diff --git a/backend/internal/handler/auth_handler.go b/backend/internal/handler/auth_handler.go
index 0b8d5e15..75ea9f08 100644
--- a/backend/internal/handler/auth_handler.go
+++ b/backend/internal/handler/auth_handler.go
@@ -409,6 +409,7 @@ func (h *AuthHandler) ValidateInvitationCode(c *gin.Context) {
 		Valid: true,
 	})
 }
+
 // ForgotPasswordRequest 忘记密码请求
 type ForgotPasswordRequest struct {
 	Email          string `json:"email" binding:"required,email"`
diff --git a/backend/internal/handler/dto/mappers.go b/backend/internal/handler/dto/mappers.go
index c22d8100..4cdb99fe 100644
--- a/backend/internal/handler/dto/mappers.go
+++ b/backend/internal/handler/dto/mappers.go
@@ -105,12 +105,12 @@ func GroupFromServiceAdmin(g *service.Group) *AdminGroup {
 		return nil
 	}
 	out := &AdminGroup{
-		Group:               groupFromServiceBase(g),
-		ModelRouting:        g.ModelRouting,
-		ModelRoutingEnabled: g.ModelRoutingEnabled,
-		MCPXMLInject:        g.MCPXMLInject,
+		Group:                groupFromServiceBase(g),
+		ModelRouting:         g.ModelRouting,
+		ModelRoutingEnabled:  g.ModelRoutingEnabled,
+		MCPXMLInject:         g.MCPXMLInject,
 		SupportedModelScopes: g.SupportedModelScopes,
-		AccountCount:        g.AccountCount,
+		AccountCount:         g.AccountCount,
 	}
 	if len(g.AccountGroups) > 0 {
 		out.AccountGroups = make([]AccountGroup, 0, len(g.AccountGroups))
@@ -142,8 +142,8 @@ func groupFromServiceBase(g *service.Group) Group {
 		FallbackGroupID:  g.FallbackGroupID,
 		// 无效请求兜底分组
 		FallbackGroupIDOnInvalidRequest: g.FallbackGroupIDOnInvalidRequest,
-		CreatedAt:        g.CreatedAt,
-		UpdatedAt:        g.UpdatedAt,
+		CreatedAt:                       g.CreatedAt,
+		UpdatedAt:                       g.UpdatedAt,
 	}
 }
 
diff --git a/backend/internal/handler/dto/types.go b/backend/internal/handler/dto/types.go
index ecfbb7c2..1099e1f6 100644
--- a/backend/internal/handler/dto/types.go
+++ b/backend/internal/handler/dto/types.go
@@ -89,9 +89,9 @@ type AdminGroup struct {
 	MCPXMLInject bool `json:"mcp_xml_inject"`
 
 	// 支持的模型系列（仅 antigravity 平台使用）
-	SupportedModelScopes []string `json:"supported_model_scopes"`
-	AccountGroups []AccountGroup `json:"account_groups,omitempty"`
-	AccountCount  int64          `json:"account_count,omitempty"`
+	SupportedModelScopes []string       `json:"supported_model_scopes"`
+	AccountGroups        []AccountGroup `json:"account_groups,omitempty"`
+	AccountCount         int64          `json:"account_count,omitempty"`
 }
 
 type Account struct {
diff --git a/backend/internal/server/api_contract_test.go b/backend/internal/server/api_contract_test.go
index d6b2f1b8..28a00fa3 100644
--- a/backend/internal/server/api_contract_test.go
+++ b/backend/internal/server/api_contract_test.go
@@ -180,6 +180,7 @@ func TestAPIContracts(t *testing.T) {
 						"image_price_4k": null,
 						"claude_code_only": false,
 						"fallback_group_id": null,
+						"fallback_group_id_on_invalid_request": null,
 						"created_at": "2025-01-02T03:04:05Z",
 						"updated_at": "2025-01-02T03:04:05Z"
 					}
@@ -600,8 +601,8 @@ func newContractDeps(t *testing.T) *contractDeps {
 	settingRepo := newStubSettingRepo()
 	settingService := service.NewSettingService(settingRepo, cfg)
 
-adminService := service.NewAdminService(userRepo, groupRepo, &accountRepo, proxyRepo, apiKeyRepo, redeemRepo, nil, nil, nil, nil)
-authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil, redeemService, nil)
+	adminService := service.NewAdminService(userRepo, groupRepo, &accountRepo, proxyRepo, apiKeyRepo, redeemRepo, nil, nil, nil, nil)
+	authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil, redeemService, nil)
 	apiKeyHandler := handler.NewAPIKeyHandler(apiKeyService)
 	usageHandler := handler.NewUsageHandler(usageService, apiKeyService)
 	adminSettingHandler := adminhandler.NewSettingHandler(settingService, nil, nil, nil)
diff --git a/backend/internal/service/admin_service_group_test.go b/backend/internal/service/admin_service_group_test.go
index 9b8c0107..d921a086 100644
--- a/backend/internal/service/admin_service_group_test.go
+++ b/backend/internal/service/admin_service_group_test.go
@@ -458,6 +458,14 @@ func (s *groupRepoStubForInvalidRequestFallback) DeleteAccountGroupsByGroupID(_
 	panic("unexpected DeleteAccountGroupsByGroupID call")
 }
 
+func (s *groupRepoStubForInvalidRequestFallback) GetAccountIDsByGroupIDs(_ context.Context, _ []int64) ([]int64, error) {
+	panic("unexpected GetAccountIDsByGroupIDs call")
+}
+
+func (s *groupRepoStubForInvalidRequestFallback) BindAccountsToGroup(_ context.Context, _ int64, _ []int64) error {
+	panic("unexpected BindAccountsToGroup call")
+}
+
 func TestAdminService_CreateGroup_InvalidRequestFallbackRejectsUnsupportedPlatform(t *testing.T) {
 	fallbackID := int64(10)
 	repo := &groupRepoStubForInvalidRequestFallback{
@@ -764,4 +772,4 @@ func TestAdminService_UpdateGroup_InvalidRequestFallbackAllowsAntigravity(t *tes
 	require.NotNil(t, group)
 	require.NotNil(t, repo.updated)
 	require.Equal(t, fallbackID, *repo.updated.FallbackGroupIDOnInvalidRequest)
-	}
+}
diff --git a/backend/internal/service/antigravity_gateway_service.go b/backend/internal/service/antigravity_gateway_service.go
index 687d7ea0..d16c4259 100644
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -2046,6 +2046,9 @@ func (s *AntigravityGatewayService) handleUpstreamError(ctx context.Context, pre
 				fallbackMinutes = s.settingService.cfg.Gateway.AntigravityFallbackCooldownMinutes
 			}
 			defaultDur := time.Duration(fallbackMinutes) * time.Minute
+			if fallbackDur, ok := antigravityFallbackCooldownSeconds(); ok {
+				defaultDur = fallbackDur
+			}
 			ra := time.Now().Add(defaultDur)
 			if useScopeLimit {
 				log.Printf("%s status=429 rate_limited scope=%s reset_in=%v (fallback)", prefix, quotaScope, defaultDur)