feat: bill OpenAI cache_write_tokens at cache-creation price with zero clamp

Parse OpenAI's native cache_write_tokens (chat prompt_tokens_details /
responses input_tokens_details), bill it at the cache-creation ratio, and
clamp the uncached prompt remainder at zero since cached + cache-write can
exceed prompt_tokens. Propagate the field through chat/responses/claude
format conversions and tiered expression billing (cc variable).

dto/billing_usage.go

@@ -88,6 +88,7 @@ func HasOpenAIUsageTokens(usage *Usage) bool {
 	}
 	if usage.PromptTokensDetails.CachedTokens != 0 ||
 		usage.PromptTokensDetails.CachedCreationTokens != 0 ||
+		usage.PromptTokensDetails.CacheWriteTokens != 0 ||
 		usage.PromptTokensDetails.TextTokens != 0 ||
 		usage.PromptTokensDetails.ImageTokens != 0 ||
 		usage.PromptTokensDetails.AudioTokens != 0 {

dto/openai_request.go

@@ -849,6 +849,7 @@ type OpenAIResponsesRequest struct {
 	MaxOutputTokens    *uint           `json:"max_output_tokens,omitempty"`
 	TopLogProbs        *int            `json:"top_logprobs,omitempty"`
 	Metadata           json.RawMessage `json:"metadata,omitempty"`
+	Moderation         json.RawMessage `json:"moderation,omitempty"`
 	ParallelToolCalls  json.RawMessage `json:"parallel_tool_calls,omitempty"`
 	PreviousResponseID string          `json:"previous_response_id,omitempty"`
 	Reasoning          *Reasoning      `json:"reasoning,omitempty"`
@@ -859,6 +860,7 @@ type OpenAIResponsesRequest struct {
 	// This field is allowed by default and can be disabled via channel setting disable_store.
 	Store                json.RawMessage `json:"store,omitempty"`
 	PromptCacheKey       json.RawMessage `json:"prompt_cache_key,omitempty"`
+	PromptCacheOptions   json.RawMessage `json:"prompt_cache_options,omitempty"`
 	PromptCacheRetention json.RawMessage `json:"prompt_cache_retention,omitempty"`
 	// SafetyIdentifier carries client identity for policy abuse detection.
 	// This field is filtered by default and can be enabled via channel setting allow_safety_identifier.

dto/openai_response.go

@@ -256,9 +256,26 @@ type OpenAIVideoResponse struct {
 type InputTokenDetails struct {
 	CachedTokens         int `json:"cached_tokens"`
 	CachedCreationTokens int `json:"cached_creation_tokens,omitempty"`
-	TextTokens           int `json:"text_tokens"`
+	// CacheWriteTokens is OpenAI's native cache-write count, reported as
-	AudioTokens          int `json:"audio_tokens"`
+	// prompt_tokens_details.cache_write_tokens (Chat Completions) or
-	ImageTokens          int `json:"image_tokens"`
+	// input_tokens_details.cache_write_tokens (Responses). It is billed at the
+	// cache-creation price.
+	CacheWriteTokens int `json:"cache_write_tokens,omitempty"`
+	TextTokens       int `json:"text_tokens"`
+	AudioTokens      int `json:"audio_tokens"`
+	ImageTokens      int `json:"image_tokens"`
+}
+
+// CacheCreationTokensTotal returns the cache-write token count regardless of
+// which field the upstream reported it in: Claude-derived conversions populate
+// CachedCreationTokens while OpenAI reports cache_write_tokens natively. Both
+// are billed at the cache-creation price; when both are present the larger
+// value wins so the same tokens are never double-counted.
+func (d InputTokenDetails) CacheCreationTokensTotal() int {
+	if d.CacheWriteTokens > d.CachedCreationTokens {
+		return d.CacheWriteTokens
+	}
+	return d.CachedCreationTokens
 }
 
 type OutputTokenDetails struct {

dto/openai_responses_compaction_request.go

@@ -17,12 +17,14 @@ type OpenAIResponsesCompactionRequest struct {
 	// Codex compact request parity:
 	// https://github.com/openai/codex/commit/53d59722268dde82fb93c1f37964ce196c2a86d7
 	// https://github.com/openai/codex/commit/5d6f23a27bf9c90709af527a7108c1c2eadf5123
-	Tools             json.RawMessage `json:"tools,omitempty"`
+	Tools                json.RawMessage `json:"tools,omitempty"`
-	ParallelToolCalls json.RawMessage `json:"parallel_tool_calls,omitempty"`
+	ParallelToolCalls    json.RawMessage `json:"parallel_tool_calls,omitempty"`
-	Reasoning         *Reasoning      `json:"reasoning,omitempty"`
+	Reasoning            *Reasoning      `json:"reasoning,omitempty"`
-	ServiceTier       string          `json:"service_tier,omitempty"`
+	ServiceTier          string          `json:"service_tier,omitempty"`
-	PromptCacheKey    json.RawMessage `json:"prompt_cache_key,omitempty"`
+	PromptCacheKey       json.RawMessage `json:"prompt_cache_key,omitempty"`
-	Text              json.RawMessage `json:"text,omitempty"`
+	PromptCacheOptions   json.RawMessage `json:"prompt_cache_options,omitempty"`
+	PromptCacheRetention json.RawMessage `json:"prompt_cache_retention,omitempty"`
+	Text                 json.RawMessage `json:"text,omitempty"`
 }
 
 func (r *OpenAIResponsesCompactionRequest) GetTokenCountMeta() *types.TokenCountMeta {

relay/channel/openai/relay_responses.go

@@ -51,6 +51,7 @@ func OaiResponsesHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http
 		usage.TotalTokens = responsesResponse.Usage.TotalTokens
 		if responsesResponse.Usage.InputTokensDetails != nil {
 			usage.PromptTokensDetails.CachedTokens = responsesResponse.Usage.InputTokensDetails.CachedTokens
+			usage.PromptTokensDetails.CacheWriteTokens = responsesResponse.Usage.InputTokensDetails.CacheWriteTokens
 		}
 	}
 	if info == nil || info.ResponsesUsageInfo == nil || info.ResponsesUsageInfo.BuiltInTools == nil {
@@ -104,6 +105,7 @@ func OaiResponsesStreamHandler(c *gin.Context, info *relaycommon.RelayInfo, resp
 					}
 					if streamResponse.Response.Usage.InputTokensDetails != nil {
 						usage.PromptTokensDetails.CachedTokens = streamResponse.Response.Usage.InputTokensDetails.CachedTokens
+						usage.PromptTokensDetails.CacheWriteTokens = streamResponse.Response.Usage.InputTokensDetails.CacheWriteTokens
 					}
 				}
 				if streamResponse.Response.HasImageGenerationCall() {

relay/channel/openai/relay_responses_compact.go

@@ -37,6 +37,7 @@ func OaiResponsesCompactionHandler(c *gin.Context, resp *http.Response) (*dto.Us
 		usage.TotalTokens = compactResp.Usage.TotalTokens
 		if compactResp.Usage.InputTokensDetails != nil {
 			usage.PromptTokensDetails.CachedTokens = compactResp.Usage.InputTokensDetails.CachedTokens
+			usage.PromptTokensDetails.CacheWriteTokens = compactResp.Usage.InputTokensDetails.CacheWriteTokens
 		}
 	}
 

relay/responses_handler.go

@@ -41,12 +41,14 @@ func ResponsesHelper(c *gin.Context, info *relaycommon.RelayInfo) (newAPIError *
 		responsesReq = req
 	case *dto.OpenAIResponsesCompactionRequest:
 		responsesReq = &dto.OpenAIResponsesRequest{
-			Model:              req.Model,
+			Model:                req.Model,
-			Input:              req.Input,
+			Input:                req.Input,
-			Instructions:       req.Instructions,
+			Instructions:         req.Instructions,
-			PreviousResponseID: req.PreviousResponseID,
+			PreviousResponseID:   req.PreviousResponseID,
-			ParallelToolCalls:  req.ParallelToolCalls,
+			ParallelToolCalls:    req.ParallelToolCalls,
-			ServiceTier:        req.ServiceTier,
+			ServiceTier:          req.ServiceTier,
+			PromptCacheOptions:   req.PromptCacheOptions,
+			PromptCacheRetention: req.PromptCacheRetention,
 		}
 	default:
 		return types.NewErrorWithStatusCode(

service/relayconvert/internal/claude_messages/to_oai_chat_resp.go

@@ -216,6 +216,9 @@ func buildOpenAIStyleUsageFromClaudeUsage(usage *dto.Usage) dto.Usage {
 		usage.ClaudeCacheCreation1hTokens,
 	)
 	cacheCreationTokens := cacheCreationTokensForOpenAIUsage(usage)
+	// Expose the standard OpenAI cache-write field alongside the legacy
+	// cached_creation_tokens so OpenAI-format clients can bill cache writes.
+	clone.PromptTokensDetails.CacheWriteTokens = cacheCreationTokens
 	totalInputTokens := usage.PromptTokens + usage.PromptTokensDetails.CachedTokens + cacheCreationTokens
 	clone.PromptTokens = totalInputTokens
 	clone.InputTokens = totalInputTokens

service/relayconvert/internal/oai_chat/to_claude_messages_resp.go

@@ -39,10 +39,21 @@ func buildClaudeUsageFromOpenAIUsage(oaiUsage *dto.Usage) *dto.ClaudeUsage {
 		oaiUsage.ClaudeCacheCreation5mTokens,
 		oaiUsage.ClaudeCacheCreation1hTokens,
 	)
+	cacheCreationTokens := oaiUsage.PromptTokensDetails.CacheCreationTokensTotal()
+	inputTokens := oaiUsage.PromptTokens
+	if oaiUsage.PromptTokensDetails.CacheWriteTokens > 0 {
+		// OpenAI native cache-write usage counts cached and cache-write tokens
+		// inside prompt_tokens, while Claude semantics reports input_tokens
+		// excluding both; the uncached remainder clamps at zero.
+		inputTokens = oaiUsage.PromptTokens - oaiUsage.PromptTokensDetails.CachedTokens - cacheCreationTokens
+		if inputTokens < 0 {
+			inputTokens = 0
+		}
+	}
 	usage := &dto.ClaudeUsage{
-		InputTokens:              oaiUsage.PromptTokens,
+		InputTokens:              inputTokens,
 		OutputTokens:             oaiUsage.CompletionTokens,
-		CacheCreationInputTokens: oaiUsage.PromptTokensDetails.CachedCreationTokens,
+		CacheCreationInputTokens: cacheCreationTokens,
 		CacheReadInputTokens:     oaiUsage.PromptTokensDetails.CachedTokens,
 		BillingUsage:             billingUsage,
 	}

service/relayconvert/internal/oai_chat/to_claude_messages_resp_test.go

@@ -79,6 +79,30 @@ func TestResponseOpenAI2ClaudeUsageCarriesOpenAIBillingUsage(t *testing.T) {
 	assert.Nil(t, resp.Usage.BillingUsage.OpenAIUsage.BillingUsage)
 }
 
+func TestBuildClaudeUsageFromOpenAICacheWriteUsage(t *testing.T) {
+	usage := buildClaudeUsageFromOpenAIUsage(&dto.Usage{
+		PromptTokens:     3619,
+		CompletionTokens: 36,
+		TotalTokens:      3655,
+		PromptTokensDetails: dto.InputTokenDetails{
+			CachedTokens:     2921,
+			CacheWriteTokens: 3616,
+		},
+	})
+
+	require.NotNil(t, usage)
+	// Claude semantics reports input_tokens excluding cache read/write; the
+	// remainder 3619-2921-3616 clamps to 0.
+	assert.Equal(t, 0, usage.InputTokens)
+	assert.Equal(t, 2921, usage.CacheReadInputTokens)
+	assert.Equal(t, 3616, usage.CacheCreationInputTokens)
+	assert.Equal(t, 36, usage.OutputTokens)
+	require.NotNil(t, usage.BillingUsage)
+	require.NotNil(t, usage.BillingUsage.OpenAIUsage)
+	assert.Equal(t, dto.BillingUsageSemanticOpenAI, usage.BillingUsage.Semantic)
+	assert.Equal(t, 3616, usage.BillingUsage.OpenAIUsage.PromptTokensDetails.CacheWriteTokens)
+}
+
 func TestStreamResponseOpenAI2ClaudeClosesTextThinkingAndToolBlocks(t *testing.T) {
 	info := &relaycommon.RelayInfo{
 		ClaudeConvertInfo: &relaycommon.ClaudeConvertInfo{

service/relayconvert/internal/oai_chat/to_oai_responses_resp.go

@@ -137,6 +137,7 @@ func UsageFromChatUsage(src *dto.Usage) *dto.Usage {
 		src.PromptTokensDetails.ImageTokens != 0 ||
 		src.PromptTokensDetails.AudioTokens != 0 ||
 		src.PromptTokensDetails.CachedCreationTokens != 0 ||
+		src.PromptTokensDetails.CacheWriteTokens != 0 ||
 		src.PromptTokensDetails.TextTokens != 0 {
 		details := src.PromptTokensDetails
 		usage.InputTokensDetails = &details

service/relayconvert/internal/oai_responses/to_oai_chat_resp.go

@@ -156,6 +156,7 @@ func UsageFromResponsesUsage(src *dto.Usage) *dto.Usage {
 	if src.InputTokensDetails != nil {
 		usage.PromptTokensDetails.CachedTokens = src.InputTokensDetails.CachedTokens
 		usage.PromptTokensDetails.CachedCreationTokens = src.InputTokensDetails.CachedCreationTokens
+		usage.PromptTokensDetails.CacheWriteTokens = src.InputTokensDetails.CacheWriteTokens
 		usage.PromptTokensDetails.TextTokens = src.InputTokensDetails.TextTokens
 		usage.PromptTokensDetails.ImageTokens = src.InputTokensDetails.ImageTokens
 		usage.PromptTokensDetails.AudioTokens = src.InputTokensDetails.AudioTokens

service/relayconvert/response_registry_test.go

@@ -277,6 +277,7 @@ func TestConvertResponseProviderToOAIChatUsage(t *testing.T) {
 	assert.Equal(t, 22, toChat.Usage.TotalTokens)
 	assert.Equal(t, 3, toChat.Usage.PromptTokensDetails.CachedTokens)
 	assert.Equal(t, 4, toChat.Usage.PromptTokensDetails.CachedCreationTokens)
+	assert.Equal(t, 4, toChat.Usage.PromptTokensDetails.CacheWriteTokens)
 	require.NotNil(t, toChat.Usage.BillingUsage)
 	require.NotNil(t, toChat.Usage.BillingUsage.ClaudeUsage)
 	assert.Equal(t, dto.BillingUsageSourceClaudeMessages, toChat.Usage.BillingUsage.Source)
@@ -539,6 +540,7 @@ func TestResponseUsageMatrixChatAndResponsesDetails(t *testing.T) {
 		PromptTokensDetails: dto.InputTokenDetails{
 			CachedTokens:         3,
 			CachedCreationTokens: 2,
+			CacheWriteTokens:     6,
 			TextTokens:           4,
 			AudioTokens:          1,
 			ImageTokens:          5,
@@ -558,6 +560,7 @@ func TestResponseUsageMatrixChatAndResponsesDetails(t *testing.T) {
 	require.NotNil(t, result.Usage.InputTokensDetails)
 	assert.Equal(t, 3, result.Usage.InputTokensDetails.CachedTokens)
 	assert.Equal(t, 2, result.Usage.InputTokensDetails.CachedCreationTokens)
+	assert.Equal(t, 6, result.Usage.InputTokensDetails.CacheWriteTokens)
 	assert.Equal(t, 4, result.Usage.InputTokensDetails.TextTokens)
 	assert.Equal(t, 1, result.Usage.InputTokensDetails.AudioTokens)
 	assert.Equal(t, 5, result.Usage.InputTokensDetails.ImageTokens)
@@ -579,6 +582,7 @@ func TestResponseUsageMatrixChatAndResponsesDetails(t *testing.T) {
 			InputTokensDetails: &dto.InputTokenDetails{
 				CachedTokens:         4,
 				CachedCreationTokens: 1,
+				CacheWriteTokens:     7,
 				TextTokens:           5,
 				AudioTokens:          2,
 				ImageTokens:          1,
@@ -598,6 +602,7 @@ func TestResponseUsageMatrixChatAndResponsesDetails(t *testing.T) {
 	assert.Equal(t, 21, result.Usage.TotalTokens)
 	assert.Equal(t, 4, result.Usage.PromptTokensDetails.CachedTokens)
 	assert.Equal(t, 1, result.Usage.PromptTokensDetails.CachedCreationTokens)
+	assert.Equal(t, 7, result.Usage.PromptTokensDetails.CacheWriteTokens)
 	assert.Equal(t, 5, result.Usage.PromptTokensDetails.TextTokens)
 	assert.Equal(t, 2, result.Usage.PromptTokensDetails.AudioTokens)
 	assert.Equal(t, 1, result.Usage.PromptTokensDetails.ImageTokens)

service/text_quota.go

@@ -208,7 +208,7 @@ func calculateTextQuotaSummary(ctx *gin.Context, relayInfo *relaycommon.RelayInf
 	summary.CompletionTokens = usage.CompletionTokens
 	summary.TotalTokens = usage.PromptTokens + usage.CompletionTokens
 	summary.CacheTokens = usage.PromptTokensDetails.CachedTokens
-	summary.CacheCreationTokens = usage.PromptTokensDetails.CachedCreationTokens
+	summary.CacheCreationTokens = usage.PromptTokensDetails.CacheCreationTokensTotal()
 	summary.CacheCreationTokens5m = usage.ClaudeCacheCreation5mTokens
 	summary.CacheCreationTokens1h = usage.ClaudeCacheCreation1hTokens
 	summary.ImageTokens = usage.PromptTokensDetails.ImageTokens
@@ -294,6 +294,13 @@ func calculateTextQuotaSummary(ctx *gin.Context, relayInfo *relaycommon.RelayInf
 			}
 		}
 
+		// OpenAI cache-write usage can report cached_tokens + cache_write_tokens
+		// exceeding prompt_tokens; the uncached remainder must clamp at zero so
+		// billing never subtracts more than the reported input.
+		if baseTokens.IsNegative() {
+			baseTokens = decimal.Zero
+		}
+
 		promptQuota := baseTokens.Add(cachedTokensWithRatio).Add(imageTokensWithRatio).Add(cachedCreationTokensWithRatio)
 		completionQuota := dCompletionTokens.Mul(dCompletionRatio)
 		quotaCalculateDecimal := promptQuota.Add(completionQuota).Mul(ratio)

service/text_quota_test.go

@@ -375,6 +375,62 @@ func TestCalculateTextQuotaSummaryHandlesLegacyClaudeDerivedOpenAIUsage(t *testi
 	require.Equal(t, 1624, summary.Quota)
 }
 
+func TestCalculateTextQuotaSummaryBillsOpenAICacheWriteTokens(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	w := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(w)
+
+	relayInfo := &relaycommon.RelayInfo{
+		RelayFormat:     types.RelayFormatOpenAI,
+		OriginModelName: "gpt-5.1",
+		PriceData: types.PriceData{
+			ModelRatio:         1,
+			CompletionRatio:    2,
+			CacheRatio:         0.1,
+			CacheCreationRatio: 1.25,
+			GroupRatioInfo:     types.GroupRatioInfo{GroupRatio: 1},
+		},
+		StartTime: time.Now(),
+	}
+
+	t.Run("uncached remainder stays positive", func(t *testing.T) {
+		usage := &dto.Usage{
+			PromptTokens:     1473,
+			CompletionTokens: 19,
+			PromptTokensDetails: dto.InputTokenDetails{
+				CacheWriteTokens: 1470,
+			},
+		}
+
+		summary := calculateTextQuotaSummary(ctx, relayInfo, usage)
+
+		require.Equal(t, 1470, summary.CacheCreationTokens)
+		// (1473-0-1470) + 1470*1.25 + 19*2 = 3 + 1837.5 + 38 = 1878.5 => 1879
+		require.Equal(t, 1879, summary.Quota)
+	})
+
+	t.Run("uncached remainder clamps to zero", func(t *testing.T) {
+		// Real OpenAI payload shape: cached_tokens + cache_write_tokens exceeds
+		// prompt_tokens, so the uncached remainder must clamp to 0 instead of
+		// producing a negative charge component.
+		usage := &dto.Usage{
+			PromptTokens:     3619,
+			CompletionTokens: 36,
+			PromptTokensDetails: dto.InputTokenDetails{
+				CachedTokens:     2921,
+				CacheWriteTokens: 3616,
+			},
+		}
+
+		summary := calculateTextQuotaSummary(ctx, relayInfo, usage)
+
+		require.Equal(t, 3619, summary.PromptTokens)
+		require.Equal(t, 3616, summary.CacheCreationTokens)
+		// max(3619-2921-3616, 0) + 2921*0.1 + 3616*1.25 + 36*2 = 4884.1 => 4884
+		require.Equal(t, 4884, summary.Quota)
+	})
+}
+
 func TestCalculateTextQuotaSummarySeparatesOpenRouterCacheReadFromPromptBilling(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	w := httptest.NewRecorder()

service/tiered_settle.go

@@ -22,7 +22,7 @@ func BuildTieredTokenParams(usage *dto.Usage, isClaudeUsageSemantic bool, usedVa
 	p := float64(usage.PromptTokens)
 	c := float64(usage.CompletionTokens)
 	cr := float64(usage.PromptTokensDetails.CachedTokens)
-	cc5m := float64(usage.PromptTokensDetails.CachedCreationTokens)
+	cc5m := float64(usage.PromptTokensDetails.CacheCreationTokensTotal())
 	cc1h := float64(0)
 
 	if usage.UsageSemantic == "anthropic" {

setting/ratio_setting/cache_ratio.go

@@ -81,6 +81,9 @@ var defaultCacheRatio = map[string]float64{
 }
 
 var defaultCreateCacheRatio = map[string]float64{
+	"gpt-5.6-sol":                         1.25,
+	"gpt-5.6-terra":                       1.25,
+	"gpt-5.6-luna":                        1.25,
 	"claude-3-sonnet-20240229":            1.25,
 	"claude-3-opus-20240229":              1.25,
 	"claude-3-haiku-20240307":             1.25,

web/default/src/features/usage-logs/components/usage-logs-mobile-card.tsx

@@ -329,7 +329,7 @@ function CommonLogsCard<TData>({
         />
       </div>
 
-      <div className='grid grid-cols-[minmax(0,1.35fr)_minmax(0,0.75fr)] gap-1.5'>
+      <div className='grid grid-cols-[minmax(0,1fr)_minmax(0,0.8fr)] gap-1.5'>
         <div className='bg-muted/20 min-w-0 rounded-md px-2 py-1.5'>
           <MobileLogTimeStatus
             createdAt={rowData?.created_at}