feat(openai): support GPT-5.6 cache write billing

backend/internal/pkg/apicompat/chatcompletions_responses_bridge.go

@@ -608,9 +608,17 @@ func ChatUsageToResponsesUsage(usage *ChatUsage) *ResponsesUsage {
 	if out.TotalTokens == 0 {
 		out.TotalTokens = out.InputTokens + out.OutputTokens
 	}
-	if usage.PromptTokensDetails != nil && usage.PromptTokensDetails.CachedTokens > 0 {
+	if usage.PromptTokensDetails != nil && (usage.PromptTokensDetails.CachedTokens > 0 ||
+		usage.PromptTokensDetails.CacheCreationTokens > 0 || usage.PromptTokensDetails.CacheWriteTokens > 0) {
 		out.InputTokensDetails = &ResponsesInputTokensDetails{
-			CachedTokens: usage.PromptTokensDetails.CachedTokens,
+			CachedTokens:        usage.PromptTokensDetails.CachedTokens,
+			CacheCreationTokens: usage.PromptTokensDetails.CacheCreationTokens,
+			CacheWriteTokens:    usage.PromptTokensDetails.CacheWriteTokens,
+		}
+		if usage.PromptTokensDetails.CacheWriteTokens > 0 {
+			out.CacheCreationInputTokens = usage.PromptTokensDetails.CacheWriteTokens
+		} else {
+			out.CacheCreationInputTokens = usage.PromptTokensDetails.CacheCreationTokens
 		}
 	}
 	return out

backend/internal/pkg/apicompat/chatcompletions_responses_test.go

@@ -32,6 +32,27 @@ func TestChatCompletionsToResponses_BasicText(t *testing.T) {
 	assert.Equal(t, "user", items[0].Role)
 }
 
+func TestUsageConversionsPreserveCacheWriteTokens(t *testing.T) {
+	var responsesUsage ResponsesUsage
+	require.NoError(t, json.Unmarshal([]byte(`{
+		"input_tokens":1000,
+		"output_tokens":50,
+		"input_tokens_details":{"cached_tokens":100,"cache_write_tokens":200}
+	}`), &responsesUsage))
+	require.NotNil(t, responsesUsage.InputTokensDetails)
+	require.Equal(t, 200, responsesUsage.InputTokensDetails.CacheWriteTokens)
+
+	chatUsage := chatUsageFromResponsesUsage(&responsesUsage)
+	require.NotNil(t, chatUsage.PromptTokensDetails)
+	require.Equal(t, 100, chatUsage.PromptTokensDetails.CachedTokens)
+	require.Equal(t, 200, chatUsage.PromptTokensDetails.CacheWriteTokens)
+
+	roundTrip := ChatUsageToResponsesUsage(chatUsage)
+	require.NotNil(t, roundTrip.InputTokensDetails)
+	require.Equal(t, 200, roundTrip.CacheCreationInputTokens)
+	require.Equal(t, 200, roundTrip.InputTokensDetails.CacheWriteTokens)
+}
+
 func TestChatCompletionsToResponses_SystemMessage(t *testing.T) {
 	req := &ChatCompletionsRequest{
 		Model: "gpt-4o",

backend/internal/pkg/apicompat/responses_to_chatcompletions.go

@@ -338,6 +338,14 @@ func chatUsageFromResponsesUsage(u *ResponsesUsage) *ChatUsage {
 		TotalTokens:      u.InputTokens + u.OutputTokens,
 	}
 	usage.PromptTokensDetails = promptDetailsFromResponses(u.InputTokensDetails)
+	if u.CacheCreationInputTokens > 0 {
+		if usage.PromptTokensDetails == nil {
+			usage.PromptTokensDetails = &ChatTokenDetails{}
+		}
+		if usage.PromptTokensDetails.CacheWriteTokens == 0 && usage.PromptTokensDetails.CacheCreationTokens == 0 {
+			usage.PromptTokensDetails.CacheCreationTokens = u.CacheCreationInputTokens
+		}
+	}
 	usage.CompletionTokensDetails = completionDetailsFromResponses(u.OutputTokensDetails)
 	return usage
 }
@@ -349,12 +357,14 @@ func promptDetailsFromResponses(src *ResponsesInputTokensDetails) *ChatTokenDeta
 	if src == nil {
 		return nil
 	}
-	if src.CachedTokens == 0 && src.AudioTokens == 0 {
+	if src.CachedTokens == 0 && src.AudioTokens == 0 && src.CacheCreationTokens == 0 && src.CacheWriteTokens == 0 {
 		return nil
 	}
 	return &ChatTokenDetails{
-		CachedTokens: src.CachedTokens,
-		AudioTokens:  src.AudioTokens,
+		CachedTokens:        src.CachedTokens,
+		AudioTokens:         src.AudioTokens,
+		CacheCreationTokens: src.CacheCreationTokens,
+		CacheWriteTokens:    src.CacheWriteTokens,
 	}
 }
 

backend/internal/pkg/apicompat/types.go

@@ -320,9 +320,10 @@ type ResponsesSummary struct {
 
 // ResponsesUsage holds token counts in Responses API format.
 type ResponsesUsage struct {
-	InputTokens  int `json:"input_tokens"`
-	OutputTokens int `json:"output_tokens"`
-	TotalTokens  int `json:"total_tokens"`
+	InputTokens              int `json:"input_tokens"`
+	OutputTokens             int `json:"output_tokens"`
+	TotalTokens              int `json:"total_tokens"`
+	CacheCreationInputTokens int `json:"cache_creation_input_tokens,omitempty"`
 
 	// Optional detailed breakdown
 	InputTokensDetails  *ResponsesInputTokensDetails  `json:"input_tokens_details,omitempty"`
@@ -335,6 +336,9 @@ func (u *ResponsesUsage) UnmarshalJSON(data []byte) error {
 		responsesUsageAlias
 		PromptTokens            int                           `json:"prompt_tokens"`
 		CompletionTokens        int                           `json:"completion_tokens"`
+		CacheCreationTokens     int                           `json:"cache_creation_tokens"`
+		CacheWriteInputTokens   int                           `json:"cache_write_input_tokens"`
+		CacheWriteTokens        int                           `json:"cache_write_tokens"`
 		PromptTokensDetails     *ResponsesInputTokensDetails  `json:"prompt_tokens_details,omitempty"`
 		CompletionTokensDetails *ResponsesOutputTokensDetails `json:"completion_tokens_details,omitempty"`
 	}
@@ -348,6 +352,16 @@ func (u *ResponsesUsage) UnmarshalJSON(data []byte) error {
 	if u.OutputTokens == 0 && aux.CompletionTokens != 0 {
 		u.OutputTokens = aux.CompletionTokens
 	}
+	if u.CacheCreationInputTokens == 0 {
+		switch {
+		case aux.CacheWriteInputTokens > 0:
+			u.CacheCreationInputTokens = aux.CacheWriteInputTokens
+		case aux.CacheCreationTokens > 0:
+			u.CacheCreationInputTokens = aux.CacheCreationTokens
+		case aux.CacheWriteTokens > 0:
+			u.CacheCreationInputTokens = aux.CacheWriteTokens
+		}
+	}
 	if u.InputTokensDetails == nil && aux.PromptTokensDetails != nil {
 		u.InputTokensDetails = aux.PromptTokensDetails
 	}
@@ -362,8 +376,10 @@ func (u *ResponsesUsage) UnmarshalJSON(data []byte) error {
 
 // ResponsesInputTokensDetails breaks down input token usage.
 type ResponsesInputTokensDetails struct {
-	CachedTokens int `json:"cached_tokens,omitempty"`
-	AudioTokens  int `json:"audio_tokens,omitempty"`
+	CachedTokens        int `json:"cached_tokens,omitempty"`
+	AudioTokens         int `json:"audio_tokens,omitempty"`
+	CacheCreationTokens int `json:"cache_creation_tokens,omitempty"`
+	CacheWriteTokens    int `json:"cache_write_tokens,omitempty"`
 }
 
 // ResponsesOutputTokensDetails breaks down output token usage.
@@ -545,6 +561,8 @@ type ChatUsage struct {
 type ChatTokenDetails struct {
 	CachedTokens             int `json:"cached_tokens,omitempty"`
 	AudioTokens              int `json:"audio_tokens,omitempty"`
+	CacheCreationTokens      int `json:"cache_creation_tokens,omitempty"`
+	CacheWriteTokens         int `json:"cache_write_tokens,omitempty"`
 	ReasoningTokens          int `json:"reasoning_tokens,omitempty"`
 	AcceptedPredictionTokens int `json:"accepted_prediction_tokens,omitempty"`
 	RejectedPredictionTokens int `json:"rejected_prediction_tokens,omitempty"`

backend/internal/service/billing_service.go

@@ -90,22 +90,23 @@ type BillingCache interface {
 
 // ModelPricing 模型价格配置（per-token价格，与LiteLLM格式一致）
 type ModelPricing struct {
-	InputPricePerToken             float64 // 每token输入价格 (USD)
-	InputPricePerTokenPriority     float64 // priority service tier 下每token输入价格 (USD)
-	ImageInputPricePerToken        float64 // 图片输入 token 价格 (USD)，用于多模态 embedding 等图文不同价场景；为 0 时回退到 InputPricePerToken
-	OutputPricePerToken            float64 // 每token输出价格 (USD)
-	OutputPricePerTokenPriority    float64 // priority service tier 下每token输出价格 (USD)
-	CacheCreationPricePerToken     float64 // 缓存创建每token价格 (USD)
-	CacheReadPricePerToken         float64 // 缓存读取每token价格 (USD)
-	CacheReadPricePerTokenPriority float64 // priority service tier 下缓存读取每token价格 (USD)
-	CacheCreation5mPrice           float64 // 5分钟缓存创建每token价格 (USD)
-	CacheCreation1hPrice           float64 // 1小时缓存创建每token价格 (USD)
-	SupportsCacheBreakdown         bool    // 是否支持详细的缓存分类
-	LongContextInputThreshold      int     // 超过阈值后按整次会话提升输入价格
-	LongContextInputMultiplier     float64 // 长上下文整次会话输入倍率
-	LongContextOutputMultiplier    float64 // 长上下文整次会话输出倍率
-	ImageOutputPricePerToken       float64 // 图片输出 token 价格 (USD)
-	ImageOutputPriceExplicit       bool    // 是否由渠道定价显式设定（为 true 时即使 == 0 也不回退）
+	InputPricePerToken                 float64 // 每token输入价格 (USD)
+	InputPricePerTokenPriority         float64 // priority service tier 下每token输入价格 (USD)
+	ImageInputPricePerToken            float64 // 图片输入 token 价格 (USD)，用于多模态 embedding 等图文不同价场景；为 0 时回退到 InputPricePerToken
+	OutputPricePerToken                float64 // 每token输出价格 (USD)
+	OutputPricePerTokenPriority        float64 // priority service tier 下每token输出价格 (USD)
+	CacheCreationPricePerToken         float64 // 缓存创建每token价格 (USD)
+	CacheCreationPricePerTokenPriority float64 // priority service tier 下缓存创建每token价格 (USD)
+	CacheReadPricePerToken             float64 // 缓存读取每token价格 (USD)
+	CacheReadPricePerTokenPriority     float64 // priority service tier 下缓存读取每token价格 (USD)
+	CacheCreation5mPrice               float64 // 5分钟缓存创建每token价格 (USD)
+	CacheCreation1hPrice               float64 // 1小时缓存创建每token价格 (USD)
+	SupportsCacheBreakdown             bool    // 是否支持详细的缓存分类
+	LongContextInputThreshold          int     // 超过阈值后按整次会话提升输入价格
+	LongContextInputMultiplier         float64 // 长上下文整次会话输入倍率
+	LongContextOutputMultiplier        float64 // 长上下文整次会话输出倍率
+	ImageOutputPricePerToken           float64 // 图片输出 token 价格 (USD)
+	ImageOutputPriceExplicit           bool    // 是否由渠道定价显式设定（为 true 时即使 == 0 也不回退）
 }
 
 const (
@@ -122,7 +123,8 @@ func usePriorityServiceTierPricing(serviceTier string, pricing *ModelPricing) bo
 	if pricing == nil || normalizeBillingServiceTier(serviceTier) != "priority" {
 		return false
 	}
-	return pricing.InputPricePerTokenPriority > 0 || pricing.OutputPricePerTokenPriority > 0 || pricing.CacheReadPricePerTokenPriority > 0
+	return pricing.InputPricePerTokenPriority > 0 || pricing.OutputPricePerTokenPriority > 0 ||
+		pricing.CacheCreationPricePerTokenPriority > 0 || pricing.CacheReadPricePerTokenPriority > 0
 }
 
 func serviceTierCostMultiplier(serviceTier string) float64 {
@@ -739,20 +741,21 @@ func (s *BillingService) GetModelPricing(model string) (*ModelPricing, error) {
 			price1h := litellmPricing.CacheCreationInputTokenCostAbove1hr
 			enableBreakdown := price1h > 0 && price1h > price5m
 			return s.applyModelSpecificPricingPolicy(model, &ModelPricing{
-				InputPricePerToken:             litellmPricing.InputCostPerToken,
-				InputPricePerTokenPriority:     litellmPricing.InputCostPerTokenPriority,
-				OutputPricePerToken:            litellmPricing.OutputCostPerToken,
-				OutputPricePerTokenPriority:    litellmPricing.OutputCostPerTokenPriority,
-				CacheCreationPricePerToken:     litellmPricing.CacheCreationInputTokenCost,
-				CacheReadPricePerToken:         litellmPricing.CacheReadInputTokenCost,
-				CacheReadPricePerTokenPriority: litellmPricing.CacheReadInputTokenCostPriority,
-				CacheCreation5mPrice:           price5m,
-				CacheCreation1hPrice:           price1h,
-				SupportsCacheBreakdown:         enableBreakdown,
-				LongContextInputThreshold:      litellmPricing.LongContextInputTokenThreshold,
-				LongContextInputMultiplier:     litellmPricing.LongContextInputCostMultiplier,
-				LongContextOutputMultiplier:    litellmPricing.LongContextOutputCostMultiplier,
-				ImageOutputPricePerToken:       litellmPricing.OutputCostPerImageToken,
+				InputPricePerToken:                 litellmPricing.InputCostPerToken,
+				InputPricePerTokenPriority:         litellmPricing.InputCostPerTokenPriority,
+				OutputPricePerToken:                litellmPricing.OutputCostPerToken,
+				OutputPricePerTokenPriority:        litellmPricing.OutputCostPerTokenPriority,
+				CacheCreationPricePerToken:         litellmPricing.CacheCreationInputTokenCost,
+				CacheCreationPricePerTokenPriority: litellmPricing.CacheCreationInputTokenCostPriority,
+				CacheReadPricePerToken:             litellmPricing.CacheReadInputTokenCost,
+				CacheReadPricePerTokenPriority:     litellmPricing.CacheReadInputTokenCostPriority,
+				CacheCreation5mPrice:               price5m,
+				CacheCreation1hPrice:               price1h,
+				SupportsCacheBreakdown:             enableBreakdown,
+				LongContextInputThreshold:          litellmPricing.LongContextInputTokenThreshold,
+				LongContextInputMultiplier:         litellmPricing.LongContextInputCostMultiplier,
+				LongContextOutputMultiplier:        litellmPricing.LongContextOutputCostMultiplier,
+				ImageOutputPricePerToken:           litellmPricing.OutputCostPerImageToken,
 			}), nil
 		}
 	}
@@ -794,6 +797,7 @@ func (s *BillingService) GetModelPricingWithChannel(model string, channelPricing
 	}
 	if channelPricing.CacheWritePrice != nil {
 		pricing.CacheCreationPricePerToken = *channelPricing.CacheWritePrice
+		pricing.CacheCreationPricePerTokenPriority = *channelPricing.CacheWritePrice
 		pricing.CacheCreation5mPrice = *channelPricing.CacheWritePrice
 		pricing.CacheCreation1hPrice = *channelPricing.CacheWritePrice
 	}
@@ -867,7 +871,7 @@ func (s *BillingService) CalculateCostUnified(input CostInput) (*CostBreakdown,
 
 // calculateTokenCost 按 token 区间计费
 func (s *BillingService) calculateTokenCost(resolved *ResolvedPricing, input CostInput) (*CostBreakdown, error) {
-	totalContext := input.Tokens.InputTokens + input.Tokens.CacheReadTokens
+	totalContext := input.Tokens.InputTokens + input.Tokens.CacheCreationTokens + input.Tokens.CacheReadTokens
 
 	pricing := input.Resolver.GetIntervalPricing(resolved, totalContext)
 	if pricing == nil {
@@ -897,6 +901,7 @@ func (s *BillingService) computeTokenBreakdown(
 	inputPrice := pricing.InputPricePerToken
 	outputPrice := pricing.OutputPricePerToken
 	cacheReadPrice := pricing.CacheReadPricePerToken
+	cacheCreationPrice := pricing.CacheCreationPricePerToken
 	cacheCreationMultiplier := 1.0
 	tierMultiplier := 1.0
 
@@ -910,6 +915,9 @@ func (s *BillingService) computeTokenBreakdown(
 		if pricing.CacheReadPricePerTokenPriority > 0 {
 			cacheReadPrice = pricing.CacheReadPricePerTokenPriority
 		}
+		if pricing.CacheCreationPricePerTokenPriority > 0 {
+			cacheCreationPrice = pricing.CacheCreationPricePerTokenPriority
+		}
 	} else {
 		tierMultiplier = serviceTierCostMultiplier(serviceTier)
 	}
@@ -963,7 +971,7 @@ func (s *BillingService) computeTokenBreakdown(
 	}
 
 	// 缓存创建费用
-	bd.CacheCreationCost = s.computeCacheCreationCost(pricing, tokens, cacheCreationMultiplier)
+	bd.CacheCreationCost = s.computeCacheCreationCost(pricing, tokens, cacheCreationPrice, cacheCreationMultiplier)
 
 	bd.CacheReadCost = float64(tokens.CacheReadTokens) * cacheReadPrice
 
@@ -984,7 +992,7 @@ func (s *BillingService) computeTokenBreakdown(
 
 // computeCacheCreationCost 计算缓存创建费用（支持 5m/1h 分类或标准计费）。
 // multiplier 用于长上下文等场景下的整体价格缩放（普通调用传 1.0 即可）。
-func (s *BillingService) computeCacheCreationCost(pricing *ModelPricing, tokens UsageTokens, multiplier float64) float64 {
+func (s *BillingService) computeCacheCreationCost(pricing *ModelPricing, tokens UsageTokens, price, multiplier float64) float64 {
 	if pricing.SupportsCacheBreakdown && (pricing.CacheCreation5mPrice > 0 || pricing.CacheCreation1hPrice > 0) {
 		if tokens.CacheCreation5mTokens == 0 && tokens.CacheCreation1hTokens == 0 && tokens.CacheCreationTokens > 0 {
 			// API 未返回 ephemeral 明细，回退到全部按 5m 单价计费
@@ -993,7 +1001,7 @@ func (s *BillingService) computeCacheCreationCost(pricing *ModelPricing, tokens
 		return float64(tokens.CacheCreation5mTokens)*pricing.CacheCreation5mPrice*multiplier +
 			float64(tokens.CacheCreation1hTokens)*pricing.CacheCreation1hPrice*multiplier
 	}
-	return float64(tokens.CacheCreationTokens) * pricing.CacheCreationPricePerToken * multiplier
+	return float64(tokens.CacheCreationTokens) * price * multiplier
 }
 
 // calculatePerRequestCost 按次/图片计费
@@ -1010,7 +1018,7 @@ func (s *BillingService) calculatePerRequestCost(resolved *ResolvedPricing, inpu
 	}
 
 	if unitPrice == 0 {
-		totalContext := input.Tokens.InputTokens + input.Tokens.CacheReadTokens
+		totalContext := input.Tokens.InputTokens + input.Tokens.CacheCreationTokens + input.Tokens.CacheReadTokens
 		unitPrice = input.Resolver.GetRequestTierPriceByContext(resolved, totalContext)
 	}
 
@@ -1057,13 +1065,26 @@ func (s *BillingService) applyModelSpecificPricingPolicy(model string, pricing *
 	if pricing == nil {
 		return nil
 	}
+	normalized := normalizeKnownOpenAICodexModel(model)
 	if !isOpenAIGPT54Model(model) {
 		return pricing
 	}
-	if pricing.LongContextInputThreshold > 0 && pricing.LongContextInputMultiplier > 0 && pricing.LongContextOutputMultiplier > 0 {
+	isGPT56 := normalized == "gpt-5.6-sol" || normalized == "gpt-5.6-terra" || normalized == "gpt-5.6-luna"
+	needsLongContextPolicy := pricing.LongContextInputThreshold <= 0 || pricing.LongContextInputMultiplier <= 0 || pricing.LongContextOutputMultiplier <= 0
+	needsCacheCreationPolicy := isGPT56 && (pricing.CacheCreationPricePerToken <= 0 ||
+		(pricing.InputPricePerTokenPriority > 0 && pricing.CacheCreationPricePerTokenPriority <= 0))
+	if !needsLongContextPolicy && !needsCacheCreationPolicy {
 		return pricing
 	}
 	cloned := *pricing
+	if isGPT56 {
+		if cloned.CacheCreationPricePerToken <= 0 {
+			cloned.CacheCreationPricePerToken = cloned.InputPricePerToken
+		}
+		if cloned.CacheCreationPricePerTokenPriority <= 0 {
+			cloned.CacheCreationPricePerTokenPriority = cloned.InputPricePerTokenPriority
+		}
+	}
 	if cloned.LongContextInputThreshold <= 0 {
 		cloned.LongContextInputThreshold = openAIGPT54LongContextInputThreshold
 	}
@@ -1083,7 +1104,7 @@ func (s *BillingService) shouldApplySessionLongContextPricing(tokens UsageTokens
 	if pricing.LongContextInputMultiplier <= 1 && pricing.LongContextOutputMultiplier <= 1 {
 		return false
 	}
-	totalInputTokens := tokens.InputTokens + tokens.CacheReadTokens
+	totalInputTokens := tokens.InputTokens + tokens.CacheCreationTokens + tokens.CacheReadTokens
 	return totalInputTokens > pricing.LongContextInputThreshold
 }
 

backend/internal/service/model_pricing_resolver.go

@@ -183,6 +183,7 @@ func (r *ModelPricingResolver) applyTokenOverrides(chPricing *ChannelModelPricin
 	}
 	if chPricing.CacheWritePrice != nil {
 		resolved.BasePricing.CacheCreationPricePerToken = *chPricing.CacheWritePrice
+		resolved.BasePricing.CacheCreationPricePerTokenPriority = *chPricing.CacheWritePrice
 		resolved.BasePricing.CacheCreation5mPrice = *chPricing.CacheWritePrice
 		resolved.BasePricing.CacheCreation1hPrice = *chPricing.CacheWritePrice
 	}
@@ -251,6 +252,7 @@ func intervalToModelPricing(iv *PricingInterval, supportsCacheBreakdown bool, ch
 	}
 	if iv.CacheWritePrice != nil {
 		pricing.CacheCreationPricePerToken = *iv.CacheWritePrice
+		pricing.CacheCreationPricePerTokenPriority = *iv.CacheWritePrice
 		pricing.CacheCreation5mPrice = *iv.CacheWritePrice
 		pricing.CacheCreation1hPrice = *iv.CacheWritePrice
 	}

backend/internal/service/openai_embeddings.go

@@ -206,17 +206,8 @@ func extractOpenAIEmbeddingsUsage(body []byte) OpenAIUsage {
 		usage.Get("completion_tokens"),
 		usage.Get("output_tokens"),
 	)
-	cacheReadTokens := firstPositiveGJSONInt(
-		usage.Get("prompt_tokens_details.cached_tokens"),
-		usage.Get("input_tokens_details.cached_tokens"),
-		usage.Get("cache_read_tokens"),
-		usage.Get("cache_read_input_tokens"),
-	)
-	cacheCreationTokens := firstPositiveGJSONInt(
-		usage.Get("cache_creation_tokens"),
-		usage.Get("cache_creation_input_tokens"),
-		usage.Get("input_tokens_details.cache_creation_tokens"),
-	)
+	cacheReadTokens := openAICacheReadTokensFromUsage(usage)
+	cacheCreationTokens := openAICacheCreationTokensFromUsage(usage)
 	// 多模态 embedding（如 doubao-embedding-vision）回传图文 token 拆分，
 	// 用于图文不同价计费；纯文本 embedding 该字段为 0，行为不变。
 	imageInputTokens := firstPositiveGJSONInt(

backend/internal/service/openai_gateway_chat_completions_raw.go

@@ -383,12 +383,9 @@ func extractCCStreamUsage(payload string) *OpenAIUsage {
 	if !usageResult.Exists() || !usageResult.IsObject() {
 		return nil
 	}
-	u := OpenAIUsage{
-		InputTokens:  int(gjson.Get(payload, "usage.prompt_tokens").Int()),
-		OutputTokens: int(gjson.Get(payload, "usage.completion_tokens").Int()),
-	}
-	if cached := gjson.Get(payload, "usage.prompt_tokens_details.cached_tokens"); cached.Exists() {
-		u.CacheReadInputTokens = int(cached.Int())
+	u, ok := openAIUsageFromGJSON(usageResult)
+	if !ok {
+		return nil
 	}
 	return &u
 }

backend/internal/service/openai_gateway_messages.go

@@ -1114,11 +1114,19 @@ func copyOpenAIUsageFromResponsesUsage(usage *apicompat.ResponsesUsage) OpenAIUs
 		return OpenAIUsage{}
 	}
 	result := OpenAIUsage{
-		InputTokens:  usage.InputTokens,
-		OutputTokens: usage.OutputTokens,
+		InputTokens:              usage.InputTokens,
+		OutputTokens:             usage.OutputTokens,
+		CacheCreationInputTokens: usage.CacheCreationInputTokens,
 	}
 	if usage.InputTokensDetails != nil {
 		result.CacheReadInputTokens = usage.InputTokensDetails.CachedTokens
+		if result.CacheCreationInputTokens == 0 {
+			if usage.InputTokensDetails.CacheWriteTokens > 0 {
+				result.CacheCreationInputTokens = usage.InputTokensDetails.CacheWriteTokens
+			} else {
+				result.CacheCreationInputTokens = usage.InputTokensDetails.CacheCreationTokens
+			}
+		}
 	}
 	return result
 }

backend/internal/service/openai_gateway_record_usage_test.go

@@ -247,7 +247,7 @@ func expectedOpenAICost(t *testing.T, svc *OpenAIGatewayService, model string, u
 	t.Helper()
 
 	cost, err := svc.billingService.CalculateCost(model, UsageTokens{
-		InputTokens:         max(usage.InputTokens-usage.CacheReadInputTokens, 0),
+		InputTokens:         max(usage.InputTokens-usage.CacheReadInputTokens-usage.CacheCreationInputTokens, 0),
 		OutputTokens:        usage.OutputTokens,
 		CacheCreationTokens: usage.CacheCreationInputTokens,
 		CacheReadTokens:     usage.CacheReadInputTokens,
@@ -1002,6 +1002,49 @@ func TestOpenAIGatewayServiceRecordUsage_ClampsActualInputTokensToZero(t *testin
 	require.Equal(t, 0, usageRepo.lastLog.InputTokens)
 }
 
+func TestOpenAIGatewayServiceRecordUsage_GPT56SeparatesCacheWriteForBillingAndStats(t *testing.T) {
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, nil)
+	svc.billingService = NewBillingService(svc.cfg, &PricingService{pricingData: map[string]*LiteLLMModelPricing{
+		"gpt-5.6-sol": {
+			InputCostPerToken:       5e-6,
+			OutputCostPerToken:      30e-6,
+			CacheReadInputTokenCost: 0.5e-6,
+		},
+	}})
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_gpt56_cache_write",
+			Usage: OpenAIUsage{
+				InputTokens:              1000,
+				OutputTokens:             50,
+				CacheCreationInputTokens: 200,
+				CacheReadInputTokens:     100,
+			},
+			Model:    "gpt-5.6-sol",
+			Duration: time.Second,
+		},
+		APIKey:  &APIKey{ID: 1056},
+		User:    &User{ID: 2056},
+		Account: &Account{ID: 3056},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, usageRepo.lastLog)
+	require.Equal(t, 700, usageRepo.lastLog.InputTokens)
+	require.Equal(t, 200, usageRepo.lastLog.CacheCreationTokens)
+	require.Equal(t, 100, usageRepo.lastLog.CacheReadTokens)
+	require.Equal(t, 1050, usageRepo.lastLog.TotalTokens())
+	require.InDelta(t, 700*5e-6, usageRepo.lastLog.InputCost, 1e-12)
+	require.InDelta(t, 200*5e-6, usageRepo.lastLog.CacheCreationCost, 1e-12)
+	require.InDelta(t, 100*0.5e-6, usageRepo.lastLog.CacheReadCost, 1e-12)
+	require.InDelta(t, 50*30e-6, usageRepo.lastLog.OutputCost, 1e-12)
+	require.InDelta(t, usageRepo.lastLog.TotalCost*1.1, usageRepo.lastLog.ActualCost, 1e-12)
+}
+
 func TestOpenAIGatewayServiceRecordUsage_Gpt54LongContextBillsWholeSession(t *testing.T) {
 	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
 	userRepo := &openAIRecordUsageUserRepoStub{}

backend/internal/service/openai_gateway_response_handling.go

@@ -756,10 +756,8 @@ func openAIUsageFromGJSON(value gjson.Result) (OpenAIUsage, bool) {
 	if outputTokens == 0 {
 		outputTokens = value.Get("completion_tokens").Int()
 	}
-	cacheReadTokens := value.Get("input_tokens_details.cached_tokens").Int()
-	if cacheReadTokens == 0 {
-		cacheReadTokens = value.Get("prompt_tokens_details.cached_tokens").Int()
-	}
+	cacheReadTokens := openAICacheReadTokensFromUsage(value)
+	cacheCreationTokens := openAICacheCreationTokensFromUsage(value)
 	imageOutputTokens := value.Get("output_tokens_details.image_tokens").Int()
 	if imageOutputTokens == 0 {
 		imageOutputTokens = value.Get("completion_tokens_details.image_tokens").Int()
@@ -767,12 +765,35 @@ func openAIUsageFromGJSON(value gjson.Result) (OpenAIUsage, bool) {
 	return OpenAIUsage{
 		InputTokens:              int(inputTokens),
 		OutputTokens:             int(outputTokens),
-		CacheCreationInputTokens: int(value.Get("cache_creation_input_tokens").Int()),
-		CacheReadInputTokens:     int(cacheReadTokens),
+		CacheCreationInputTokens: cacheCreationTokens,
+		CacheReadInputTokens:     cacheReadTokens,
 		ImageOutputTokens:        int(imageOutputTokens),
 	}, true
 }
 
+func openAICacheReadTokensFromUsage(value gjson.Result) int {
+	return firstPositiveGJSONInt(
+		value.Get("input_tokens_details.cached_tokens"),
+		value.Get("prompt_tokens_details.cached_tokens"),
+		value.Get("cache_read_input_tokens"),
+		value.Get("cache_read_tokens"),
+		value.Get("cached_tokens"),
+	)
+}
+
+func openAICacheCreationTokensFromUsage(value gjson.Result) int {
+	return firstPositiveGJSONInt(
+		value.Get("cache_creation_input_tokens"),
+		value.Get("cache_write_input_tokens"),
+		value.Get("cache_creation_tokens"),
+		value.Get("cache_write_tokens"),
+		value.Get("input_tokens_details.cache_creation_tokens"),
+		value.Get("input_tokens_details.cache_write_tokens"),
+		value.Get("prompt_tokens_details.cache_creation_tokens"),
+		value.Get("prompt_tokens_details.cache_write_tokens"),
+	)
+}
+
 func (s *OpenAIGatewayService) handleNonStreamingResponse(ctx context.Context, resp *http.Response, c *gin.Context, account *Account, originalModel, mappedModel string) (*openaiNonStreamingResult, error) {
 	body, err := ReadUpstreamResponseBody(resp.Body, s.cfg, c, openAITooLargeError)
 	if err != nil {

backend/internal/service/openai_gateway_service_test.go

@@ -2800,17 +2800,23 @@ func TestParseSSEUsage_SelectiveParsing(t *testing.T) {
 }
 
 func TestExtractOpenAIUsageFromJSONBytes_AcceptsResponseAndChatUsageShapes(t *testing.T) {
-	usage, ok := extractOpenAIUsageFromJSONBytes([]byte(`{"id":"resp_1","usage":{"input_tokens":3,"output_tokens":5,"input_tokens_details":{"cached_tokens":2}}}`))
+	usage, ok := extractOpenAIUsageFromJSONBytes([]byte(`{"id":"resp_1","usage":{"input_tokens":9,"output_tokens":5,"input_tokens_details":{"cached_tokens":2,"cache_write_tokens":4}}}`))
 	require.True(t, ok)
-	require.Equal(t, 3, usage.InputTokens)
+	require.Equal(t, 9, usage.InputTokens)
 	require.Equal(t, 5, usage.OutputTokens)
 	require.Equal(t, 2, usage.CacheReadInputTokens)
+	require.Equal(t, 4, usage.CacheCreationInputTokens)
 
-	usage, ok = extractOpenAIUsageFromJSONBytes([]byte(`{"type":"response.completed","response":{"usage":{"prompt_tokens":13,"completion_tokens":7,"prompt_tokens_details":{"cached_tokens":4}}}}`))
+	usage, ok = extractOpenAIUsageFromJSONBytes([]byte(`{"type":"response.completed","response":{"usage":{"prompt_tokens":13,"completion_tokens":7,"prompt_tokens_details":{"cached_tokens":4,"cache_creation_tokens":3}}}}`))
 	require.True(t, ok)
 	require.Equal(t, 13, usage.InputTokens)
 	require.Equal(t, 7, usage.OutputTokens)
 	require.Equal(t, 4, usage.CacheReadInputTokens)
+	require.Equal(t, 3, usage.CacheCreationInputTokens)
+
+	usage, ok = extractOpenAIUsageFromJSONBytes([]byte(`{"usage":{"input_tokens":11,"output_tokens":2,"cache_write_input_tokens":6}}`))
+	require.True(t, ok)
+	require.Equal(t, 6, usage.CacheCreationInputTokens)
 }
 
 func TestExtractCodexFinalResponse_SampleReplay(t *testing.T) {

backend/internal/service/openai_gateway_usage.go

@@ -119,9 +119,9 @@ func (s *OpenAIGatewayService) RecordUsage(ctx context.Context, input *OpenAIRec
 		ApplyOpenAIImageBillingResolution(result)
 	}
 
-	// 计算实际的新输入token（减去缓存读取的token）
-	// 因为 input_tokens 包含了 cache_read_tokens，而缓存读取的token不应按输入价格计费
-	actualInputTokens := result.Usage.InputTokens - result.Usage.CacheReadInputTokens
+	// OpenAI input_tokens 是总输入，包含缓存读取和缓存写入明细。
+	// 将三类 token 拆成互斥桶，避免缓存写入同时按普通输入和 cache_write 重复计费。
+	actualInputTokens := result.Usage.InputTokens - result.Usage.CacheReadInputTokens - result.Usage.CacheCreationInputTokens
 	if actualInputTokens < 0 {
 		actualInputTokens = 0
 	}

backend/internal/service/openai_ws_forwarder_support.go

@@ -262,15 +262,9 @@ func populateOpenAIUsageFromResponseJSON(body []byte, usage *OpenAIUsage) {
 	if usage == nil || len(body) == 0 {
 		return
 	}
-	values := gjson.GetManyBytes(
-		body,
-		"usage.input_tokens",
-		"usage.output_tokens",
-		"usage.input_tokens_details.cached_tokens",
-	)
-	usage.InputTokens = int(values[0].Int())
-	usage.OutputTokens = int(values[1].Int())
-	usage.CacheReadInputTokens = int(values[2].Int())
+	if parsed, ok := extractOpenAIUsageFromJSONBytes(body); ok {
+		*usage = parsed
+	}
 }
 
 func getOpenAIGroupIDFromContext(c *gin.Context) int64 {

backend/internal/service/openai_ws_v2/passthrough_relay.go

@@ -787,7 +787,7 @@ func parseUsageAndAccumulate(
 	parsedUsage := Usage{
 		InputTokens:              inputTokens,
 		OutputTokens:             outputTokens,
-		CacheCreationInputTokens: int(usageResult.Get("cache_creation_input_tokens").Int()),
+		CacheCreationInputTokens: openAICacheCreationTokensFromUsage(usageResult),
 		CacheReadInputTokens:     cachedTokens,
 		ImageOutputTokens:        int(imageTokens),
 	}
@@ -810,6 +810,24 @@ func parseUsageIntField(value gjson.Result, required bool) (int, bool) {
 	return int(value.Int()), true
 }
 
+func openAICacheCreationTokensFromUsage(value gjson.Result) int {
+	for _, field := range []string{
+		"cache_creation_input_tokens",
+		"cache_write_input_tokens",
+		"cache_creation_tokens",
+		"cache_write_tokens",
+		"input_tokens_details.cache_creation_tokens",
+		"input_tokens_details.cache_write_tokens",
+		"prompt_tokens_details.cache_creation_tokens",
+		"prompt_tokens_details.cache_write_tokens",
+	} {
+		if tokens := int(value.Get(field).Int()); tokens > 0 {
+			return tokens
+		}
+	}
+	return 0
+}
+
 func enrichResult(result *RelayResult, state *relayState, duration time.Duration) {
 	if result == nil {
 		return

backend/internal/service/openai_ws_v2/passthrough_relay_internal_test.go

@@ -300,7 +300,7 @@ func TestParseUsageAndEnrichCoverage(t *testing.T) {
 	require.Equal(t, 0, state.usage.OutputTokens)
 	require.Equal(t, 0, state.usage.CacheReadInputTokens)
 
-	parseUsageAndAccumulate(state, []byte(`{"type":"response.completed","response":{"usage":{"input_tokens":2,"output_tokens":1,"input_tokens_details":{"cached_tokens":1},"cache_creation_input_tokens":4,"output_tokens_details":{"image_tokens":3}}}}`), "response.completed", nil)
+	parseUsageAndAccumulate(state, []byte(`{"type":"response.completed","response":{"usage":{"input_tokens":2,"output_tokens":1,"input_tokens_details":{"cached_tokens":1,"cache_write_tokens":4},"output_tokens_details":{"image_tokens":3}}}}`), "response.completed", nil)
 	require.Equal(t, 2, state.usage.InputTokens)
 	require.Equal(t, 1, state.usage.OutputTokens)
 	require.Equal(t, 1, state.usage.CacheReadInputTokens)

backend/internal/service/pricing_service.go

@@ -61,6 +61,7 @@ type LiteLLMModelPricing struct {
 	OutputCostPerToken                  float64 `json:"output_cost_per_token"`
 	OutputCostPerTokenPriority          float64 `json:"output_cost_per_token_priority"`
 	CacheCreationInputTokenCost         float64 `json:"cache_creation_input_token_cost"`
+	CacheCreationInputTokenCostPriority float64 `json:"cache_creation_input_token_cost_priority"`
 	CacheCreationInputTokenCostAbove1hr float64 `json:"cache_creation_input_token_cost_above_1hr"`
 	CacheReadInputTokenCost             float64 `json:"cache_read_input_token_cost"`
 	CacheReadInputTokenCostPriority     float64 `json:"cache_read_input_token_cost_priority"`
@@ -93,6 +94,7 @@ type LiteLLMRawEntry struct {
 	OutputCostPerToken                  *float64 `json:"output_cost_per_token"`
 	OutputCostPerTokenPriority          *float64 `json:"output_cost_per_token_priority"`
 	CacheCreationInputTokenCost         *float64 `json:"cache_creation_input_token_cost"`
+	CacheCreationInputTokenCostPriority *float64 `json:"cache_creation_input_token_cost_priority"`
 	CacheCreationInputTokenCostAbove1hr *float64 `json:"cache_creation_input_token_cost_above_1hr"`
 	CacheReadInputTokenCost             *float64 `json:"cache_read_input_token_cost"`
 	CacheReadInputTokenCostPriority     *float64 `json:"cache_read_input_token_cost_priority"`
@@ -406,6 +408,9 @@ func (s *PricingService) parsePricingData(body []byte) (map[string]*LiteLLMModel
 		if entry.CacheCreationInputTokenCost != nil {
 			pricing.CacheCreationInputTokenCost = *entry.CacheCreationInputTokenCost
 		}
+		if entry.CacheCreationInputTokenCostPriority != nil {
+			pricing.CacheCreationInputTokenCostPriority = *entry.CacheCreationInputTokenCostPriority
+		}
 		if entry.CacheCreationInputTokenCostAbove1hr != nil {
 			pricing.CacheCreationInputTokenCostAbove1hr = *entry.CacheCreationInputTokenCostAbove1hr
 		}

backend/internal/service/pricing_service_test.go

@@ -19,6 +19,7 @@ func TestParsePricingData_ParsesPriorityAndServiceTierFields(t *testing.T) {
 			"output_cost_per_token": 0.000015,
 			"output_cost_per_token_priority": 0.00003,
 			"cache_creation_input_token_cost": 0.0000025,
+			"cache_creation_input_token_cost_priority": 0.000005,
 			"cache_read_input_token_cost": 0.00000025,
 			"cache_read_input_token_cost_priority": 0.0000005,
 			"supports_service_tier": true,
@@ -34,10 +35,66 @@ func TestParsePricingData_ParsesPriorityAndServiceTierFields(t *testing.T) {
 	require.NotNil(t, pricing)
 	require.InDelta(t, 5e-6, pricing.InputCostPerTokenPriority, 1e-12)
 	require.InDelta(t, 3e-5, pricing.OutputCostPerTokenPriority, 1e-12)
+	require.InDelta(t, 5e-6, pricing.CacheCreationInputTokenCostPriority, 1e-12)
 	require.InDelta(t, 5e-7, pricing.CacheReadInputTokenCostPriority, 1e-12)
 	require.True(t, pricing.SupportsServiceTier)
 }
 
+func TestBillingService_GPT56CacheWritePricingUsesInputTier(t *testing.T) {
+	for _, model := range []string{"gpt-5.6-sol", "gpt-5.6-terra", "gpt-5.6-luna"} {
+		t.Run(model, func(t *testing.T) {
+			pricingSvc := &PricingService{pricingData: map[string]*LiteLLMModelPricing{
+				model: {
+					InputCostPerToken:               5e-6,
+					InputCostPerTokenPriority:       10e-6,
+					OutputCostPerToken:              30e-6,
+					OutputCostPerTokenPriority:      60e-6,
+					CacheReadInputTokenCost:         0.5e-6,
+					CacheReadInputTokenCostPriority: 1e-6,
+				},
+			}}
+			svc := NewBillingService(&config.Config{}, pricingSvc)
+
+			pricing, err := svc.GetModelPricing(model)
+			require.NoError(t, err)
+			require.InDelta(t, 5e-6, pricing.CacheCreationPricePerToken, 1e-12)
+			require.InDelta(t, 10e-6, pricing.CacheCreationPricePerTokenPriority, 1e-12)
+
+			tokens := UsageTokens{InputTokens: 700, OutputTokens: 50, CacheCreationTokens: 200, CacheReadTokens: 100}
+			standard, err := svc.CalculateCostWithServiceTier(model, tokens, 1, "")
+			require.NoError(t, err)
+			require.InDelta(t, 200*5e-6, standard.CacheCreationCost, 1e-12)
+
+			priority, err := svc.CalculateCostWithServiceTier(model, tokens, 1, "priority")
+			require.NoError(t, err)
+			require.InDelta(t, 200*10e-6, priority.CacheCreationCost, 1e-12)
+
+			flex, err := svc.CalculateCostWithServiceTier(model, tokens, 1, "flex")
+			require.NoError(t, err)
+			require.InDelta(t, 200*2.5e-6, flex.CacheCreationCost, 1e-12)
+		})
+	}
+}
+
+func TestBillingService_GPT56CacheWriteContributesToLongContextThreshold(t *testing.T) {
+	model := "gpt-5.6-sol"
+	pricingSvc := &PricingService{pricingData: map[string]*LiteLLMModelPricing{
+		model: {
+			InputCostPerToken:       5e-6,
+			OutputCostPerToken:      30e-6,
+			CacheReadInputTokenCost: 0.5e-6,
+		},
+	}}
+	svc := NewBillingService(&config.Config{}, pricingSvc)
+	tokens := UsageTokens{InputTokens: 100000, CacheCreationTokens: 173000, OutputTokens: 10}
+
+	cost, err := svc.CalculateCost(model, tokens, 1)
+	require.NoError(t, err)
+	require.InDelta(t, 100000*10e-6, cost.InputCost, 1e-12)
+	require.InDelta(t, 173000*10e-6, cost.CacheCreationCost, 1e-12)
+	require.InDelta(t, 10*45e-6, cost.OutputCost, 1e-12)
+}
+
 func TestParsePricingData_KeepsImageOnlyPricing(t *testing.T) {
 	svc := &PricingService{}
 	body := []byte(`{