fix(openai): record actual upstream endpoint on errors

backend/internal/handler/endpoint.go

@@ -312,6 +312,14 @@ func GetInboundEndpoint(c *gin.Context) string {
 // and the account platform. Handlers call this after scheduling an
 // account, passing account.Platform.
 func GetUpstreamEndpoint(c *gin.Context, platform string) string {
+	// OpenAI 转发服务维护独立的运行时端点上下文，覆盖普通入站推导。
+	// 这对 force_chat_completions 的错误路径尤为重要：此时可能没有
+	// ForwardResult，不能把入站 /v1/responses 误报成上游端点。
+	if platform == service.PlatformOpenAI || platform == service.PlatformGrok || service.IsCNProvider(platform) {
+		if endpoint := service.GetActualOpenAIUpstreamEndpoint(c); endpoint != "" {
+			return endpoint
+		}
+	}
 	if c != nil {
 		if value, ok := c.Get(ctxKeyActualUpstreamEndpoint); ok {
 			if endpoint, ok := value.(string); ok && endpoint != "" {

backend/internal/handler/endpoint_test.go

@@ -184,6 +184,16 @@ func TestGetUpstreamEndpointPrefersRuntimeOverride(t *testing.T) {
 	require.Equal(t, EndpointMessages, GetUpstreamEndpoint(c, service.PlatformAntigravity))
 }
 
+func TestGetUpstreamEndpointUsesOpenAIRuntimeOverride(t *testing.T) {
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, EndpointResponses, nil)
+	c.Set(ctxKeyInboundEndpoint, EndpointResponses)
+
+	service.SetActualOpenAIUpstreamEndpoint(c, EndpointChatCompletions)
+	require.Equal(t, EndpointChatCompletions, GetUpstreamEndpoint(c, service.PlatformOpenAI))
+}
+
 func TestResolveOpenAIUpstreamEndpointPrefersForwardResult(t *testing.T) {
 	tests := []struct {
 		name            string

backend/internal/service/openai_gateway_cc_pipeline.go

@@ -186,6 +186,10 @@ func (s *OpenAIGatewayService) sendCCUpstreamRequest(
 	if err != nil {
 		return nil, fmt.Errorf("build upstream request: %w", err)
 	}
+	// 记录本次实际选择的协议端点，供错误日志和用量日志在没有
+	// OpenAIForwardResult（例如 503/传输失败）时使用。每次发送都覆盖，
+	// 避免 Gin context 在账号 failover 尝试之间残留旧端点。
+	SetActualOpenAIUpstreamEndpoint(c, "/v1/chat/completions")
 	upstreamReq = upstreamReq.WithContext(WithHTTPUpstreamProfile(upstreamReq.Context(), HTTPUpstreamProfileOpenAI))
 	upstreamReq.Header.Set("Content-Type", "application/json")
 	upstreamReq.Header.Set("Authorization", "Bearer "+bearerToken)

backend/internal/service/openai_gateway_chat_completions.go

@@ -60,6 +60,10 @@ func (s *OpenAIGatewayService) ForwardAsChatCompletions(
 	defaultMappedModel string,
 ) (*OpenAIForwardResult, error) {
 	beginUpstreamResponseModelObservation(c)
+	ClearActualOpenAIUpstreamEndpoint(c)
+	if shouldForwardOpenAIResponsesViaRawChatCompletions(account) {
+		SetActualOpenAIUpstreamEndpoint(c, "/v1/chat/completions")
+	}
 	setCodexToolNameReverse(c, nil)
 	if _, err := s.prepareCodexAccountIdentitySource(ctx, c, account); err != nil {
 		return nil, err

backend/internal/service/openai_gateway_forward.go

@@ -20,6 +20,10 @@ import (
 // Forward forwards request to OpenAI API
 func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, account *Account, body []byte) (*OpenAIForwardResult, error) {
 	beginUpstreamResponseModelObservation(c)
+	ClearActualOpenAIUpstreamEndpoint(c)
+	if shouldForwardOpenAIResponsesViaRawChatCompletions(account) {
+		SetActualOpenAIUpstreamEndpoint(c, "/v1/chat/completions")
+	}
 	clearGrokResponsesClientToolMapping(c)
 	clearOpenAIResponsesClientToolMapping(c)
 	clearOpenAIResponsesNamespaceNames(c)

backend/internal/service/openai_gateway_messages.go

@@ -34,6 +34,10 @@ func (s *OpenAIGatewayService) ForwardAsAnthropic(
 	defaultMappedModel string,
 ) (*OpenAIForwardResult, error) {
 	beginUpstreamResponseModelObservation(c)
+	ClearActualOpenAIUpstreamEndpoint(c)
+	if shouldForwardOpenAIResponsesViaRawChatCompletions(account) {
+		SetActualOpenAIUpstreamEndpoint(c, "/v1/chat/completions")
+	}
 	setCodexToolNameReverse(c, nil)
 	if _, err := s.prepareCodexAccountIdentitySource(ctx, c, account); err != nil {
 		return nil, err

backend/internal/service/openai_gateway_responses_chat_fallback_test.go

@@ -39,11 +39,13 @@ func TestForwardResponses_ForceChatCompletionsRoutesNonStreamingToChatCompletion
 		cfg:          rawChatCompletionsTestConfig(),
 		httpUpstream: upstream,
 	}
+	SetActualOpenAIUpstreamEndpoint(c, "/v1/responses")
 
 	result, err := svc.Forward(context.Background(), c, forceChatResponsesFallbackAccount(), body)
 	require.NoError(t, err)
 	require.NotNil(t, result)
 	require.Equal(t, "http://upstream.example/v1/chat/completions", upstream.lastReq.URL.String())
+	require.Equal(t, "/v1/chat/completions", GetActualOpenAIUpstreamEndpoint(c))
 	require.Equal(t, HTTPUpstreamProfileOpenAI, HTTPUpstreamProfileFromContext(upstream.lastReq.Context()))
 	require.Equal(t, "hello", gjson.GetBytes(upstream.lastBody, "messages.0.content").String())
 	require.False(t, gjson.GetBytes(upstream.lastBody, "input").Exists())

backend/internal/service/openai_gateway_service.go

@@ -319,6 +319,16 @@ func SetActualOpenAIUpstreamEndpoint(c *gin.Context, endpoint string) {
 	}
 }
 
+// ClearActualOpenAIUpstreamEndpoint 清理当前转发尝试记录的端点。
+// Handler 会在账号 failover 尝试间复用同一个 Gin context，因此每次尝试
+// 都必须从无残留状态开始。
+func ClearActualOpenAIUpstreamEndpoint(c *gin.Context) {
+	if c == nil {
+		return
+	}
+	c.Set(openAIUpstreamEndpointContextKey, "")
+}
+
 // GetActualOpenAIUpstreamEndpoint returns the endpoint recorded by the latest
 // forwarding attempt in this request.
 func GetActualOpenAIUpstreamEndpoint(c *gin.Context) string {