"role": "user", "content": "message-" + strconv.Itoa(i)}
+	}
+	body, err := json.Marshal(map[string]any{"messages": messages})
+	require.NoError(t, err)
+
+	keys := CyberSessionTranscriptLookupKeys(77, body)
+	require.Len(t, keys, maxOpenAICyberTranscriptLookupKeys)
+
+	firstRetainedBody, err := json.Marshal(map[string]any{"messages": messages[:45]})
+	require.NoError(t, err)
+	firstRetainedPrefix := CyberSessionTranscriptLookupKeys(77, firstRetainedBody)
+	require.Equal(t, firstRetainedPrefix[len(firstRetainedPrefix)-1], keys[0])
+
+	fullKey := CyberSessionTranscriptBlockKeys(77, body)[0]
+	require.Equal(t, fullKey, keys[len(keys)-1])
+}
+
 // --- fakes ---
 
 type fakeCyberBlockStore struct {
-	blocked map[string]bool
-	scopes  map[string]bool
+	blocked   map[string]bool
+	scopes    map[string]bool
+	findCalls int
 }
 
 var _ CyberSessionBlockStore = (*fakeCyberBlockStore)(nil)
@@ -105,6 +128,7 @@ func (f *fakeCyberBlockStore) IsCyberSessionScopeActive(_ context.Context, scope
 }
 
 func (f *fakeCyberBlockStore) FindCyberSessionBlocked(_ context.Context, keys []string) (string, error) {
+	f.findCalls++
 	for _, key := range keys {
 		if f.blocked[key] {
 			return key, nil
@@ -271,6 +295,34 @@ func TestFindCyberSessionBlockedForRequestUsesScopeForTranscript(t *testing.T) {
 	require.Equal(t, blockKey, svc.FindCyberSessionBlockedForRequest(ctx, 9, nextCtx, nextBody, clientIP, "Codex CLI 1.2.4"))
 }
 
+func TestFindCyberSessionBlockedForRequestFailsClosedOnScopedTranscriptOverflow(t *testing.T) {
+	settingSvc := &SettingService{settingRepo: &fakeSettingRepo{vals: map[string]string{
+		SettingKeyCyberSessionBlockEnabled:    "true",
+		SettingKeyCyberSessionBlockTTLSeconds: "60",
+	}}}
+	combo := &comboCacheAndStore{}
+	svc := &OpenAIGatewayService{cache: combo, settingService: settingSvc}
+	ctx := context.Background()
+	const apiKeyID = int64(9)
+	const clientIP = "203.0.113.20"
+	const userAgent = "Codex CLI 1.2.3"
+
+	messages := make([]map[string]string, maxOpenAICyberTranscriptLookupKeys+1)
+	for i := range messages {
+		messages[i] = map[string]string{"role": "user", "content": "message-" + strconv.Itoa(i)}
+	}
+	body, err := json.Marshal(map[string]any{"messages": messages})
+	require.NoError(t, err)
+	c, _ := newCyberBlockTestCtx(nil, string(body))
+	require.Empty(t, svc.FindCyberSessionBlockedForRequest(ctx, apiKeyID, c, body, clientIP, userAgent),
+		"overflow alone must not bypass the scope gate")
+	combo.store.scopes = map[string]bool{CyberSessionScopeKey(apiKeyID, clientIP, userAgent): true}
+
+	require.Equal(t, cyberSessionTranscriptLookupOverflowBlockKey,
+		svc.FindCyberSessionBlockedForRequest(ctx, apiKeyID, c, body, clientIP, userAgent))
+	require.Zero(t, combo.store.findCalls, "overflow must not issue an unbounded Redis lookup")
+}
+
 func TestCyberSessionScopeKeyNormalizesUserAgentVersion(t *testing.T) {
 	base := CyberSessionScopeKey(7, "203.0.113.10", "Codex CLI 1.2.3")
 	require.NotEmpty(t, base)
diff --git a/backend/internal/service/openai_cyber_transcript.go b/backend/internal/service/openai_cyber_transcript.go
index 1314d54c51..b286c04769 100644
--- a/backend/internal/service/openai_cyber_transcript.go
+++ b/backend/internal/service/openai_cyber_transcript.go
@@ -11,10 +11,15 @@ import (
 )
 
 type openAICyberTranscriptBlockKeys struct {
-	lookupKeys       []string
-	preLatestUserKey string
+	lookupKeys          []string
+	preLatestUserKey    string
+	lookupKeysTruncated bool
 }
 
+// Bound the Redis lookup work for a single request while retaining the most
+// recent transcript prefixes, where a continuation is most likely to match.
+const maxOpenAICyberTranscriptLookupKeys = 256
+
 // deriveOpenAICyberTranscriptBlockKeys returns cumulative semantic-history
 // hashes plus the context key immediately before the latest user turn. The
 // context key requires model-generated history so shared first-turn templates
@@ -53,8 +58,11 @@ func deriveOpenAICyberTranscriptBlockKeys(apiKeyID int64, body []byte) openAICyb
 			return openAICyberTranscriptBlockKeys{}
 		}
 		result := openAICyberTranscriptBlockKeys{
-			lookupKeys: make([]string, 0, int(sequence.Get("#").Int())),
+			lookupKeys: make([]string, 0, maxOpenAICyberTranscriptLookupKeys),
 		}
+		nextLookupKey := 0
+		lookupKeysRotated := false
+		lastLookupKey := ""
 		// This is an entropy heuristic, not provenance proof: authenticated
 		// server-side history would be required to distinguish fixed few-shot
 		// assistant items perfectly.
@@ -71,17 +79,31 @@ func deriveOpenAICyberTranscriptBlockKeys(apiKeyID int64, body []byte) openAICyb
 			if strings.TrimSpace(canonical) == "" {
 				return true
 			}
-			if openAICyberTranscriptItemStartsUserTurn(item) && hasModelGeneratedItem && len(result.lookupKeys) > 0 {
-				result.preLatestUserKey = result.lookupKeys[len(result.lookupKeys)-1]
+			if openAICyberTranscriptItemStartsUserTurn(item) && hasModelGeneratedItem && lastLookupKey != "" {
+				result.preLatestUserKey = lastLookupKey
 			}
 			_, _ = h.Write([]byte("|item="))
 			_, _ = h.Write([]byte(canonical))
-			result.lookupKeys = append(result.lookupKeys, hex.EncodeToString(h.Sum(nil)))
+			lastLookupKey = hex.EncodeToString(h.Sum(nil))
+			if len(result.lookupKeys) < maxOpenAICyberTranscriptLookupKeys {
+				result.lookupKeys = append(result.lookupKeys, lastLookupKey)
+			} else {
+				result.lookupKeys[nextLookupKey] = lastLookupKey
+				nextLookupKey = (nextLookupKey + 1) % maxOpenAICyberTranscriptLookupKeys
+				lookupKeysRotated = true
+				result.lookupKeysTruncated = true
+			}
 			if openAICyberTranscriptItemIsModelGenerated(item) {
 				hasModelGeneratedItem = true
 			}
 			return true
 		})
+		if lookupKeysRotated {
+			ordered := make([]string, 0, len(result.lookupKeys))
+			ordered = append(ordered, result.lookupKeys[nextLookupKey:]...)
+			ordered = append(ordered, result.lookupKeys[:nextLookupKey]...)
+			result.lookupKeys = ordered
+		}
 		return result
 	}
 
diff --git a/backend/internal/service/openai_embeddings.go b/backend/internal/service/openai_embeddings.go
index ef0c88b2d7..366e11a22f 100644
--- a/backend/internal/service/openai_embeddings.go
+++ b/backend/internal/service/openai_embeddings.go
@@ -140,7 +140,7 @@ func (s *OpenAIGatewayService) ForwardEmbeddings(
 			if account.IsOpenAIOAuth() && resp.StatusCode == http.StatusTooManyRequests {
 				return nil, s.newOpenAIAccountFailoverError(account, resp.StatusCode, resp.Header, respBody, upstreamMsg, shouldDisable, retryableOnSameAccount)
 			}
-			if isOpenAIUpstreamAccessStateError(upstreamMsg, respBody) {
+			if isOpenAIHTTPUpstreamAccessStateError(resp.StatusCode, upstreamMsg, respBody) {
 				return nil, newOpenAIUpstreamFailoverError(resp.StatusCode, resp.Header, respBody, upstreamMsg, retryableOnSameAccount)
 			}
 			return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode, ResponseBody: respBody, RetryableOnSameAccount: retryableOnSameAccount}
diff --git a/backend/internal/service/openai_gateway_apikey_item_id_test.go b/backend/internal/service/openai_gateway_apikey_item_id_test.go
index 9605a0acee..e3a93bebb3 100644
--- a/backend/internal/service/openai_gateway_apikey_item_id_test.go
+++ b/backend/internal/service/openai_gateway_apikey_item_id_test.go
@@ -258,7 +258,7 @@ func TestSanitizeOpenAIResponsesInputItemIDs_AllocationGrowthIsLinear(t *testing
 		"10x more input items must not cause quadratic whole-body allocation growth")
 }
 
-func TestNormalizeOpenAIResponsesWebSocketCompatibilityBodyClosesInvalidIDReferences(t *testing.T) {
+func TestNormalizeOpenAIResponsesWebSocketCompatibilityBodyPreservesOpaqueReferences(t *testing.T) {
 	body := []byte(`{"type":"response.create","input":[
 		{"type":"custom_tool_call","id":"ctc_call","call_id":"call_custom","name":"apply_patch","input":"patch"},
 		{"type":"custom_tool_call_output","id":"ctco_bad","call_id":"call_custom","output":"done"},
@@ -275,11 +275,12 @@ func TestNormalizeOpenAIResponsesWebSocketCompatibilityBodyClosesInvalidIDRefere
 
 			require.NoError(t, err)
 			require.True(t, changed)
-			require.Len(t, gjson.GetBytes(normalized, "input").Array(), 3)
+			require.Len(t, gjson.GetBytes(normalized, "input").Array(), 4)
 			require.Equal(t, "ctc_call", gjson.GetBytes(normalized, "input.0.id").String())
 			require.Equal(t, "call_custom", gjson.GetBytes(normalized, "input.1.call_id").String())
 			require.False(t, gjson.GetBytes(normalized, "input.1.id").Exists())
-			require.Equal(t, "item_future", gjson.GetBytes(normalized, "input.2.id").String())
+			require.Equal(t, "ctco_bad", gjson.GetBytes(normalized, "input.2.id").String())
+			require.Equal(t, "item_future", gjson.GetBytes(normalized, "input.3.id").String())
 
 			second, changedAgain, err := normalizeOpenAIResponsesWebSocketCompatibilityBody(normalized, &Account{
 				Platform: PlatformOpenAI,
diff --git a/backend/internal/service/openai_gateway_forward.go b/backend/internal/service/openai_gateway_forward.go
index 1d2c9f5f39..99d89a7fac 100644
--- a/backend/internal/service/openai_gateway_forward.go
+++ b/backend/internal/service/openai_gateway_forward.go
@@ -59,21 +59,10 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	// 在分流到 passthrough / Codex transform / 原生 ChatCompletions 之前统一修正
 	// 显式为 null 的工具 Schema type，否则 upstream 的 400 会被归一成可重试的 502，
 	// 同一份坏定义在账号池里反复重放。
-	if shouldSanitizeOpenAIResponsesToolSchemas(account.Platform) {
-		sanitizedToolBody, toolSchemaSanitized, toolSchemaErr := sanitizeOpenAIResponsesToolParameterTypes(body)
-		if toolSchemaErr != nil {
-			return nil, fmt.Errorf("sanitize OpenAI Responses tool parameters: %w", toolSchemaErr)
-		}
-		if toolSchemaSanitized {
-			body = sanitizedToolBody
-		}
-		patternSanitizedBody, patternSanitized, patternErr := sanitizeOpenAIResponsesToolSchemaPatterns(body)
-		if patternErr != nil {
-			return nil, fmt.Errorf("sanitize OpenAI Responses tool schema patterns: %w", patternErr)
-		}
-		if patternSanitized {
-			body = patternSanitizedBody
-		}
+	if sanitizedToolBody, toolSchemaSanitized, toolSchemaErr := sanitizeOpenAIResponsesToolSchemasForPlatform(body, account.Platform); toolSchemaErr != nil {
+		return nil, toolSchemaErr
+	} else if toolSchemaSanitized {
+		body = sanitizedToolBody
 	}
 	if account.IsOpenAIOAuthLike() {
 		reasoningBody, reasoningChanged, reasoningErr := normalizeOpenAIResponsesReasoningMode(body)
@@ -1015,6 +1004,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 			if retryBody, fallbackModel, retry := s.prepareOpenAICompactFallbackRetry(
 				c, account, requestedModel, body, resp.StatusCode, upstreamMsg, respBody, compactModelFallbackRetried,
 			); retry {
+				s.appendOpenAICompactFallbackRetryOps(c, account, resp, respBody, upstreamMsg, false)
 				fromModel := strings.TrimSpace(gjson.GetBytes(body, "model").String())
 				body = retryBody
 				requestView = newOpenAIRequestView(body)
@@ -1082,6 +1072,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 					if retryBody, fallbackModel, retry := s.prepareOpenAICompactFallbackRetry(
 						c, account, requestedModel, body, http.StatusBadRequest, signal.message, signal.payload, compactModelFallbackRetried,
 					); retry {
+						s.appendOpenAICompactFallbackRetryOps(c, account, resp, signal.payload, signal.message, false)
 						body = retryBody
 						requestView = newOpenAIRequestView(body)
 						upstreamModel = fallbackModel
@@ -1089,6 +1080,27 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 						SetOpsUpstreamModel(c, fallbackModel)
 						continue
 					}
+					if resp.Body != nil {
+						_ = resp.Body.Close()
+					}
+					compactResp, compactBody := openAICompactFallbackErrorResponse(resp, signal)
+					if s.shouldFailoverOpenAIUpstreamResponse(compactResp.StatusCode, signal.message, compactBody) {
+						appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+							Platform:           account.Platform,
+							AccountID:          account.ID,
+							AccountName:        account.Name,
+							UpstreamStatusCode: compactResp.StatusCode,
+							UpstreamRequestID:  compactResp.Header.Get("x-request-id"),
+							Kind:               "failover",
+							Message:            signal.message,
+						})
+						shouldDisable := s.handleFailoverSideEffects(ctx, compactResp, account, compactBody, upstreamModel)
+						return nil, s.newOpenAIAccountFailoverError(
+							account, compactResp.StatusCode, compactResp.Header, compactBody, signal.message, shouldDisable,
+							!shouldDisable && account.IsPoolMode() && (account.IsPoolModeRetryableStatus(compactResp.StatusCode) || isOpenAITransientProcessingError(compactResp.StatusCode, signal.message, compactBody)),
+						)
+					}
+					return s.handleErrorResponse(ctx, compactResp, c, account, body, resolveOpenAIErrorSchedulingModel(billingModel, upstreamModel))
 				}
 				return nil, err
 			}
diff --git a/backend/internal/service/openai_gateway_passthrough.go b/backend/internal/service/openai_gateway_passthrough.go
index 06653094ce..f5c8cfe106 100644
--- a/backend/internal/service/openai_gateway_passthrough.go
+++ b/backend/internal/service/openai_gateway_passthrough.go
@@ -377,6 +377,7 @@ func (s *OpenAIGatewayService) forwardOpenAIPassthrough(
 			if retryBody, fallbackModel, retry := s.prepareOpenAICompactFallbackRetry(
 				c, account, requestedModel, body, resp.StatusCode, upstreamMsg, probeBody, compactModelFallbackRetried,
 			); retry {
+				s.appendOpenAICompactFallbackRetryOps(c, account, resp, probeBody, upstreamMsg, true)
 				fromModel := strings.TrimSpace(gjson.GetBytes(body, "model").String())
 				body = retryBody
 				upstreamPassthroughModel = fallbackModel
@@ -425,6 +426,14 @@ func (s *OpenAIGatewayService) forwardOpenAIPassthrough(
 					compactModelFallbackRetried = true
 					continue
 				}
+				if signal, ok := asOpenAICompactFallbackSignal(handleErr); ok {
+					_ = resp.Body.Close()
+					compactResp, compactBody := openAICompactFallbackErrorResponse(resp, signal)
+					if shouldFailoverOpenAIPassthroughResponse(account, compactResp.StatusCode, compactBody) {
+						return nil, s.handleFailoverErrorResponsePassthrough(ctx, compactResp, c, account, body, compactBody)
+					}
+					return nil, s.handleErrorResponsePassthrough(ctx, compactResp, c, account, body, compactBody)
+				}
 				_ = resp.Body.Close()
 				return nil, handleErr
 			}
@@ -444,6 +453,14 @@ func (s *OpenAIGatewayService) forwardOpenAIPassthrough(
 					compactModelFallbackRetried = true
 					continue
 				}
+				if signal, ok := asOpenAICompactFallbackSignal(handleErr); ok {
+					_ = resp.Body.Close()
+					compactResp, compactBody := openAICompactFallbackErrorResponse(resp, signal)
+					if shouldFailoverOpenAIPassthroughResponse(account, compactResp.StatusCode, compactBody) {
+						return nil, s.handleFailoverErrorResponsePassthrough(ctx, compactResp, c, account, body, compactBody)
+					}
+					return nil, s.handleErrorResponsePassthrough(ctx, compactResp, c, account, body, compactBody)
+				}
 				_ = resp.Body.Close()
 				return nil, handleErr
 			}
@@ -713,7 +730,7 @@ func shouldFailoverOpenAIPassthroughResponse(account *Account, statusCode int, r
 	if isOpenAIContextWindowError("", responseBody) {
 		return false
 	}
-	if isOpenAIUpstreamAccessStateError("", responseBody) {
+	if isOpenAIHTTPUpstreamAccessStateError(statusCode, "", responseBody) {
 		return true
 	}
 	if isOpenAIRequestBodyTooLargeError(statusCode, "", responseBody) {
@@ -1520,7 +1537,14 @@ func (s *OpenAIGatewayService) handleOpenAIStreamTerminalAccountSideEffects(
 		if c != nil && c.Request != nil {
 			ctx = c.Request.Context()
 		}
-		return statusCode, s.handleOpenAIAccountUpstreamError(ctx, account, statusCode, headers, payload)
+		accountHeaders := headers
+		if statusCode == http.StatusTooManyRequests {
+			// The enclosing HTTP response succeeded. Its quota snapshot describes
+			// normal account state and must not become the reset for a semantic 429
+			// carried by a stream terminal event.
+			accountHeaders = nil
+		}
+		return statusCode, s.handleOpenAIAccountUpstreamError(ctx, account, statusCode, accountHeaders, payload)
 	default:
 		return statusCode, false
 	}
diff --git a/backend/internal/service/openai_gateway_request_body.go b/backend/internal/service/openai_gateway_request_body.go
index e07e041ced..79ee4c4284 100644
--- a/backend/internal/service/openai_gateway_request_body.go
+++ b/backend/internal/service/openai_gateway_request_body.go
@@ -1033,17 +1033,11 @@ func normalizeOpenAIResponsesWebSocketCompatibilityBody(body []byte, account *Ac
 			changed = true
 		}
 	}
-	if account != nil && shouldSanitizeOpenAIResponsesToolSchemas(account.Platform) {
-		if toolBody, toolChanged, err := sanitizeOpenAIResponsesToolParameterTypes(normalized); err != nil {
-			return body, false, fmt.Errorf("normalize websocket tool parameter types: %w", err)
-		} else if toolChanged {
-			normalized = toolBody
-			changed = true
-		}
-		if patternBody, patternChanged, err := sanitizeOpenAIResponsesToolSchemaPatterns(normalized); err != nil {
-			return body, false, fmt.Errorf("normalize websocket tool schema patterns: %w", err)
-		} else if patternChanged {
-			normalized = patternBody
+	if account != nil {
+		if schemaBody, schemaChanged, err := sanitizeOpenAIResponsesToolSchemasForPlatform(normalized, account.Platform); err != nil {
+			return body, false, fmt.Errorf("normalize websocket tool schemas: %w", err)
+		} else if schemaChanged {
+			normalized = schemaBody
 			changed = true
 		}
 	}
diff --git a/backend/internal/service/openai_gateway_response_flush_test.go b/backend/internal/service/openai_gateway_response_flush_test.go
index 16483567ad..fe6e3ea6b2 100644
--- a/backend/internal/service/openai_gateway_response_flush_test.go
+++ b/backend/internal/service/openai_gateway_response_flush_test.go
@@ -441,6 +441,62 @@ func TestOpenAIResponseFlush_FailedAndErrorEventsFlushAtBoundaries(t *testing.T)
 	})
 }
 
+func TestOpenAIResponseFlush_BareErrorFollowedByCompletedUsesCompletedTerminal(t *testing.T) {
+	body := "data: {\"type\":\"error\",\"error\":{\"code\":\"transient\",\"message\":\"retrying\"}}\n\n" +
+		"data: {\"type\":\"response.completed\",\"response\":{\"id\":\"resp_recovered\",\"status\":\"completed\",\"output\":[],\"usage\":{\"input_tokens\":7,\"output_tokens\":3}}}\n\n"
+	recorder := newOpenAIResponseFlushRecorder()
+
+	result, err := runOpenAIResponseFlushTest(recorder, io.NopCloser(strings.NewReader(body)), config.GatewayConfig{})
+
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, 7, result.usage.InputTokens)
+	require.Equal(t, 3, result.usage.OutputTokens)
+	gotBody, _ := recorder.snapshot()
+	require.NotContains(t, gotBody, `"type":"error"`)
+	require.NotContains(t, gotBody, `"type":"response.failed"`)
+	require.Contains(t, gotBody, `"type":"response.completed"`)
+}
+
+func TestOpenAIResponseFlush_CompatibleAPIKeyDoesNotUseCodexBareErrorSynthesis(t *testing.T) {
+	body := "data: {\"type\":\"error\",\"error\":{\"code\":\"provider_error\",\"message\":\"provider failed\"}}\n\n"
+	recorder := newOpenAIResponseFlushRecorder()
+	account := &Account{ID: 2, Platform: PlatformOpenAI, Type: AccountTypeAPIKey}
+
+	result, err := runOpenAIResponseFlushTestWithAccount(recorder, io.NopCloser(strings.NewReader(body)), config.GatewayConfig{}, account)
+
+	require.Error(t, err)
+	require.NotNil(t, result)
+	gotBody, _ := recorder.snapshot()
+	require.Contains(t, gotBody, `"type":"error"`)
+	require.NotContains(t, gotBody, `"type":"response.failed"`)
+}
+
+func TestOpenAIResponseFlush_RecentBareErrorAllowsCompletedBeforeIdleTimeout(t *testing.T) {
+	reader, writer := io.Pipe()
+	defer func() { _ = writer.Close() }()
+	recorder := newOpenAIResponseFlushRecorder()
+	resultCh, errCh := runOpenAIResponseFlushTestAsync(recorder, reader, config.GatewayConfig{StreamDataIntervalTimeout: 1})
+
+	// Place the bare error shortly before the first ticker firing. It is fresh
+	// data, so the ticker must leave the stream open for an authoritative event.
+	time.Sleep(700 * time.Millisecond)
+	_, err := io.WriteString(writer, "data: {\"type\":\"error\",\"error\":{\"code\":\"transient\",\"message\":\"retrying\"}}\n\n")
+	require.NoError(t, err)
+	time.Sleep(500 * time.Millisecond)
+	_, err = io.WriteString(writer, "data: {\"type\":\"response.completed\",\"response\":{\"id\":\"resp_late\",\"status\":\"completed\",\"output\":[],\"usage\":{\"input_tokens\":5,\"output_tokens\":1}}}\n\n")
+	require.NoError(t, err)
+	require.NoError(t, writer.Close())
+
+	require.NoError(t, <-errCh)
+	result := <-resultCh
+	require.NotNil(t, result)
+	require.Equal(t, 5, result.usage.InputTokens)
+	gotBody, _ := recorder.snapshot()
+	require.Contains(t, gotBody, `"type":"response.completed"`)
+	require.NotContains(t, gotBody, `"type":"response.failed"`)
+}
+
 func TestOpenAIResponseFlush_BareErrorTimeoutSynthesizesFailed(t *testing.T) {
 	tests := []struct {
 		name string
@@ -534,6 +590,10 @@ func TestOpenAIResponseFlush_ClientDisconnectStillDrainsUsage(t *testing.T) {
 }
 
 func runOpenAIResponseFlushTest(recorder *openAIResponseFlushRecorder, body io.ReadCloser, gatewayCfg config.GatewayConfig) (*openaiStreamingResult, error) {
+	return runOpenAIResponseFlushTestWithAccount(recorder, body, gatewayCfg, &Account{ID: 1, Platform: PlatformOpenAI, Type: AccountTypeOAuth})
+}
+
+func runOpenAIResponseFlushTestWithAccount(recorder *openAIResponseFlushRecorder, body io.ReadCloser, gatewayCfg config.GatewayConfig, account *Account) (*openaiStreamingResult, error) {
 	gin.SetMode(gin.TestMode)
 	c, _ := gin.CreateTestContext(recorder)
 	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", nil)
@@ -546,7 +606,7 @@ func runOpenAIResponseFlushTest(recorder *openAIResponseFlushRecorder, body io.R
 		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
 		Body:       body,
 	}
-	return svc.handleStreamingResponse(context.Background(), resp, c, &Account{ID: 1, Platform: PlatformOpenAI}, time.Now(), "gpt-5", "gpt-5")
+	return svc.handleStreamingResponse(context.Background(), resp, c, account, time.Now(), "gpt-5", "gpt-5")
 }
 
 func runOpenAIResponseFlushTestAsync(recorder *openAIResponseFlushRecorder, body io.ReadCloser, gatewayCfg config.GatewayConfig) (<-chan *openaiStreamingResult, <-chan error) {
diff --git a/backend/internal/service/openai_gateway_response_handling.go b/backend/internal/service/openai_gateway_response_handling.go
index 45d08e86f3..2675ebb995 100644
--- a/backend/internal/service/openai_gateway_response_handling.go
+++ b/backend/internal/service/openai_gateway_response_handling.go
@@ -251,7 +251,7 @@ func (s *OpenAIGatewayService) handleStreamingResponseWithReasoning(ctx context.
 	capacityFailoverSuppressedLogged := false
 	failedMessage := ""
 	clientOutputStarted := false
-	codexFailureTerminal := account != nil && account.Platform == PlatformOpenAI
+	codexFailureTerminal := account != nil && account.IsOpenAIOAuthLike()
 	upstreamRequestID := strings.TrimSpace(resp.Header.Get("x-request-id"))
 	var streamEarlyErr error
 	terminalFailurePending := false
@@ -478,6 +478,18 @@ func (s *OpenAIGatewayService) handleStreamingResponseWithReasoning(ctx context.
 		if data, ok := extractOpenAISSEDataLine(line); ok {
 			dataBytes := []byte(data)
 			eventType := effectiveOpenAISSEEventType(dataBytes, pendingSSEEventType)
+			if codexFailureTerminal && sawBareError && !sawResponseFailed &&
+				(eventType == "response.completed" || eventType == "response.done") {
+				// A later successful terminal is authoritative over a pending bare
+				// error. Keep its usage and terminal visible to the client.
+				sawBareError = false
+				sawFailedEvent = false
+				terminalFailurePending = false
+				suppressCurrentEvent = false
+				bareErrorPayload = nil
+				bareErrorAccountSideEffectsPending = false
+				failedMessage = ""
+			}
 			if codexFailureTerminal && sawBareError && !sawResponseFailed && eventType != "response.failed" {
 				suppressCurrentEvent = true
 			}
@@ -862,10 +874,6 @@ func (s *OpenAIGatewayService) handleStreamingResponseWithReasoning(ctx context.
 			}
 
 		case <-intervalCh:
-			if codexFailureTerminal && sawBareError && !sawResponseFailed {
-				_ = resp.Body.Close()
-				return finalizeStream()
-			}
 			if failureDelivered {
 				return resultWithUsage(), fmt.Errorf("upstream response failed: %s", failedMessage)
 			}
@@ -873,6 +881,10 @@ func (s *OpenAIGatewayService) handleStreamingResponseWithReasoning(ctx context.
 			if time.Since(lastRead) < streamInterval {
 				continue
 			}
+			if codexFailureTerminal && sawBareError && !sawResponseFailed {
+				_ = resp.Body.Close()
+				return finalizeStream()
+			}
 			if clientDisconnected {
 				return resultWithUsage(), fmt.Errorf("stream usage incomplete after timeout")
 			}
@@ -899,7 +911,7 @@ func (s *OpenAIGatewayService) handleStreamingResponseWithReasoning(ctx context.
 				stopFirstOutputTimer()
 				continue
 			}
-			if codexFailureTerminal && sawBareError && !sawResponseFailed {
+			if codexFailureTerminal && sawBareError && !sawResponseFailed && len(events) == 0 {
 				_ = resp.Body.Close()
 				return finalizeStream()
 			}
@@ -1181,6 +1193,12 @@ func (s *OpenAIGatewayService) parseSSEUsageBytesWithType(data []byte, eventType
 	if usage == nil || len(data) == 0 || bytes.Equal(bytes.TrimSpace(data), []byte("[DONE]")) {
 		return
 	}
+	// Usage is absent from nearly every delta event. Avoid full JSON validation
+	// and four gjson path scans on that hot path while retaining progressive
+	// usage from compatible upstreams on any event type.
+	if !bytes.Contains(data, []byte(`"usage"`)) {
+		return
+	}
 	parsedUsage, ok := extractOpenAIUsageFromJSONBytes(data)
 	if !ok {
 		return
@@ -1368,6 +1386,57 @@ func extractOpenAIResponseIDFromJSONBytes(body []byte) string {
 	return strings.TrimSpace(gjson.GetBytes(body, "response.id").String())
 }
 
+const openAIHTTPResponseOwnerContextKey = "openai_http_response_owner"
+
+type openAIHTTPResponseOwner struct {
+	userID   int64
+	apiKeyID int64
+}
+
+// SetOpenAIHTTPResponseOwner marks the authenticated downstream owner whose
+// successful Responses IDs may be used for later HTTP continuations.
+func SetOpenAIHTTPResponseOwner(c *gin.Context, userID, apiKeyID int64) {
+	if c == nil || userID <= 0 || apiKeyID <= 0 {
+		return
+	}
+	c.Set(openAIHTTPResponseOwnerContextKey, openAIHTTPResponseOwner{userID: userID, apiKeyID: apiKeyID})
+}
+
+// ValidateOpenAIHTTPResponseOwner authorizes a continuation by downstream
+// tenant. API key identity is retained in the binding, while keys owned by the
+// same user remain interoperable.
+func (s *OpenAIGatewayService) ValidateOpenAIHTTPResponseOwner(
+	ctx context.Context,
+	groupID int64,
+	responseID string,
+	userID, apiKeyID int64,
+) (bool, error) {
+	if s == nil || strings.TrimSpace(responseID) == "" || userID <= 0 || apiKeyID <= 0 {
+		return false, nil
+	}
+	ownerUserID, ownerAPIKeyID, found, err := s.getOpenAIWSStateStore().GetHTTPResponseOwner(ctx, groupID, responseID)
+	if err != nil || !found {
+		return false, err
+	}
+	return ownerUserID == userID || (ownerUserID <= 0 && ownerAPIKeyID == apiKeyID), nil
+}
+
+// BindOpenAIHTTPResponseOwner records an HTTP continuation owner independently
+// from the upstream account selected for that response.
+func (s *OpenAIGatewayService) BindOpenAIHTTPResponseOwner(
+	ctx context.Context,
+	groupID int64,
+	responseID string,
+	userID, apiKeyID int64,
+) error {
+	if s == nil {
+		return nil
+	}
+	return s.getOpenAIWSStateStore().BindHTTPResponseOwner(
+		ctx, groupID, responseID, userID, apiKeyID, s.openAIWSResponseStickyTTL(),
+	)
+}
+
 func (s *OpenAIGatewayService) bindHTTPResponseAccount(ctx context.Context, c *gin.Context, account *Account, responseID string) {
 	if s == nil || account == nil || account.ID <= 0 {
 		return
@@ -1383,6 +1452,21 @@ func (s *OpenAIGatewayService) bindHTTPResponseAccount(ctx context.Context, c *g
 	groupID := getOpenAIGroupIDFromContext(c)
 	ttl := s.openAIWSResponseStickyTTL()
 	logOpenAIWSBindResponseAccountWarn(groupID, account.ID, responseID, store.BindResponseAccount(ctx, groupID, responseID, account.ID, ttl))
+	if rawOwner, ok := c.Get(openAIHTTPResponseOwnerContextKey); ok {
+		if owner, ok := rawOwner.(openAIHTTPResponseOwner); ok && owner.userID > 0 && owner.apiKeyID > 0 {
+			if err := s.BindOpenAIHTTPResponseOwner(ctx, groupID, responseID, owner.userID, owner.apiKeyID); err != nil {
+				logger.L().Warn(
+					"openai.http_bind_response_owner_failed",
+					zap.Int64("group_id", groupID),
+					zap.Int64("account_id", account.ID),
+					zap.Int64("user_id", owner.userID),
+					zap.Int64("api_key_id", owner.apiKeyID),
+					zap.String("response_id", truncateOpenAIWSLogValue(responseID, openAIWSIDValueMaxLen)),
+					zap.Error(err),
+				)
+			}
+		}
+	}
 }
 
 func openAIUsageFromGJSON(value gjson.Result) (OpenAIUsage, bool) {
@@ -1665,9 +1749,6 @@ func extractOpenAISSETerminalEvent(body string) (string, []byte, bool) {
 	var terminalType string
 	var terminalPayload []byte
 	forEachOpenAISSEFrame(body, func(eventType string, data []byte) {
-		if terminalPayload != nil {
-			return
-		}
 		switch eventType {
 		case "response.completed", "response.done", "response.failed", "response.incomplete", "response.cancelled", "response.canceled", "error":
 			terminalType = eventType
diff --git a/backend/internal/service/openai_gateway_service_test.go b/backend/internal/service/openai_gateway_service_test.go
index 122a542964..1e41298cc1 100644
--- a/backend/internal/service/openai_gateway_service_test.go
+++ b/backend/internal/service/openai_gateway_service_test.go
@@ -536,6 +536,7 @@ func TestOpenAIGatewayService_BindHTTPResponseAccount(t *testing.T) {
 	c.Request = httptest.NewRequest(http.MethodPost, "/openai/v1/responses", nil)
 	groupID := int64(4201)
 	c.Set("api_key", &APIKey{ID: 501, GroupID: &groupID})
+	SetOpenAIHTTPResponseOwner(c, 601, 501)
 
 	svc := &OpenAIGatewayService{}
 	account := &Account{ID: 37001, Platform: PlatformOpenAI, Type: AccountTypeAPIKey}
@@ -544,6 +545,22 @@ func TestOpenAIGatewayService_BindHTTPResponseAccount(t *testing.T) {
 	got, err := svc.getOpenAIWSStateStore().GetResponseAccount(context.Background(), groupID, "resp_http_001")
 	require.NoError(t, err)
 	require.Equal(t, account.ID, got)
+
+	owned, err := svc.ValidateOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_http_001", 601, 501)
+	require.NoError(t, err)
+	require.True(t, owned)
+
+	owned, err = svc.ValidateOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_http_001", 601, 502)
+	require.NoError(t, err)
+	require.True(t, owned, "API keys owned by the same downstream user remain interoperable")
+
+	owned, err = svc.ValidateOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_http_001", 602, 501)
+	require.NoError(t, err)
+	require.False(t, owned)
+
+	owned, err = svc.ValidateOpenAIHTTPResponseOwner(context.Background(), groupID, "resp_unknown", 601, 501)
+	require.NoError(t, err)
+	require.False(t, owned)
 }
 
 func TestOpenAIGatewayService_GenerateExplicitSessionHash_SkipsContentFallback(t *testing.T) {
diff --git a/backend/internal/service/openai_gateway_upstream_errors.go b/backend/internal/service/openai_gateway_upstream_errors.go
index 62add58e24..4a4e9ab7fc 100644
--- a/backend/internal/service/openai_gateway_upstream_errors.go
+++ b/backend/internal/service/openai_gateway_upstream_errors.go
@@ -260,7 +260,7 @@ func (s *OpenAIGatewayService) shouldFailoverOpenAIUpstreamResponse(statusCode i
 	if isOpenAIContextWindowError(upstreamMsg, upstreamBody) {
 		return false
 	}
-	if isOpenAIUpstreamAccessStateError(upstreamMsg, upstreamBody) {
+	if isOpenAIHTTPUpstreamAccessStateError(statusCode, upstreamMsg, upstreamBody) {
 		return true
 	}
 	if isOpenAIRequestBodyTooLargeError(statusCode, upstreamMsg, upstreamBody) {
@@ -306,7 +306,7 @@ func newOpenAIUpstreamFailoverError(
 		failoverErr.ClientStatusCode = http.StatusRequestEntityTooLarge
 		failoverErr.ClientMessage = OpenAIRequestBodyTooLargeClientMessage
 	}
-	if isOpenAIUpstreamAccessStateError(upstreamMsg, responseBody) {
+	if isOpenAIHTTPUpstreamAccessStateError(statusCode, upstreamMsg, responseBody) {
 		failoverErr.RetryableOnSameAccount = false
 		failoverErr.RequestScopedTransient = false
 		failoverErr.Stage = GatewayFailureStageAccountAuth
@@ -359,59 +359,42 @@ const (
 )
 
 // isOpenAIUpstreamAccessStateError recognizes provider-side credential state
-// failures from explicit structured fields. Valid JSON is never scanned as a
-// blob because it may contain echoed user input with the same words.
-func isOpenAIUpstreamAccessStateError(upstreamMsg string, body []byte) bool {
-	matchCode := func(value string) bool {
-		value = strings.ToLower(strings.TrimSpace(value))
-		if value == "deactivated_workspace" {
-			return true
-		}
-		for _, subject := range []string{"workspace", "account", "organization", "org"} {
-			for _, state := range []string{"deactivated", "disabled", "suspended"} {
-				if value == subject+"_"+state || value == state+"_"+subject {
-					return true
-				}
-			}
-		}
+// failures only from explicit structured codes. Free-form messages may contain
+// echoed user input, including inside stream terminal error.message fields.
+func isOpenAIUpstreamAccessStateError(_ string, body []byte) bool {
+	if len(body) == 0 || !gjson.ValidBytes(body) {
 		return false
 	}
-	matchMessage := func(value string) bool {
-		value = strings.ToLower(strings.TrimSpace(value))
-		for _, subject := range []string{"workspace", "account", "organization", "org"} {
-			for _, state := range []string{"deactivated", "disabled", "suspended"} {
-				if strings.Contains(value, subject+" is "+state) ||
-					strings.Contains(value, subject+" has been "+state) ||
-					strings.Contains(value, subject+" "+state) {
-					return true
-				}
-			}
-		}
-		return false
-	}
-
-	if matchMessage(upstreamMsg) {
-		return true
-	}
-	if len(body) == 0 {
-		return false
-	}
-	if !gjson.ValidBytes(body) {
-		return matchMessage(string(body)) || matchCode(string(body))
-	}
 	for _, path := range []string{"error.code", "response.error.code", "detail.code", "code"} {
-		if matchCode(gjson.GetBytes(body, path).String()) {
-			return true
-		}
-	}
-	for _, path := range []string{"error.message", "response.error.message", "detail.message", "detail", "message"} {
-		if matchMessage(gjson.GetBytes(body, path).String()) {
+		if isOpenAIUpstreamAccessStateCode(gjson.GetBytes(body, path).String()) {
 			return true
 		}
 	}
 	return false
 }
 
+func isOpenAIUpstreamAccessStateCode(value string) bool {
+	value = strings.ToLower(strings.TrimSpace(value))
+	if value == "deactivated_workspace" {
+		return true
+	}
+	for _, subject := range []string{"workspace", "account", "organization", "org"} {
+		for _, state := range []string{"deactivated", "disabled", "suspended"} {
+			if value == subject+"_"+state || value == state+"_"+subject {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// isOpenAIHTTPUpstreamAccessStateError is deliberately status-independent:
+// known provider codes are durable evidence, while 401/403 messages without
+// such a code must flow through the existing authentication/403 policies.
+func isOpenAIHTTPUpstreamAccessStateError(_ int, _ string, body []byte) bool {
+	return isOpenAIUpstreamAccessStateError("", body)
+}
+
 func openAICapacityShedClientMessage(upstreamMsg string, body []byte) string {
 	for _, candidate := range []string{
 		upstreamMsg,
diff --git a/backend/internal/service/openai_images.go b/backend/internal/service/openai_images.go
index c29af50016..08f94fca67 100644
--- a/backend/internal/service/openai_images.go
+++ b/backend/internal/service/openai_images.go
@@ -663,7 +663,7 @@ func (s *OpenAIGatewayService) forwardOpenAIImagesAPIKey(
 			if account.IsOpenAIOAuthLike() && resp.StatusCode == http.StatusTooManyRequests {
 				return nil, s.newOpenAIAccountFailoverError(account, resp.StatusCode, resp.Header, respBody, upstreamMsg, shouldDisable, retryableOnSameAccount)
 			}
-			if isOpenAIUpstreamAccessStateError(upstreamMsg, respBody) {
+			if isOpenAIHTTPUpstreamAccessStateError(resp.StatusCode, upstreamMsg, respBody) {
 				return nil, newOpenAIUpstreamFailoverError(resp.StatusCode, resp.Header, respBody, upstreamMsg, retryableOnSameAccount)
 			}
 			return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode, ResponseBody: respBody, RetryableOnSameAccount: retryableOnSameAccount}
diff --git a/backend/internal/service/openai_response_terminal_usage_compat_test.go b/backend/internal/service/openai_response_terminal_usage_compat_test.go
index f6dc899e09..5a24f0addb 100644
--- a/backend/internal/service/openai_response_terminal_usage_compat_test.go
+++ b/backend/internal/service/openai_response_terminal_usage_compat_test.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/Wei-Shaw/sub2api/internal/pkg/apicompat"
 	"github.com/stretchr/testify/require"
+	"github.com/tidwall/gjson"
 )
 
 func TestEffectiveOpenAISSEEventTypePrefersPayload(t *testing.T) {
@@ -31,6 +32,17 @@ func TestExtractOpenAISSETerminalEventUsesEventField(t *testing.T) {
 	require.Equal(t, "provider failed", extractOpenAISSEErrorMessage(payload))
 }
 
+func TestExtractOpenAISSETerminalEventUsesFinalAuthoritativeTerminal(t *testing.T) {
+	t.Parallel()
+
+	body := "data: {\"type\":\"error\",\"error\":{\"message\":\"recovering\"}}\n\n" +
+		"data: {\"type\":\"response.completed\",\"response\":{\"id\":\"resp_1\",\"status\":\"completed\"}}\n\n"
+	eventType, payload, ok := extractOpenAISSETerminalEvent(body)
+	require.True(t, ok)
+	require.Equal(t, "response.completed", eventType)
+	require.Equal(t, "resp_1", gjson.GetBytes(payload, "response.id").String())
+}
+
 func TestParseSSEUsageEffectiveTerminalRules(t *testing.T) {
 	t.Parallel()
 
@@ -47,6 +59,17 @@ func TestParseSSEUsageEffectiveTerminalRules(t *testing.T) {
 	require.Equal(t, OpenAIUsage{InputTokens: 2}, *usage)
 }
 
+func BenchmarkParseSSEUsageNoUsageDelta(b *testing.B) {
+	svc := &OpenAIGatewayService{}
+	usage := &OpenAIUsage{}
+	payload := []byte(`{"type":"response.output_text.delta","delta":"hello"}`)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		svc.parseSSEUsageBytesWithType(payload, "response.output_text.delta", usage)
+	}
+}
+
 func TestOpenAICompatTerminalResponseSynthesizesBareError(t *testing.T) {
 	t.Parallel()
 
diff --git a/backend/internal/service/openai_responses_ingress_compat.go b/backend/internal/service/openai_responses_ingress_compat.go
index c9ae11c0ae..f3162b3b02 100644
--- a/backend/internal/service/openai_responses_ingress_compat.go
+++ b/backend/internal/service/openai_responses_ingress_compat.go
@@ -46,11 +46,17 @@ func normalizeOpenAIResponsesLegacyIngress(body []byte) ([]byte, bool, error) {
 	}
 
 	if prompt, hasPrompt := request["prompt"]; hasPrompt {
-		if input, hasInput := request["input"]; (!hasInput || input == nil) && prompt != nil {
-			request["input"] = prompt
+		// Only the legacy string alias is unambiguously equivalent to Responses
+		// input. Objects are native reusable prompt templates and must remain in
+		// prompt; arrays and other shapes are left for upstream validation rather
+		// than being relabeled as a structurally different input value.
+		if promptText, isLegacyString := prompt.(string); isLegacyString {
+			if input, hasInput := request["input"]; !hasInput || input == nil {
+				request["input"] = promptText
+			}
+			delete(request, "prompt")
+			changed = true
 		}
-		delete(request, "prompt")
-		changed = true
 	}
 	if _, hasCommands := request["commands"]; hasCommands {
 		delete(request, "commands")
diff --git a/backend/internal/service/openai_responses_ingress_compat_test.go b/backend/internal/service/openai_responses_ingress_compat_test.go
index 3e898f03e6..acd2c202c0 100644
--- a/backend/internal/service/openai_responses_ingress_compat_test.go
+++ b/backend/internal/service/openai_responses_ingress_compat_test.go
@@ -70,3 +70,25 @@ func TestNormalizeOpenAIResponsesLegacyIngressKeepsPromptAliasAndDropsCommands(t
 	require.False(t, gjson.GetBytes(normalized, "prompt").Exists())
 	require.False(t, gjson.GetBytes(normalized, "commands").Exists())
 }
+
+func TestNormalizeOpenAIResponsesLegacyIngressPreservesNativePromptTemplate(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","prompt":{"id":"pmpt_abc","version":"7","variables":{"topic":"ownership"}}}`)
+
+	normalized, changed, err := normalizeOpenAIResponsesLegacyIngress(body)
+	require.NoError(t, err)
+	require.False(t, changed)
+	require.JSONEq(t, string(body), string(normalized))
+	require.Equal(t, "pmpt_abc", gjson.GetBytes(normalized, "prompt.id").String())
+	require.False(t, gjson.GetBytes(normalized, "input").Exists())
+}
+
+func TestNormalizeOpenAIResponsesLegacyIngressPreservesUnknownPromptShapeWhileDroppingCommands(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","prompt":["one","two"],"commands":[{"name":"legacy"}]}`)
+
+	normalized, changed, err := normalizeOpenAIResponsesLegacyIngress(body)
+	require.NoError(t, err)
+	require.True(t, changed)
+	require.Equal(t, int64(2), gjson.GetBytes(normalized, "prompt.#").Int())
+	require.False(t, gjson.GetBytes(normalized, "input").Exists())
+	require.False(t, gjson.GetBytes(normalized, "commands").Exists())
+}
diff --git a/backend/internal/service/openai_responses_item_id.go b/backend/internal/service/openai_responses_item_id.go
index f4621aa395..3a10966e89 100644
--- a/backend/internal/service/openai_responses_item_id.go
+++ b/backend/internal/service/openai_responses_item_id.go
@@ -70,35 +70,20 @@ func sanitizeOpenAIResponsesInputItemIDs(body []byte) ([]byte, bool, error) {
 
 	type inputItem struct {
 		body        []byte
-		itemType    string
-		id          string
-		callID      string
 		stripID     bool
 		stripCallID bool
-		drop        bool
-		isObject    bool
 	}
 
 	items := make([]inputItem, 0)
-	strippedIDs := make(map[string]struct{})
-	validCallIDs := make(map[string]struct{})
 	input.ForEach(func(_, item gjson.Result) bool {
-		parsed := inputItem{body: []byte(item.Raw), isObject: item.IsObject()}
+		parsed := inputItem{body: []byte(item.Raw)}
 		if item.IsObject() {
 			itemType := item.Get("type")
 			id := item.Get("id")
-			parsed.itemType = strings.TrimSpace(itemType.String())
-			parsed.callID = strings.TrimSpace(item.Get("call_id").String())
-			parsed.stripCallID = item.Get("call_id").Exists() && shouldStripOpenAIResponsesNonPairCallID(parsed.itemType)
+			trimmedItemType := strings.TrimSpace(itemType.String())
+			parsed.stripCallID = item.Get("call_id").Exists() && shouldStripOpenAIResponsesNonPairCallID(trimmedItemType)
 			if id.Type == gjson.String {
-				parsed.id = id.String()
-				parsed.stripID = shouldStripOpenAIResponsesInputItemID(parsed.itemType, parsed.id)
-				if parsed.stripID && parsed.id != "" {
-					strippedIDs[parsed.id] = struct{}{}
-				}
-			}
-			if isCodexToolCallContextItemType(parsed.itemType) && parsed.callID != "" {
-				validCallIDs[parsed.callID] = struct{}{}
+				parsed.stripID = shouldStripOpenAIResponsesInputItemID(trimmedItemType, id.String())
 			}
 		}
 		items = append(items, parsed)
@@ -115,51 +100,8 @@ func sanitizeOpenAIResponsesInputItemIDs(body []byte) ([]byte, bool, error) {
 		return body, false, nil
 	}
 
-	// First decide which outputs become dangling because their call_id points at
-	// an item ID that is being removed and no call item owns that call_id. This
-	// must happen before computing retained IDs: a dropped output cannot keep an
-	// item_reference alive merely because it used to have the same id.
-	for index := range items {
-		item := &items[index]
-		if !item.isObject || !isCodexToolCallOutputItemType(item.itemType) {
-			continue
-		}
-		if _, pointsAtStrippedID := strippedIDs[item.callID]; !pointsAtStrippedID {
-			continue
-		}
-		if _, hasMatchingCallID := validCallIDs[item.callID]; !hasMatchingCallID {
-			item.drop = true
-		}
-	}
-
-	removedItemIDs := make(map[string]struct{}, len(strippedIDs))
-	retainedItemIDs := make(map[string]struct{}, len(items))
-	for _, item := range items {
-		if item.id == "" || item.itemType == "item_reference" {
-			continue
-		}
-		if item.stripID || item.drop {
-			removedItemIDs[item.id] = struct{}{}
-			continue
-		}
-		retainedItemIDs[item.id] = struct{}{}
-	}
-	for id := range retainedItemIDs {
-		delete(removedItemIDs, id)
-	}
-
 	rebuiltItems := make([][]byte, 0, len(items))
 	for index, item := range items {
-		if item.isObject {
-			if item.itemType == "item_reference" {
-				if _, dangling := removedItemIDs[item.id]; dangling {
-					continue
-				}
-			}
-			if item.drop {
-				continue
-			}
-		}
 		itemBody := item.body
 		if item.stripID {
 			var err error
diff --git a/backend/internal/service/openai_responses_item_id_test.go b/backend/internal/service/openai_responses_item_id_test.go
index 17a0b2f9bc..b300b22a2e 100644
--- a/backend/internal/service/openai_responses_item_id_test.go
+++ b/backend/internal/service/openai_responses_item_id_test.go
@@ -45,11 +45,11 @@ func TestOpenAIResponsesInputItemIDPrefixUsesObservedOutputContracts(t *testing.
 	}
 }
 
-func TestSanitizeOpenAIResponsesInputItemIDsKeepsReferenceGraphConsistent(t *testing.T) {
+func TestSanitizeOpenAIResponsesInputItemIDsDoesNotCascadeAcrossIDNamespaces(t *testing.T) {
 	body := []byte(`{"input":[
 		{"type":"function_call","id":"item_bad_call","call_id":"call_valid","name":"lookup","arguments":"{}"},
 		{"type":"function_call_output","call_id":"call_valid","output":"preserve paired output"},
-		{"type":"function_call_output","call_id":"item_bad_call","output":"drop dangling output"},
+		{"type":"function_call_output","call_id":"item_bad_call","output":"preserve opaque output"},
 		{"type":"item_reference","id":"item_bad_call"},
 		{"type":"item_reference","id":"remote_valid"},
 		{"type":"custom_tool_call","id":"ctc_valid","call_id":"ctco_bad_output","name":"apply_patch","input":"patch"},
@@ -61,14 +61,16 @@ func TestSanitizeOpenAIResponsesInputItemIDsKeepsReferenceGraphConsistent(t *tes
 	require.NoError(t, err)
 	require.True(t, changed)
 	items := gjson.GetBytes(sanitized, "input").Array()
-	require.Len(t, items, 5)
+	require.Len(t, items, 7)
 	require.False(t, items[0].Get("id").Exists())
 	require.Equal(t, "call_valid", items[0].Get("call_id").String())
 	require.Equal(t, "preserve paired output", items[1].Get("output").String())
-	require.Equal(t, "remote_valid", items[2].Get("id").String())
-	require.Equal(t, "ctc_valid", items[3].Get("id").String())
-	require.False(t, items[4].Get("id").Exists())
-	require.Equal(t, "ctco_bad_output", items[4].Get("call_id").String())
+	require.Equal(t, "preserve opaque output", items[2].Get("output").String())
+	require.Equal(t, "item_bad_call", items[3].Get("id").String())
+	require.Equal(t, "remote_valid", items[4].Get("id").String())
+	require.Equal(t, "ctc_valid", items[5].Get("id").String())
+	require.False(t, items[6].Get("id").Exists())
+	require.Equal(t, "ctco_bad_output", items[6].Get("call_id").String())
 }
 
 func TestSanitizeOpenAIResponsesInputItemIDsLeavesUnrelatedReferencesUntouched(t *testing.T) {
@@ -93,7 +95,7 @@ func TestSanitizeOpenAIResponsesInputItemIDsPreservesReferenceToDuplicateRetaine
 	require.Equal(t, "ctc_shared", gjson.GetBytes(sanitized, "input.2.id").String())
 }
 
-func TestSanitizeOpenAIResponsesInputItemIDsClosesReferencesAfterDroppingOutput(t *testing.T) {
+func TestSanitizeOpenAIResponsesInputItemIDsPreservesOpaqueOutputsAndReferences(t *testing.T) {
 	body := []byte(`{"input":[
 		{"type":"function_call","id":"item_shared","call_id":"call_real"},
 		{"type":"function_call_output","id":"item_shared","call_id":"item_shared","output":"dangling"},
@@ -106,10 +108,12 @@ func TestSanitizeOpenAIResponsesInputItemIDsClosesReferencesAfterDroppingOutput(
 
 	require.NoError(t, err)
 	require.True(t, changed)
-	require.Len(t, gjson.GetBytes(sanitized, "input").Array(), 3)
+	require.Len(t, gjson.GetBytes(sanitized, "input").Array(), 5)
 	require.False(t, gjson.GetBytes(sanitized, "input.0.id").Exists())
-	require.Equal(t, "kept_output", gjson.GetBytes(sanitized, "input.1.id").String())
-	require.Equal(t, "kept_output", gjson.GetBytes(sanitized, "input.2.id").String())
+	require.Equal(t, "dangling", gjson.GetBytes(sanitized, "input.1.output").String())
+	require.Equal(t, "item_shared", gjson.GetBytes(sanitized, "input.2.id").String())
+	require.Equal(t, "kept_output", gjson.GetBytes(sanitized, "input.3.id").String())
+	require.Equal(t, "kept_output", gjson.GetBytes(sanitized, "input.4.id").String())
 
 	second, changedAgain, err := sanitizeOpenAIResponsesInputItemIDs(sanitized)
 	require.NoError(t, err)
diff --git a/backend/internal/service/openai_responses_tool_schema.go b/backend/internal/service/openai_responses_tool_schema.go
index 08c9ecc2d6..c77640d0e3 100644
--- a/backend/internal/service/openai_responses_tool_schema.go
+++ b/backend/internal/service/openai_responses_tool_schema.go
@@ -26,13 +26,45 @@ const (
 
 var errOpenAIResponsesToolSchemaLimit = errors.New("OpenAI Responses tool schema safety limit exceeded")
 
-// shouldSanitizeOpenAIResponsesToolSchemas centralizes the platform boundary
-// for callers. These rewrites describe OpenAI Responses constraints, not the
-// behavior of every provider routed through the generic OpenAI gateway.
-func shouldSanitizeOpenAIResponsesToolSchemas(platform string) bool {
+// shouldRepairOpenAIResponsesNullToolSchemaType reports whether the upstream
+// path requires a concrete object type at a function tool's parameter root.
+// This defect is shared by the OpenAI, Anthropic, and CN-compatible paths.
+func shouldRepairOpenAIResponsesNullToolSchemaType(platform string) bool {
+	return platform == PlatformOpenAI || platform == PlatformAnthropic || IsCNProvider(platform)
+}
+
+// shouldSanitizeOpenAIResponsesToolSchemaPatterns is intentionally narrower:
+// regex lookaround rejection is an OpenAI-specific schema constraint.
+func shouldSanitizeOpenAIResponsesToolSchemaPatterns(platform string) bool {
 	return platform == PlatformOpenAI
 }
 
+func sanitizeOpenAIResponsesToolSchemasForPlatform(body []byte, platform string) ([]byte, bool, error) {
+	normalized := body
+	changed := false
+	if shouldRepairOpenAIResponsesNullToolSchemaType(platform) {
+		next, repaired, err := sanitizeOpenAIResponsesToolParameterTypes(normalized)
+		if err != nil {
+			return body, false, fmt.Errorf("sanitize OpenAI Responses tool parameters: %w", err)
+		}
+		if repaired {
+			normalized = next
+			changed = true
+		}
+	}
+	if shouldSanitizeOpenAIResponsesToolSchemaPatterns(platform) {
+		next, sanitized, err := sanitizeOpenAIResponsesToolSchemaPatterns(normalized)
+		if err != nil {
+			return body, false, fmt.Errorf("sanitize OpenAI Responses tool schema patterns: %w", err)
+		}
+		if sanitized {
+			normalized = next
+			changed = true
+		}
+	}
+	return normalized, changed, nil
+}
+
 // sanitizeOpenAIResponsesToolSchemaPatterns removes only schema constraints
 // containing regex lookaround, which OpenAI rejects. It deliberately does not
 // descend into instance-valued keywords such as default, examples, const, or
diff --git a/backend/internal/service/openai_responses_tool_schema_test.go b/backend/internal/service/openai_responses_tool_schema_test.go
index eeb9cf5dab..cf676645e1 100644
--- a/backend/internal/service/openai_responses_tool_schema_test.go
+++ b/backend/internal/service/openai_responses_tool_schema_test.go
@@ -239,11 +239,59 @@ func TestSanitizeOpenAIResponsesToolSchemas_InvalidAndTrailingJSON(t *testing.T)
 	}
 }
 
-func TestShouldSanitizeOpenAIResponsesToolSchemas_PlatformBoundary(t *testing.T) {
-	require.True(t, shouldSanitizeOpenAIResponsesToolSchemas(PlatformOpenAI))
-	for _, platform := range []string{PlatformGrok, PlatformKimi, PlatformZhipu, PlatformDeepseek, PlatformComposite, ""} {
-		require.False(t, shouldSanitizeOpenAIResponsesToolSchemas(platform), platform)
+func TestOpenAIResponsesToolSchemaCapabilities_PlatformBoundary(t *testing.T) {
+	tests := []struct {
+		platform         string
+		repairNullType   bool
+		removeLookaround bool
+	}{
+		{PlatformOpenAI, true, true},
+		{PlatformAnthropic, true, false},
+		{PlatformKimi, true, false},
+		{PlatformZhipu, true, false},
+		{PlatformDeepseek, true, false},
+		{PlatformGrok, false, false},
+		{PlatformGemini, false, false},
+		{PlatformAntigravity, false, false},
+		{PlatformComposite, false, false},
+		{"", false, false},
 	}
+	for _, tt := range tests {
+		t.Run(tt.platform, func(t *testing.T) {
+			require.Equal(t, tt.repairNullType, shouldRepairOpenAIResponsesNullToolSchemaType(tt.platform))
+			require.Equal(t, tt.removeLookaround, shouldSanitizeOpenAIResponsesToolSchemaPatterns(tt.platform))
+		})
+	}
+}
+
+func TestSanitizeOpenAIResponsesToolSchemasForPlatform_ReplayBoundary(t *testing.T) {
+	body := []byte(`{"tools":[{"type":"function","parameters":{"type":null,"properties":{"query":{"type":"string","pattern":"(?=keep)"}}}}]}`)
+
+	// A malformed tool definition may be replayed after account failover. Every
+	// compatible account must repair it, while non-OpenAI providers retain their
+	// supported regex semantics.
+	for _, platform := range []string{PlatformAnthropic, PlatformKimi, PlatformZhipu, PlatformDeepseek} {
+		t.Run(platform, func(t *testing.T) {
+			for attempt := 0; attempt < 2; attempt++ {
+				normalized, changed, err := sanitizeOpenAIResponsesToolSchemasForPlatform(body, platform)
+				require.NoError(t, err)
+				require.True(t, changed)
+				require.Equal(t, "object", gjson.GetBytes(normalized, "tools.0.parameters.type").String())
+				require.Equal(t, "(?=keep)", gjson.GetBytes(normalized, "tools.0.parameters.properties.query.pattern").String())
+			}
+		})
+	}
+
+	openAI, changed, err := sanitizeOpenAIResponsesToolSchemasForPlatform(body, PlatformOpenAI)
+	require.NoError(t, err)
+	require.True(t, changed)
+	require.Equal(t, "object", gjson.GetBytes(openAI, "tools.0.parameters.type").String())
+	require.False(t, gjson.GetBytes(openAI, "tools.0.parameters.properties.query.pattern").Exists())
+
+	unsupported, changed, err := sanitizeOpenAIResponsesToolSchemasForPlatform(body, PlatformGrok)
+	require.NoError(t, err)
+	require.False(t, changed)
+	require.Equal(t, string(body), string(unsupported))
 }
 
 // 索引映射：只有坏条目被改，前后兄弟条目按原下标保持不变。
diff --git a/backend/internal/service/openai_upstream_client_error_test.go b/backend/internal/service/openai_upstream_client_error_test.go
index 2b6ed51967..291c1c491e 100644
--- a/backend/internal/service/openai_upstream_client_error_test.go
+++ b/backend/internal/service/openai_upstream_client_error_test.go
@@ -164,6 +164,7 @@ func TestHandleErrorResponse_NonDeterministicStatusesKeepGeneric502(t *testing.T
 		{"unprocessable", http.StatusUnprocessableEntity, `{"error":{"message":"Invalid schema for field messages"}}`,
 			http.StatusBadGateway, "upstream_error", "Upstream request failed"},
 		// 401/402/403 是网关运营方的凭据/账单问题，必须继续对客户端屏蔽上游账号状态。
+		// 403 的自由文本不能升级成 durable access-state typed failover；只有明确结构化 code 才可以。
 		{"unauthorized", http.StatusUnauthorized, `{"error":{"message":"Incorrect API key provided: sk-abc"}}`,
 			http.StatusBadGateway, "upstream_error", "Upstream authentication failed, please contact administrator"},
 		{"forbidden", http.StatusForbidden, `{"error":{"message":"Your account is deactivated"}}`,
@@ -183,15 +184,11 @@ func TestHandleErrorResponse_NonDeterministicStatusesKeepGeneric502(t *testing.T
 				newOpenAIUpstreamErrorResponse(tc.statusCode, tc.body),
 				c, newOpenAIUpstreamErrorTestAccount(), nil,
 			)
+			require.Error(t, err)
 			if tc.name == "forbidden" {
 				var failoverErr *UpstreamFailoverError
-				require.ErrorAs(t, err, &failoverErr)
-				require.Equal(t, http.StatusForbidden, failoverErr.StatusCode)
-				require.False(t, c.Writer.Written())
-				return
+				require.False(t, errors.As(err, &failoverErr))
 			}
-
-			require.Error(t, err)
 			require.Equal(t, tc.wantStatus, rec.Code)
 			require.Equal(t, tc.wantType, gjson.Get(rec.Body.String(), "error.type").String())
 			require.Equal(t, tc.wantMsg, gjson.Get(rec.Body.String(), "error.message").String())
diff --git a/backend/internal/service/openai_ws_http_bridge.go b/backend/internal/service/openai_ws_http_bridge.go
index ae41c3bbbd..3f5d1e57b5 100644
--- a/backend/internal/service/openai_ws_http_bridge.go
+++ b/backend/internal/service/openai_ws_http_bridge.go
@@ -489,6 +489,7 @@ func (s *OpenAIGatewayService) proxyOpenAIWSHTTPBridgeTurn(
 	pendingClientMessageBytes := int64(0)
 	capacityFailoverSuppressedLogged := false
 	clientDisconnected := false
+	officialOpenAIResponses := account != nil && account.Platform == PlatformOpenAI
 	bareErrorPending := false
 	var bareErrorPayload []byte
 	bareErrorMessage := ""
@@ -642,7 +643,15 @@ func (s *OpenAIGatewayService) proxyOpenAIWSHTTPBridgeTurn(
 		replayCollector.AddEvent(eventType, upstreamMessage)
 
 		var upstreamEventErr error
-		suppressClientMessage := bareErrorPending && eventType != "response.failed"
+		if officialOpenAIResponses && bareErrorPending && (eventType == "response.completed" || eventType == "response.done") {
+			// Some upstreams emit a recoverable bare error before the authoritative
+			// successful terminal. Do not replace that terminal with a synthetic
+			// failure or retain side effects from the superseded error.
+			bareErrorPending = false
+			bareErrorPayload = nil
+			bareErrorMessage = ""
+		}
+		suppressClientMessage := officialOpenAIResponses && bareErrorPending && eventType != "response.failed"
 		if eventType == "error" || eventType == "response.failed" {
 			errMessage := extractOpenAISSEErrorMessage(upstreamMessage)
 			if errMessage == "" {
@@ -677,7 +686,7 @@ func (s *OpenAIGatewayService) proxyOpenAIWSHTTPBridgeTurn(
 				return nil, s.newOpenAIStreamFailoverError(c, account, true, resp.Header.Get("x-request-id"), upstreamMessage, errMessage, resp.Header)
 			}
 			if account.Platform != PlatformGrok && !failureAccountSideEffectsApplied {
-				if eventType == "response.failed" || (shouldFailover && !requestScopedCapacity) {
+				if eventType == "response.failed" || (!officialOpenAIResponses && shouldFailover && !requestScopedCapacity) {
 					failureAccountSideEffectsApplied = s.handleOpenAIWSFailureAccountSideEffects(ctx, account, mappedModel, resp.Header, upstreamMessage)
 				}
 			}
@@ -685,7 +694,7 @@ func (s *OpenAIGatewayService) proxyOpenAIWSHTTPBridgeTurn(
 				logOpenAICapacityFailoverSuppressed(ctx, account, "ws_http_bridge", resp.Header.Get("x-request-id"), eventType)
 				capacityFailoverSuppressedLogged = true
 			}
-			if eventType == "error" && account.Platform == PlatformGrok {
+			if eventType == "error" && !officialOpenAIResponses {
 				upstreamEventErr = errors.New(errMessage)
 			} else if eventType == "error" {
 				bareErrorPending = true
diff --git a/backend/internal/service/openai_ws_http_bridge_test.go b/backend/internal/service/openai_ws_http_bridge_test.go
index a8c10cf893..4aec9d7d8a 100644
--- a/backend/internal/service/openai_ws_http_bridge_test.go
+++ b/backend/internal/service/openai_ws_http_bridge_test.go
@@ -758,6 +758,40 @@ func TestProxyOpenAIWSHTTPBridgeTurnBareErrorEOFSynthesizesFailed(t *testing.T)
 	require.Equal(t, "resp_eof", gjson.GetBytes(writes[1], "response.id").String())
 }
 
+func TestProxyOpenAIWSHTTPBridgeTurnBareErrorFollowedByCompletedUsesCompleted(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	body := strings.Join([]string{
+		`data: {"type":"response.created","response":{"id":"resp_recovered","status":"in_progress"}}`,
+		``,
+		`data: {"type":"error","error":{"code":"transient","message":"retrying"}}`,
+		``,
+		`data: {"type":"response.completed","response":{"id":"resp_recovered","status":"completed","output":[],"usage":{"input_tokens":8,"output_tokens":4}}}`,
+		``,
+	}, "\n")
+	upstream := &httpUpstreamRecorder{resp: &http.Response{StatusCode: http.StatusOK, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(body))}}
+	svc := &OpenAIGatewayService{cfg: &config.Config{}, httpUpstream: upstream}
+	account := &Account{ID: 113, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Concurrency: 1}
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodGet, "/v1/responses", nil)
+	payload := []byte(`{"type":"response.create","model":"gpt-5","input":"hi"}`)
+	var writes [][]byte
+
+	result, err := svc.proxyOpenAIWSHTTPBridgeTurn(context.Background(), c, account, "sk-test", payload, len(payload), "gpt-5", "", "", "", "", 2, func(message []byte) error {
+		writes = append(writes, append([]byte(nil), message...))
+		return nil
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, "response.completed", result.UpstreamTerminalEvent)
+	require.Equal(t, 8, result.Usage.InputTokens)
+	require.Equal(t, 4, result.Usage.OutputTokens)
+	require.Len(t, writes, 2)
+	require.Equal(t, "response.created", gjson.GetBytes(writes[0], "type").String())
+	require.Equal(t, "response.completed", gjson.GetBytes(writes[1], "type").String())
+}
+
 func TestProxyOpenAIWSHTTPBridgeTurnStagesMetadataBeforeCapacityFailover(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	body := strings.Join([]string{
diff --git a/backend/internal/service/openai_ws_state_store.go b/backend/internal/service/openai_ws_state_store.go
index d3b6891b0a..fe4ee54926 100644
--- a/backend/internal/service/openai_ws_state_store.go
+++ b/backend/internal/service/openai_ws_state_store.go
@@ -13,6 +13,8 @@ import (
 
 const (
 	openAIWSResponseAccountCachePrefix = "openai:response:"
+	openAIHTTPResponseOwnerUserPrefix  = "openai:http-response-owner:user:"
+	openAIHTTPResponseOwnerKeyPrefix   = "openai:http-response-owner:key:"
 	openAIWSStateStoreCleanupInterval  = time.Minute
 	openAIWSStateStoreCleanupMaxPerMap = 512
 	openAIWSStateStoreMaxEntriesPerMap = 65536
@@ -24,6 +26,12 @@ type openAIWSAccountBinding struct {
 	expiresAt time.Time
 }
 
+type openAIHTTPResponseOwnerBinding struct {
+	userID    int64
+	apiKeyID  int64
+	expiresAt time.Time
+}
+
 type openAIWSConnBinding struct {
 	connID    string
 	expiresAt time.Time
@@ -49,6 +57,8 @@ type OpenAIWSStateStore interface {
 	BindResponseAccount(ctx context.Context, groupID int64, responseID string, accountID int64, ttl time.Duration) error
 	GetResponseAccount(ctx context.Context, groupID int64, responseID string) (int64, error)
 	DeleteResponseAccount(ctx context.Context, groupID int64, responseID string) error
+	BindHTTPResponseOwner(ctx context.Context, groupID int64, responseID string, userID, apiKeyID int64, ttl time.Duration) error
+	GetHTTPResponseOwner(ctx context.Context, groupID int64, responseID string) (userID, apiKeyID int64, found bool, err error)
 
 	BindResponseConn(responseID, connID string, ttl time.Duration)
 	GetResponseConn(responseID string) (string, bool)
@@ -68,6 +78,8 @@ type defaultOpenAIWSStateStore struct {
 
 	responseToAccountMu  sync.RWMutex
 	responseToAccount    map[string]openAIWSAccountBinding
+	responseOwnerMu      sync.RWMutex
+	responseOwners       map[string]openAIHTTPResponseOwnerBinding
 	responseToConnMu     sync.RWMutex
 	responseToConn       map[string]openAIWSConnBinding
 	sessionToTurnStateMu sync.RWMutex
@@ -83,6 +95,7 @@ func NewOpenAIWSStateStore(cache GatewayCache) OpenAIWSStateStore {
 	store := &defaultOpenAIWSStateStore{
 		cache:              cache,
 		responseToAccount:  make(map[string]openAIWSAccountBinding, 256),
+		responseOwners:     make(map[string]openAIHTTPResponseOwnerBinding, 256),
 		responseToConn:     make(map[string]openAIWSConnBinding, 256),
 		sessionToTurnState: make(map[string]openAIWSTurnStateBinding, 256),
 		sessionToConn:      make(map[string]openAIWSSessionConnBinding, 256),
@@ -91,6 +104,72 @@ func NewOpenAIWSStateStore(cache GatewayCache) OpenAIWSStateStore {
 	return store
 }
 
+func (s *defaultOpenAIWSStateStore) BindHTTPResponseOwner(ctx context.Context, groupID int64, responseID string, userID, apiKeyID int64, ttl time.Duration) error {
+	id := normalizeOpenAIWSResponseID(responseID)
+	if id == "" || userID <= 0 || apiKeyID <= 0 {
+		return nil
+	}
+	ttl = normalizeOpenAIWSTTL(ttl)
+	s.maybeCleanup()
+
+	mapKey := openAIWSResponseAccountMapKey(groupID, id)
+	s.responseOwnerMu.Lock()
+	ensureBindingCapacity(s.responseOwners, mapKey, openAIWSStateStoreMaxEntriesPerMap)
+	s.responseOwners[mapKey] = openAIHTTPResponseOwnerBinding{
+		userID: userID, apiKeyID: apiKeyID, expiresAt: time.Now().Add(ttl),
+	}
+	s.responseOwnerMu.Unlock()
+
+	if s.cache == nil {
+		return nil
+	}
+	cacheCtx, cancel := withOpenAIWSStateStoreRedisTimeout(ctx)
+	defer cancel()
+	if err := s.cache.SetSessionAccountID(cacheCtx, groupID, openAIHTTPResponseOwnerCacheKey(openAIHTTPResponseOwnerUserPrefix, id), userID, ttl); err != nil {
+		return err
+	}
+	return s.cache.SetSessionAccountID(cacheCtx, groupID, openAIHTTPResponseOwnerCacheKey(openAIHTTPResponseOwnerKeyPrefix, id), apiKeyID, ttl)
+}
+
+func (s *defaultOpenAIWSStateStore) GetHTTPResponseOwner(ctx context.Context, groupID int64, responseID string) (int64, int64, bool, error) {
+	id := normalizeOpenAIWSResponseID(responseID)
+	if id == "" {
+		return 0, 0, false, nil
+	}
+	s.maybeCleanup()
+
+	now := time.Now()
+	mapKey := openAIWSResponseAccountMapKey(groupID, id)
+	s.responseOwnerMu.RLock()
+	if binding, ok := s.responseOwners[mapKey]; ok && now.Before(binding.expiresAt) {
+		s.responseOwnerMu.RUnlock()
+		return binding.userID, binding.apiKeyID, true, nil
+	}
+	s.responseOwnerMu.RUnlock()
+
+	if s.cache == nil {
+		return 0, 0, false, nil
+	}
+	cacheCtx, cancel := withOpenAIWSStateStoreRedisTimeout(ctx)
+	defer cancel()
+	userID, err := s.cache.GetSessionAccountID(cacheCtx, groupID, openAIHTTPResponseOwnerCacheKey(openAIHTTPResponseOwnerUserPrefix, id))
+	if err != nil || userID <= 0 {
+		return 0, 0, false, err
+	}
+	apiKeyID, err := s.cache.GetSessionAccountID(cacheCtx, groupID, openAIHTTPResponseOwnerCacheKey(openAIHTTPResponseOwnerKeyPrefix, id))
+	if err != nil || apiKeyID <= 0 {
+		return 0, 0, false, err
+	}
+
+	s.responseOwnerMu.Lock()
+	ensureBindingCapacity(s.responseOwners, mapKey, openAIWSStateStoreMaxEntriesPerMap)
+	s.responseOwners[mapKey] = openAIHTTPResponseOwnerBinding{
+		userID: userID, apiKeyID: apiKeyID, expiresAt: now.Add(time.Minute),
+	}
+	s.responseOwnerMu.Unlock()
+	return userID, apiKeyID, true, nil
+}
+
 func (s *defaultOpenAIWSStateStore) BindResponseAccount(ctx context.Context, groupID int64, responseID string, accountID int64, ttl time.Duration) error {
 	id := normalizeOpenAIWSResponseID(responseID)
 	if id == "" || accountID <= 0 {
@@ -115,6 +194,22 @@ func (s *defaultOpenAIWSStateStore) BindResponseAccount(ctx context.Context, gro
 	return s.cache.SetSessionAccountID(cacheCtx, groupID, cacheKey, accountID, ttl)
 }
 
+func cleanupExpiredHTTPResponseOwnerBindings(bindings map[string]openAIHTTPResponseOwnerBinding, now time.Time, maxScan int) {
+	if len(bindings) == 0 || maxScan <= 0 {
+		return
+	}
+	scanned := 0
+	for key, binding := range bindings {
+		if now.After(binding.expiresAt) {
+			delete(bindings, key)
+		}
+		scanned++
+		if scanned >= maxScan {
+			break
+		}
+	}
+}
+
 func (s *defaultOpenAIWSStateStore) GetResponseAccount(ctx context.Context, groupID int64, responseID string) (int64, error) {
 	id := normalizeOpenAIWSResponseID(responseID)
 	if id == "" {
@@ -319,6 +414,10 @@ func (s *defaultOpenAIWSStateStore) maybeCleanup() {
 	cleanupExpiredAccountBindings(s.responseToAccount, now, openAIWSStateStoreCleanupMaxPerMap)
 	s.responseToAccountMu.Unlock()
 
+	s.responseOwnerMu.Lock()
+	cleanupExpiredHTTPResponseOwnerBindings(s.responseOwners, now, openAIWSStateStoreCleanupMaxPerMap)
+	s.responseOwnerMu.Unlock()
+
 	s.responseToConnMu.Lock()
 	cleanupExpiredConnBindings(s.responseToConn, now, openAIWSStateStoreCleanupMaxPerMap)
 	s.responseToConnMu.Unlock()
@@ -419,6 +518,11 @@ func openAIWSResponseAccountCacheKey(responseID string) string {
 	return openAIWSResponseAccountCachePrefix + hex.EncodeToString(sum[:])
 }
 
+func openAIHTTPResponseOwnerCacheKey(prefix, responseID string) string {
+	sum := sha256.Sum256([]byte(responseID))
+	return prefix + hex.EncodeToString(sum[:])
+}
+
 // openAIWSResponseAccountMapKey 本地热缓存按分组隔离的 key，与 Redis 层保持一致，避免跨组命中。
 func openAIWSResponseAccountMapKey(groupID int64, responseID string) string {
 	return fmt.Sprintf("%d:%s", groupID, responseID)
diff --git a/backend/internal/service/openai_ws_state_store_test.go b/backend/internal/service/openai_ws_state_store_test.go
index 869e5e0fd6..6b20a95507 100644
--- a/backend/internal/service/openai_ws_state_store_test.go
+++ b/backend/internal/service/openai_ws_state_store_test.go
@@ -28,6 +28,27 @@ func TestOpenAIWSStateStore_BindGetDeleteResponseAccount(t *testing.T) {
 	require.Zero(t, accountID)
 }
 
+func TestOpenAIWSStateStore_HTTPResponseOwnerPersistsAcrossStoreInstances(t *testing.T) {
+	cache := &stubGatewayCache{}
+	ctx := context.Background()
+	groupID := int64(8)
+	writer := NewOpenAIWSStateStore(cache)
+
+	require.NoError(t, writer.BindHTTPResponseOwner(ctx, groupID, "resp_owned", 201, 301, time.Minute))
+	userID, apiKeyID, found, err := writer.GetHTTPResponseOwner(ctx, groupID, "resp_owned")
+	require.NoError(t, err)
+	require.True(t, found)
+	require.Equal(t, int64(201), userID)
+	require.Equal(t, int64(301), apiKeyID)
+
+	reader := NewOpenAIWSStateStore(cache)
+	userID, apiKeyID, found, err = reader.GetHTTPResponseOwner(ctx, groupID, "resp_owned")
+	require.NoError(t, err)
+	require.True(t, found)
+	require.Equal(t, int64(201), userID)
+	require.Equal(t, int64(301), apiKeyID)
+}
+
 func TestOpenAIWSStateStore_ResponseConnTTL(t *testing.T) {
 	store := NewOpenAIWSStateStore(nil)
 	store.BindResponseConn("resp_conn", "conn_1", 30*time.Millisecond)
diff --git a/backend/internal/service/openai_ws_v2/passthrough_relay.go b/backend/internal/service/openai_ws_v2/passthrough_relay.go
index e5e2633644..67c26f3e96 100644
--- a/backend/internal/service/openai_ws_v2/passthrough_relay.go
+++ b/backend/internal/service/openai_ws_v2/passthrough_relay.go
@@ -270,30 +270,34 @@ func Relay(
 	if !options.StartClientAfterFirstDownstream {
 		startClientReader()
 	}
-	go runUpstreamToClient(
-		relayCtx,
-		upstreamConn,
-		writeClient,
-		startAt,
-		nowFn,
-		state,
-		options.OnUsageParseFailure,
-		options.OnTurnComplete,
-		options.BeforeWriteClient,
-		options.BeforeClientWrite,
-		options.AfterClientWrite,
-		func(msgType coderws.MessageType, payload []byte) {
-			if options.StartClientAfterFirstDownstream {
-				startClientReader()
-			}
-		},
-		&dropDownstreamWrites,
-		upstreamToClientFrames,
-		droppedDownstreamFrames,
-		markActivity,
-		onTrace,
-		exitCh,
-	)
+	upstreamDone := make(chan struct{})
+	go func() {
+		defer close(upstreamDone)
+		runUpstreamToClient(
+			relayCtx,
+			upstreamConn,
+			writeClient,
+			startAt,
+			nowFn,
+			state,
+			options.OnUsageParseFailure,
+			options.OnTurnComplete,
+			options.BeforeWriteClient,
+			options.BeforeClientWrite,
+			options.AfterClientWrite,
+			func(msgType coderws.MessageType, payload []byte) {
+				if options.StartClientAfterFirstDownstream {
+					startClientReader()
+				}
+			},
+			&dropDownstreamWrites,
+			upstreamToClientFrames,
+			droppedDownstreamFrames,
+			markActivity,
+			onTrace,
+			exitCh,
+		)
+	}()
 	go runIdleWatchdog(relayCtx, nowFn, options.IdleTimeout, &lastActivity, onTrace, exitCh)
 
 	firstExit := <-exitCh
@@ -347,6 +351,10 @@ func Relay(
 
 	relayCancel()
 	_ = upstreamConn.Close()
+	// ReadFrame observes relayCtx cancellation and Close is the transport-level
+	// fallback. Join the reader before touching relayState or firing the final
+	// turn callback; otherwise a late read can race Relay's result settlement.
+	<-upstreamDone
 
 	emitTurnComplete(options.OnTurnComplete, state, finalizePendingBareError(state, nowFn()))
 	enrichResult(&result, state, nowFn().Sub(startAt))
diff --git a/backend/internal/service/openai_ws_v2/passthrough_relay_test.go b/backend/internal/service/openai_ws_v2/passthrough_relay_test.go
index 3bca8bf0ab..28b896f248 100644
--- a/backend/internal/service/openai_ws_v2/passthrough_relay_test.go
+++ b/backend/internal/service/openai_ws_v2/passthrough_relay_test.go
@@ -41,6 +41,16 @@ type closeSpyFrameConn struct {
 	closeCalls atomic.Int32
 }
 
+type cancelJoinProbeFrameConn struct {
+	readStarted  chan struct{}
+	readCanceled chan struct{}
+	allowReturn  chan struct{}
+	readReturned chan struct{}
+	startOnce    sync.Once
+	cancelOnce   sync.Once
+	returnOnce   sync.Once
+}
+
 func newPassthroughTestFrameConn(frames []passthroughTestFrame, autoClose bool) *passthroughTestFrameConn {
 	c := &passthroughTestFrameConn{
 		readCh: make(chan passthroughTestFrame, len(frames)+1),
@@ -179,6 +189,38 @@ func (c *closeSpyFrameConn) CloseCalls() int32 {
 	return c.closeCalls.Load()
 }
 
+func newCancelJoinProbeFrameConn() *cancelJoinProbeFrameConn {
+	return &cancelJoinProbeFrameConn{
+		readStarted:  make(chan struct{}),
+		readCanceled: make(chan struct{}),
+		allowReturn:  make(chan struct{}),
+		readReturned: make(chan struct{}),
+	}
+}
+
+func (c *cancelJoinProbeFrameConn) ReadFrame(ctx context.Context) (coderws.MessageType, []byte, error) {
+	c.startOnce.Do(func() { close(c.readStarted) })
+	<-ctx.Done()
+	c.cancelOnce.Do(func() { close(c.readCanceled) })
+	<-c.allowReturn
+	c.returnOnce.Do(func() { close(c.readReturned) })
+	return coderws.MessageText, nil, ctx.Err()
+}
+
+func (c *cancelJoinProbeFrameConn) WriteFrame(ctx context.Context, _ coderws.MessageType, _ []byte) error {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+		return nil
+	}
+}
+
+func (c *cancelJoinProbeFrameConn) Close() error { return nil }
+
 func TestRelay_BasicRelayAndUsage(t *testing.T) {
 	t.Parallel()
 
@@ -372,6 +414,58 @@ func TestRelay_IdleTimeoutDoesNotCloseClientOnError(t *testing.T) {
 	require.GreaterOrEqual(t, upstreamConn.CloseCalls(), int32(1))
 }
 
+func TestRelay_JoinsUpstreamReaderBeforeReturning(t *testing.T) {
+	t.Parallel()
+
+	clientConn := &closeSpyFrameConn{}
+	upstreamConn := newCancelJoinProbeFrameConn()
+	ctx, cancel := context.WithCancel(context.Background())
+	resultCh := make(chan *RelayExit, 1)
+
+	go func() {
+		_, relayExit := Relay(
+			ctx,
+			clientConn,
+			upstreamConn,
+			[]byte(`{"type":"response.create","model":"gpt-4o","input":[]}`),
+			RelayOptions{},
+		)
+		resultCh <- relayExit
+	}()
+
+	select {
+	case <-upstreamConn.readStarted:
+	case <-time.After(time.Second):
+		t.Fatal("upstream reader did not start")
+	}
+	cancel()
+	select {
+	case <-upstreamConn.readCanceled:
+	case <-time.After(time.Second):
+		t.Fatal("upstream reader did not observe relay cancellation")
+	}
+	select {
+	case <-resultCh:
+		t.Fatal("Relay returned before the upstream reader exited")
+	case <-time.After(50 * time.Millisecond):
+	}
+
+	close(upstreamConn.allowReturn)
+	select {
+	case relayExit := <-resultCh:
+		require.NotNil(t, relayExit)
+		require.ErrorIs(t, relayExit.Err, context.Canceled)
+	case <-time.After(time.Second):
+		t.Fatal("Relay did not return after the upstream reader exited")
+	}
+	select {
+	case <-upstreamConn.readReturned:
+	default:
+		t.Fatal("Relay returned before the upstream reader completion signal")
+	}
+	require.Zero(t, clientConn.CloseCalls(), "错误路径不应提前关闭客户端连接")
+}
+
 func TestRelay_NilConnections(t *testing.T) {
 	t.Parallel()
 
diff --git a/backend/internal/service/ops_upstream_context.go b/backend/internal/service/ops_upstream_context.go
index b4919b7809..509620fa1b 100644
--- a/backend/internal/service/ops_upstream_context.go
+++ b/backend/internal/service/ops_upstream_context.go
@@ -388,7 +388,9 @@ type OpsUpstreamErrorEvent struct {
 	Detail  string `json:"detail,omitempty"`
 
 	// SkipMonitoring is request-local rule state. It is intentionally excluded
-	// from persisted attempt JSON and only lets the final attempt control Ops.
+	// from persisted attempt JSON. The logger consults it only when this event is
+	// the final client-visible failure; recovered attempts remain provider-health
+	// telemetry and do not count as failed requests.
 	SkipMonitoring bool `json:"-"`
 }
 
@@ -427,11 +429,10 @@ func appendOpsUpstreamError(c *gin.Context, ev OpsUpstreamErrorEvent) {
 	checkSkipMonitoringForUpstreamEvent(c, &evCopy)
 }
 
-// checkSkipMonitoringForUpstreamEvent checks whether the upstream error event
-// matches a passthrough rule with skip_monitoring=true and, if so, sets the
-// OpsSkipPassthroughKey on the context.  This ensures intermediate retry /
-// failover errors (which never go through the final applyErrorPassthroughRule
-// path) can still suppress ops_error_logs recording.
+// checkSkipMonitoringForUpstreamEvent snapshots whether this attempt matches a
+// skip_monitoring passthrough rule. The final failure decides whether the
+// request error is hidden; an intermediate recovered attempt cannot suppress a
+// later client-visible failure.
 func checkSkipMonitoringForUpstreamEvent(c *gin.Context, ev *OpsUpstreamErrorEvent) {
 	if ev.UpstreamStatusCode == 0 {
 		return
diff --git a/backend/internal/service/temp_unsched.go b/backend/internal/service/temp_unsched.go
index 9b120c5775..92b7da3f72 100644
--- a/backend/internal/service/temp_unsched.go
+++ b/backend/internal/service/temp_unsched.go
@@ -29,7 +29,6 @@ type TempUnschedCache interface {
 // aggregate pool API-key failures across gateway instances.
 type OpenAIAPIKeyHealthCache interface {
 	RecordOpenAIAPIKeyHealthFailure(ctx context.Context, accountID int64, windowMinutes, threshold int) (count int64, tripped bool, err error)
-	ResetOpenAIAPIKeyHealthFailures(ctx context.Context, accountID int64) error
 }
 
 // TimeoutCounterCache 超时计数器缓存接口