server: add cached eval metric to response

Added cached prompt token counts to Ollama responses and compatibility usage fields.

This carries local `llama-server` `cache_n` and MLX cache hits through `/api/generate`, `/api/chat`, OpenAI-compatible endpoints, and Anthropic-compatible `/v1/messages`. Cloud responses are passed through as-is, so cache counts will show up there once Cloud starts returning them.

anthropic/anthropic.go

@@ -217,8 +217,30 @@ type MessagesResponse struct {
 
 // Usage contains token usage information
 type Usage struct {
-	InputTokens  int `json:"input_tokens"`
+	InputTokens              int `json:"input_tokens"`
-	OutputTokens int `json:"output_tokens"`
+	CacheCreationInputTokens int `json:"cache_creation_input_tokens"`
+	CacheReadInputTokens     int `json:"cache_read_input_tokens"`
+	OutputTokens             int `json:"output_tokens"`
+}
+
+func UsageFromMetrics(metrics api.Metrics) Usage {
+	cached := metrics.PromptEvalCachedCount
+	if cached > metrics.PromptEvalCount {
+		cached = metrics.PromptEvalCount
+	}
+
+	return Usage{
+		InputTokens:          metrics.PromptEvalCount - cached,
+		CacheReadInputTokens: cached,
+		OutputTokens:         metrics.EvalCount,
+	}
+}
+
+func (u *Usage) Add(other Usage) {
+	u.InputTokens += other.InputTokens
+	u.CacheCreationInputTokens += other.CacheCreationInputTokens
+	u.CacheReadInputTokens += other.CacheReadInputTokens
+	u.OutputTokens += other.OutputTokens
 }
 
 // Streaming event types
@@ -273,8 +295,10 @@ type MessageDelta struct {
 
 // DeltaUsage contains cumulative token usage
 type DeltaUsage struct {
-	InputTokens  int `json:"input_tokens"`
+	InputTokens              int `json:"input_tokens"`
-	OutputTokens int `json:"output_tokens"`
+	CacheCreationInputTokens int `json:"cache_creation_input_tokens"`
+	CacheReadInputTokens     int `json:"cache_read_input_tokens"`
+	OutputTokens             int `json:"output_tokens"`
 }
 
 // MessageStopEvent signals the end of the message
@@ -688,10 +712,7 @@ func ToMessagesResponse(id string, r api.ChatResponse) MessagesResponse {
 		Model:      r.Model,
 		Content:    content,
 		StopReason: stopReason,
-		Usage: Usage{
+		Usage:      UsageFromMetrics(r.Metrics),
-			InputTokens:  r.Metrics.PromptEvalCount,
-			OutputTokens: r.Metrics.EvalCount,
-		},
 	}
 }
 
@@ -721,6 +742,8 @@ type StreamConverter struct {
 	firstWrite           bool
 	contentIndex         int
 	inputTokens          int
+	cacheCreationTokens  int
+	cacheReadTokens      int
 	outputTokens         int
 	estimatedInputTokens int // Estimated tokens from request (used when actual metrics are 0)
 	thinkingStarted      bool
@@ -753,7 +776,12 @@ func (c *StreamConverter) Process(r api.ChatResponse) []StreamEvent {
 		c.firstWrite = false
 		// Use actual metrics if available, otherwise use estimate
 		c.inputTokens = r.Metrics.PromptEvalCount
-		if c.inputTokens == 0 && c.estimatedInputTokens > 0 {
+		c.cacheReadTokens = r.Metrics.PromptEvalCachedCount
+		if c.cacheReadTokens > c.inputTokens {
+			c.cacheReadTokens = c.inputTokens
+		}
+		c.inputTokens -= c.cacheReadTokens
+		if c.inputTokens == 0 && c.cacheReadTokens == 0 && c.estimatedInputTokens > 0 {
 			c.inputTokens = c.estimatedInputTokens
 		}
 
@@ -768,8 +796,10 @@ func (c *StreamConverter) Process(r api.ChatResponse) []StreamEvent {
 					Model:   c.Model,
 					Content: []ContentBlock{},
 					Usage: Usage{
-						InputTokens:  c.inputTokens,
+						InputTokens:              c.inputTokens,
-						OutputTokens: 0,
+						CacheCreationInputTokens: c.cacheCreationTokens,
+						CacheReadInputTokens:     c.cacheReadTokens,
+						OutputTokens:             0,
 					},
 				},
 			},
@@ -939,6 +969,11 @@ func (c *StreamConverter) Process(r api.ChatResponse) []StreamEvent {
 		}
 
 		c.inputTokens = r.Metrics.PromptEvalCount
+		c.cacheReadTokens = r.Metrics.PromptEvalCachedCount
+		if c.cacheReadTokens > c.inputTokens {
+			c.cacheReadTokens = c.inputTokens
+		}
+		c.inputTokens -= c.cacheReadTokens
 		c.outputTokens = r.Metrics.EvalCount
 		stopReason := mapStopReason(r.DoneReason, len(c.toolCallsSent) > 0)
 
@@ -950,8 +985,10 @@ func (c *StreamConverter) Process(r api.ChatResponse) []StreamEvent {
 					StopReason: stopReason,
 				},
 				Usage: DeltaUsage{
-					InputTokens:  c.inputTokens,
+					InputTokens:              c.inputTokens,
-					OutputTokens: c.outputTokens,
+					CacheCreationInputTokens: c.cacheCreationTokens,
+					CacheReadInputTokens:     c.cacheReadTokens,
+					OutputTokens:             c.outputTokens,
 				},
 			},
 		})

anthropic/anthropic_test.go

@@ -778,6 +778,38 @@ func TestToMessagesResponse_Basic(t *testing.T) {
 	}
 }
 
+func TestToMessagesResponse_UsageIncludesCacheReadTokens(t *testing.T) {
+	resp := api.ChatResponse{
+		Model: "test-model",
+		Message: api.Message{
+			Role:    "assistant",
+			Content: "Hello there!",
+		},
+		Done:       true,
+		DoneReason: "stop",
+		Metrics: api.Metrics{
+			PromptEvalCount:       10,
+			PromptEvalCachedCount: 4,
+			EvalCount:             5,
+		},
+	}
+
+	result := ToMessagesResponse("msg_123", resp)
+
+	if result.Usage.InputTokens != 6 {
+		t.Errorf("expected input_tokens 6, got %d", result.Usage.InputTokens)
+	}
+	if result.Usage.CacheReadInputTokens != 4 {
+		t.Errorf("expected cache_read_input_tokens 4, got %d", result.Usage.CacheReadInputTokens)
+	}
+	if result.Usage.CacheCreationInputTokens != 0 {
+		t.Errorf("expected cache_creation_input_tokens 0, got %d", result.Usage.CacheCreationInputTokens)
+	}
+	if result.Usage.OutputTokens != 5 {
+		t.Errorf("expected output_tokens 5, got %d", result.Usage.OutputTokens)
+	}
+}
+
 func TestToMessagesResponse_WithToolCalls(t *testing.T) {
 	resp := api.ChatResponse{
 		Model: "test-model",
@@ -988,6 +1020,51 @@ func TestStreamConverter_Basic(t *testing.T) {
 	}
 }
 
+func TestStreamConverter_UsageIncludesCacheReadTokens(t *testing.T) {
+	conv := NewStreamConverter("msg_123", "test-model", 0)
+
+	events := conv.Process(api.ChatResponse{
+		Model:      "test-model",
+		Message:    api.Message{Role: "assistant"},
+		Done:       true,
+		DoneReason: "stop",
+		Metrics: api.Metrics{
+			PromptEvalCount:       10,
+			PromptEvalCachedCount: 4,
+			EvalCount:             5,
+		},
+	})
+
+	var found bool
+	for _, e := range events {
+		if e.Event != "message_delta" {
+			continue
+		}
+
+		data, ok := e.Data.(MessageDeltaEvent)
+		if !ok {
+			t.Fatalf("unexpected data type: %T", e.Data)
+		}
+		found = true
+		if data.Usage.InputTokens != 6 {
+			t.Errorf("expected input_tokens 6, got %d", data.Usage.InputTokens)
+		}
+		if data.Usage.CacheReadInputTokens != 4 {
+			t.Errorf("expected cache_read_input_tokens 4, got %d", data.Usage.CacheReadInputTokens)
+		}
+		if data.Usage.CacheCreationInputTokens != 0 {
+			t.Errorf("expected cache_creation_input_tokens 0, got %d", data.Usage.CacheCreationInputTokens)
+		}
+		if data.Usage.OutputTokens != 5 {
+			t.Errorf("expected output_tokens 5, got %d", data.Usage.OutputTokens)
+		}
+	}
+
+	if !found {
+		t.Fatal("expected message_delta event")
+	}
+}
+
 func TestStreamConverter_WithToolCalls(t *testing.T) {
 	conv := NewStreamConverter("msg_123", "test-model", 0)
 

api/types.go

@@ -569,12 +569,13 @@ type DebugInfo struct {
 }
 
 type Metrics struct {
-	TotalDuration      time.Duration `json:"total_duration,omitempty"`
+	TotalDuration         time.Duration `json:"total_duration,omitempty"`
-	LoadDuration       time.Duration `json:"load_duration,omitempty"`
+	LoadDuration          time.Duration `json:"load_duration,omitempty"`
-	PromptEvalCount    int           `json:"prompt_eval_count,omitempty"`
+	PromptEvalCount       int           `json:"prompt_eval_count,omitempty"`
-	PromptEvalDuration time.Duration `json:"prompt_eval_duration,omitempty"`
+	PromptEvalCachedCount int           `json:"prompt_eval_cached_count,omitempty"`
-	EvalCount          int           `json:"eval_count,omitempty"`
+	PromptEvalDuration    time.Duration `json:"prompt_eval_duration,omitempty"`
-	EvalDuration       time.Duration `json:"eval_duration,omitempty"`
+	EvalCount             int           `json:"eval_count,omitempty"`
+	EvalDuration          time.Duration `json:"eval_duration,omitempty"`
 }
 
 // Options specified in [GenerateRequest].  If you add a new option here, also
@@ -968,6 +969,10 @@ func (m *Metrics) Summary() {
 		fmt.Fprintf(os.Stderr, "prompt eval count:    %d token(s)\n", m.PromptEvalCount)
 	}
 
+	if m.PromptEvalCachedCount > 0 {
+		fmt.Fprintf(os.Stderr, "prompt eval cached:   %d token(s)\n", m.PromptEvalCachedCount)
+	}
+
 	if m.PromptEvalDuration > 0 {
 		fmt.Fprintf(os.Stderr, "prompt eval duration: %s\n", m.PromptEvalDuration)
 		fmt.Fprintf(os.Stderr, "prompt eval rate:     %.2f tokens/s\n", float64(m.PromptEvalCount)/m.PromptEvalDuration.Seconds())

docs/api.md

@@ -110,6 +110,7 @@ The final response in the stream also includes additional data about the generat
 - `total_duration`: time spent generating the response
 - `load_duration`: time spent in nanoseconds loading the model
 - `prompt_eval_count`: number of tokens in the prompt
+- `prompt_eval_cached_count`: number of prompt tokens read from the prompt cache, when available
 - `prompt_eval_duration`: time spent in nanoseconds evaluating the prompt
 - `eval_count`: number of tokens in the response
 - `eval_duration`: time in nanoseconds spent generating the response

docs/api/usage.mdx

@@ -7,6 +7,7 @@ Ollama's API responses include metrics that can be used for measuring performanc
 * `total_duration`: How long the response took to generate
 * `load_duration`: How long the model took to load
 * `prompt_eval_count`: How many input tokens were processed
+* `prompt_eval_cached_count`: How many input tokens were read from the prompt cache, when available
 * `prompt_eval_duration`: How long it took to evaluate the prompt
 * `eval_count`: How many output tokens were processes
 * `eval_duration`: How long it took to generate the output tokens

docs/openapi.yaml

@@ -147,6 +147,9 @@ components:
         prompt_eval_count:
           type: integer
           description: Number of input tokens in the prompt
+        prompt_eval_cached_count:
+          type: integer
+          description: Number of input tokens read from the prompt cache
         prompt_eval_duration:
           type: integer
           description: Time spent evaluating the prompt in nanoseconds
@@ -191,6 +194,9 @@ components:
         prompt_eval_count:
           type: integer
           description: Number of input tokens in the prompt
+        prompt_eval_cached_count:
+          type: integer
+          description: Number of input tokens read from the prompt cache
         prompt_eval_duration:
           type: integer
           description: Time spent evaluating the prompt in nanoseconds
@@ -352,6 +358,9 @@ components:
         prompt_eval_count:
           type: integer
           description: Number of tokens in the prompt
+        prompt_eval_cached_count:
+          type: integer
+          description: Number of prompt tokens read from the prompt cache
         prompt_eval_duration:
           type: integer
           description: Time spent evaluating the prompt in nanoseconds

llm/llama_server.go

@@ -1625,13 +1625,14 @@ func (s *llamaServerRunner) Completion(ctx context.Context, req CompletionReques
 				}
 
 				finalResp = CompletionResponse{
-					Content:            lsResp.Content,
+					Content:               lsResp.Content,
-					Done:               true,
+					Done:                  true,
-					DoneReason:         doneReason,
+					DoneReason:            doneReason,
-					PromptEvalCount:    lsResp.Timings.promptEvalCount(),
+					PromptEvalCount:       lsResp.Timings.promptEvalCount(),
-					PromptEvalDuration: time.Duration(lsResp.Timings.PromptMS * float64(time.Millisecond)),
+					PromptEvalCachedCount: lsResp.Timings.CacheN,
-					EvalCount:          lsResp.Timings.PredictN,
+					PromptEvalDuration:    time.Duration(lsResp.Timings.PromptMS * float64(time.Millisecond)),
-					EvalDuration:       time.Duration(lsResp.Timings.PredictMS * float64(time.Millisecond)),
+					EvalCount:             lsResp.Timings.PredictN,
+					EvalDuration:          time.Duration(lsResp.Timings.PredictMS * float64(time.Millisecond)),
 				}
 				hasFinalResp = true
 			}
@@ -1928,6 +1929,7 @@ func (s *llamaServerRunner) Chat(ctx context.Context, req ChatRequest, fn func(C
 				resp.Done = true
 				resp.DoneReason = doneReason
 				resp.PromptEvalCount = lsResp.Timings.promptEvalCount()
+				resp.PromptEvalCachedCount = lsResp.Timings.CacheN
 				resp.PromptEvalDuration = time.Duration(lsResp.Timings.PromptMS * float64(time.Millisecond))
 				resp.EvalCount = lsResp.Timings.PredictN
 				resp.EvalDuration = time.Duration(lsResp.Timings.PredictMS * float64(time.Millisecond))

llm/llama_server_test.go

@@ -291,6 +291,9 @@ func TestLlamaServerCompletionPromptEvalCountIncludesCache(t *testing.T) {
 	if responses[0].PromptEvalCount != 17 {
 		t.Errorf("PromptEvalCount = %d, want 17", responses[0].PromptEvalCount)
 	}
+	if responses[0].PromptEvalCachedCount != 12 {
+		t.Errorf("PromptEvalCachedCount = %d, want 12", responses[0].PromptEvalCachedCount)
+	}
 	if responses[0].PromptEvalDuration != 10*time.Millisecond {
 		t.Errorf("PromptEvalDuration = %s, want 10ms", responses[0].PromptEvalDuration)
 	}
@@ -341,6 +344,9 @@ func TestLlamaServerChatPromptEvalCountIncludesCache(t *testing.T) {
 	if responses[1].PromptEvalCount != 17 {
 		t.Errorf("PromptEvalCount = %d, want 17", responses[1].PromptEvalCount)
 	}
+	if responses[1].PromptEvalCachedCount != 12 {
+		t.Errorf("PromptEvalCachedCount = %d, want 12", responses[1].PromptEvalCachedCount)
+	}
 	if responses[1].PromptEvalDuration != 10*time.Millisecond {
 		t.Errorf("PromptEvalDuration = %s, want 10ms", responses[1].PromptEvalDuration)
 	}

llm/server.go

@@ -242,14 +242,15 @@ type ChatRequest struct {
 }
 
 type ChatResponse struct {
-	Message            api.Message   `json:"message"`
+	Message               api.Message   `json:"message"`
-	DoneReason         DoneReason    `json:"done_reason"`
+	DoneReason            DoneReason    `json:"done_reason"`
-	Done               bool          `json:"done"`
+	Done                  bool          `json:"done"`
-	PromptEvalCount    int           `json:"prompt_eval_count"`
+	PromptEvalCount       int           `json:"prompt_eval_count"`
-	PromptEvalDuration time.Duration `json:"prompt_eval_duration"`
+	PromptEvalCachedCount int           `json:"prompt_eval_cached_count"`
-	EvalCount          int           `json:"eval_count"`
+	PromptEvalDuration    time.Duration `json:"prompt_eval_duration"`
-	EvalDuration       time.Duration `json:"eval_duration"`
+	EvalCount             int           `json:"eval_count"`
-	Logprobs           []Logprob     `json:"logprobs,omitempty"`
+	EvalDuration          time.Duration `json:"eval_duration"`
+	Logprobs              []Logprob     `json:"logprobs,omitempty"`
 }
 
 // DoneReason represents the reason why a completion response is done
@@ -285,13 +286,14 @@ type Logprob struct {
 }
 
 type CompletionResponse struct {
-	Content            string        `json:"content"`
+	Content               string        `json:"content"`
-	DoneReason         DoneReason    `json:"done_reason"`
+	DoneReason            DoneReason    `json:"done_reason"`
-	Done               bool          `json:"done"`
+	Done                  bool          `json:"done"`
-	PromptEvalCount    int           `json:"prompt_eval_count"`
+	PromptEvalCount       int           `json:"prompt_eval_count"`
-	PromptEvalDuration time.Duration `json:"prompt_eval_duration"`
+	PromptEvalCachedCount int           `json:"prompt_eval_cached_count"`
-	EvalCount          int           `json:"eval_count"`
+	PromptEvalDuration    time.Duration `json:"prompt_eval_duration"`
-	EvalDuration       time.Duration `json:"eval_duration"`
+	EvalCount             int           `json:"eval_count"`
+	EvalDuration          time.Duration `json:"eval_duration"`
 
 	// Logprobs contains log probability information if requested
 	Logprobs []Logprob `json:"logprobs,omitempty"`

middleware/anthropic.go

@@ -101,13 +101,13 @@ type WebSearchAnthropicWriter struct {
 
 	terminalSent bool
 
-	observedPromptEvalCount int
+	observedPromptEvalCount       int
-	observedEvalCount       int
+	observedPromptEvalCachedCount int
+	observedEvalCount             int
 
-	loopInFlight      bool
+	loopInFlight  bool
-	loopBaseInputTok  int
+	loopBaseUsage anthropic.Usage
-	loopBaseOutputTok int
+	loopResultCh  chan webSearchLoopResult
-	loopResultCh      chan webSearchLoopResult
 
 	streamMessageStarted bool
 	streamHasOpenBlock   bool
@@ -201,10 +201,7 @@ func (w *WebSearchAnthropicWriter) Write(data []byte) (int, error) {
 	loopCtx, cancel := w.startLoopContext()
 	defer cancel()
 
-	initialUsage := anthropic.Usage{
+	initialUsage := w.usageWithObservedMetrics(chatResponse.Metrics)
-		InputTokens:  max(w.observedPromptEvalCount, chatResponse.Metrics.PromptEvalCount),
-		OutputTokens: max(w.observedEvalCount, chatResponse.Metrics.EvalCount),
-	}
 	logutil.Trace("anthropic middleware: starting sync web_search loop",
 		"tool_call", anthropic.TraceToolCall(webSearchCall),
 		"resp", anthropic.TraceChatResponse(chatResponse),
@@ -319,8 +316,7 @@ func (w *WebSearchAnthropicWriter) runWebSearchLoop(ctx context.Context, initial
 			"resp", anthropic.TraceChatResponse(followUpResponse),
 		)
 
-		usage.InputTokens += followUpResponse.Metrics.PromptEvalCount
+		usage.Add(anthropic.UsageFromMetrics(followUpResponse.Metrics))
-		usage.OutputTokens += followUpResponse.Metrics.EvalCount
 
 		nextToolCall, hasWebSearch, hasOtherTools := findWebSearchToolCall(followUpResponse.Message.ToolCalls)
 		if hasWebSearch && hasOtherTools {
@@ -380,12 +376,8 @@ func (w *WebSearchAnthropicWriter) startLoopWorker(initialResponse api.ChatRespo
 		return
 	}
 
-	initialUsage := anthropic.Usage{
+	initialUsage := w.usageWithObservedMetrics(initialResponse.Metrics)
-		InputTokens:  max(w.observedPromptEvalCount, initialResponse.Metrics.PromptEvalCount),
+	w.loopBaseUsage = initialUsage
-		OutputTokens: max(w.observedEvalCount, initialResponse.Metrics.EvalCount),
-	}
-	w.loopBaseInputTok = initialUsage.InputTokens
-	w.loopBaseOutputTok = initialUsage.OutputTokens
 	w.loopResultCh = make(chan webSearchLoopResult, 1)
 	w.loopInFlight = true
 	logutil.Trace("anthropic middleware: loop worker started",
@@ -438,25 +430,42 @@ func (w *WebSearchAnthropicWriter) recordObservedUsage(metrics api.Metrics) {
 	if metrics.PromptEvalCount > w.observedPromptEvalCount {
 		w.observedPromptEvalCount = metrics.PromptEvalCount
 	}
+	if metrics.PromptEvalCachedCount > w.observedPromptEvalCachedCount {
+		w.observedPromptEvalCachedCount = metrics.PromptEvalCachedCount
+	}
 	if metrics.EvalCount > w.observedEvalCount {
 		w.observedEvalCount = metrics.EvalCount
 	}
 }
 
 func (w *WebSearchAnthropicWriter) applyObservedUsageDeltaToUsage(usage *anthropic.Usage) {
-	if deltaIn := w.observedPromptEvalCount - w.loopBaseInputTok; deltaIn > 0 {
+	observed := w.currentObservedUsage()
-		usage.InputTokens += deltaIn
+	usage.InputTokens += observed.InputTokens - w.loopBaseUsage.InputTokens
-	}
+	usage.CacheCreationInputTokens += observed.CacheCreationInputTokens - w.loopBaseUsage.CacheCreationInputTokens
-	if deltaOut := w.observedEvalCount - w.loopBaseOutputTok; deltaOut > 0 {
+	usage.CacheReadInputTokens += observed.CacheReadInputTokens - w.loopBaseUsage.CacheReadInputTokens
-		usage.OutputTokens += deltaOut
+	usage.OutputTokens += observed.OutputTokens - w.loopBaseUsage.OutputTokens
-	}
 }
 
 func (w *WebSearchAnthropicWriter) currentObservedUsage() anthropic.Usage {
-	return anthropic.Usage{
+	return anthropic.UsageFromMetrics(api.Metrics{
-		InputTokens:  w.observedPromptEvalCount,
+		PromptEvalCount:       w.observedPromptEvalCount,
-		OutputTokens: w.observedEvalCount,
+		PromptEvalCachedCount: w.observedPromptEvalCachedCount,
+		EvalCount:             w.observedEvalCount,
+	})
+}
+
+func (w *WebSearchAnthropicWriter) usageWithObservedMetrics(metrics api.Metrics) anthropic.Usage {
+	if w.observedPromptEvalCount > metrics.PromptEvalCount {
+		metrics.PromptEvalCount = w.observedPromptEvalCount
 	}
+	if w.observedPromptEvalCachedCount > metrics.PromptEvalCachedCount {
+		metrics.PromptEvalCachedCount = w.observedPromptEvalCachedCount
+	}
+	if w.observedEvalCount > metrics.EvalCount {
+		metrics.EvalCount = w.observedEvalCount
+	}
+
+	return anthropic.UsageFromMetrics(metrics)
 }
 
 func (w *WebSearchAnthropicWriter) startLoopContext() (context.Context, context.CancelFunc) {
@@ -625,7 +634,7 @@ func (w *WebSearchAnthropicWriter) ensureStreamMessageStart(usage anthropic.Usag
 	}
 
 	inputTokens := usage.InputTokens
-	if inputTokens == 0 {
+	if inputTokens == 0 && usage.CacheCreationInputTokens == 0 && usage.CacheReadInputTokens == 0 {
 		inputTokens = w.estimatedInputTokens
 	}
 
@@ -638,7 +647,9 @@ func (w *WebSearchAnthropicWriter) ensureStreamMessageStart(usage anthropic.Usag
 			Model:   w.req.Model,
 			Content: []anthropic.ContentBlock{},
 			Usage: anthropic.Usage{
-				InputTokens: inputTokens,
+				InputTokens:              inputTokens,
+				CacheCreationInputTokens: usage.CacheCreationInputTokens,
+				CacheReadInputTokens:     usage.CacheReadInputTokens,
 			},
 		},
 	}); err != nil {
@@ -751,8 +762,10 @@ func (w *WebSearchAnthropicWriter) writeTerminalResponse(response anthropic.Mess
 			StopReason: response.StopReason,
 		},
 		Usage: anthropic.DeltaUsage{
-			InputTokens:  response.Usage.InputTokens,
+			InputTokens:              response.Usage.InputTokens,
-			OutputTokens: response.Usage.OutputTokens,
+			CacheCreationInputTokens: response.Usage.CacheCreationInputTokens,
+			CacheReadInputTokens:     response.Usage.CacheReadInputTokens,
+			OutputTokens:             response.Usage.OutputTokens,
 		},
 	}); err != nil {
 		return err

middleware/anthropic_test.go

@@ -2164,7 +2164,7 @@ func TestWebSearchStreamingUsageUsesObservedChunkMetrics(t *testing.T) {
 			Message:    api.Message{Role: "assistant", Content: "After search."},
 			Done:       true,
 			DoneReason: "stop",
-			Metrics:    api.Metrics{PromptEvalCount: 20, EvalCount: 7},
+			Metrics:    api.Metrics{PromptEvalCount: 20, PromptEvalCachedCount: 5, EvalCount: 7},
 		}
 		_ = json.NewEncoder(w).Encode(resp)
 	}))
@@ -2192,7 +2192,7 @@ func TestWebSearchStreamingUsageUsesObservedChunkMetrics(t *testing.T) {
 				Model:   "test-model",
 				Message: api.Message{Role: "assistant", Content: "Preface "},
 				Done:    false,
-				Metrics: api.Metrics{PromptEvalCount: 12, EvalCount: 4},
+				Metrics: api.Metrics{PromptEvalCount: 12, PromptEvalCachedCount: 4, EvalCount: 4},
 			},
 			{
 				Model: "test-model",
@@ -2216,7 +2216,7 @@ func TestWebSearchStreamingUsageUsesObservedChunkMetrics(t *testing.T) {
 				Message:    api.Message{Role: "assistant"},
 				Done:       true,
 				DoneReason: "stop",
-				Metrics:    api.Metrics{PromptEvalCount: 12, EvalCount: 4},
+				Metrics:    api.Metrics{PromptEvalCount: 12, PromptEvalCachedCount: 4, EvalCount: 4},
 			},
 		}
 		c.Writer.WriteHeader(http.StatusOK)
@@ -2259,8 +2259,11 @@ func TestWebSearchStreamingUsageUsesObservedChunkMetrics(t *testing.T) {
 	if !found {
 		t.Fatal("expected message_delta event")
 	}
-	if messageDelta.Usage.InputTokens != 32 {
+	if messageDelta.Usage.InputTokens != 23 {
-		t.Fatalf("expected aggregated input tokens 32 (12 passthrough + 20 followup), got %d", messageDelta.Usage.InputTokens)
+		t.Fatalf("expected aggregated fresh input tokens 23 ((12-4) passthrough + (20-5) followup), got %d", messageDelta.Usage.InputTokens)
+	}
+	if messageDelta.Usage.CacheReadInputTokens != 9 {
+		t.Fatalf("expected aggregated cache read tokens 9 (4 passthrough + 5 followup), got %d", messageDelta.Usage.CacheReadInputTokens)
 	}
 	if messageDelta.Usage.OutputTokens != 11 {
 		t.Fatalf("expected aggregated output tokens 11 (4 passthrough + 7 followup), got %d", messageDelta.Usage.OutputTokens)

openai/openai.go

@@ -65,10 +65,15 @@ type CompleteChunkChoice struct {
 	Logprobs     *ChoiceLogprobs `json:"logprobs,omitempty"`
 }
 
+type PromptTokensDetails struct {
+	CachedTokens int `json:"cached_tokens"`
+}
+
 type Usage struct {
-	PromptTokens     int `json:"prompt_tokens"`
+	PromptTokens        int                 `json:"prompt_tokens"`
-	CompletionTokens int `json:"completion_tokens"`
+	PromptTokensDetails PromptTokensDetails `json:"prompt_tokens_details"`
-	TotalTokens      int `json:"total_tokens"`
+	CompletionTokens    int                 `json:"completion_tokens"`
+	TotalTokens         int                 `json:"total_tokens"`
 }
 
 type ResponseFormat struct {
@@ -232,9 +237,10 @@ func NewError(code int, message string) ErrorResponse {
 // ToUsage converts an api.ChatResponse to Usage
 func ToUsage(r api.ChatResponse) Usage {
 	return Usage{
-		PromptTokens:     r.Metrics.PromptEvalCount,
+		PromptTokens:        r.Metrics.PromptEvalCount,
-		CompletionTokens: r.Metrics.EvalCount,
+		PromptTokensDetails: PromptTokensDetails{CachedTokens: r.Metrics.PromptEvalCachedCount},
-		TotalTokens:      r.Metrics.PromptEvalCount + r.Metrics.EvalCount,
+		CompletionTokens:    r.Metrics.EvalCount,
+		TotalTokens:         r.Metrics.PromptEvalCount + r.Metrics.EvalCount,
 	}
 }
 
@@ -355,9 +361,10 @@ func ToChunk(id string, r api.ChatResponse, toolCallSent bool) ChatCompletionChu
 // ToUsageGenerate converts an api.GenerateResponse to Usage
 func ToUsageGenerate(r api.GenerateResponse) Usage {
 	return Usage{
-		PromptTokens:     r.Metrics.PromptEvalCount,
+		PromptTokens:        r.Metrics.PromptEvalCount,
-		CompletionTokens: r.Metrics.EvalCount,
+		PromptTokensDetails: PromptTokensDetails{CachedTokens: r.Metrics.PromptEvalCachedCount},
-		TotalTokens:      r.Metrics.PromptEvalCount + r.Metrics.EvalCount,
+		CompletionTokens:    r.Metrics.EvalCount,
+		TotalTokens:         r.Metrics.PromptEvalCount + r.Metrics.EvalCount,
 	}
 }
 

openai/openai_test.go

@@ -176,8 +176,9 @@ func TestFromCompleteRequest_Basic(t *testing.T) {
 func TestToUsage(t *testing.T) {
 	resp := api.ChatResponse{
 		Metrics: api.Metrics{
-			PromptEvalCount: 10,
+			PromptEvalCount:       10,
-			EvalCount:       20,
+			PromptEvalCachedCount: 4,
+			EvalCount:             20,
 		},
 	}
 
@@ -187,6 +188,10 @@ func TestToUsage(t *testing.T) {
 		t.Errorf("expected PromptTokens 10, got %d", usage.PromptTokens)
 	}
 
+	if usage.PromptTokensDetails.CachedTokens != 4 {
+		t.Errorf("expected CachedTokens 4, got %d", usage.PromptTokensDetails.CachedTokens)
+	}
+
 	if usage.CompletionTokens != 20 {
 		t.Errorf("expected CompletionTokens 20, got %d", usage.CompletionTokens)
 	}

openai/responses.go

@@ -856,11 +856,10 @@ func ToResponse(model, responseID, itemID string, chatResponse api.ChatResponse,
 		Temperature:        derefFloat64(request.Temperature, 1.0),
 		Reasoning:          reasoning,
 		Usage: &ResponsesUsage{
-			InputTokens:  chatResponse.PromptEvalCount,
+			InputTokens:        chatResponse.PromptEvalCount,
-			OutputTokens: chatResponse.EvalCount,
+			OutputTokens:       chatResponse.EvalCount,
-			TotalTokens:  chatResponse.PromptEvalCount + chatResponse.EvalCount,
+			TotalTokens:        chatResponse.PromptEvalCount + chatResponse.EvalCount,
-			// TODO(drifkin): wire through the actual values
+			InputTokensDetails: ResponsesInputTokensDetails{CachedTokens: chatResponse.PromptEvalCachedCount},
-			InputTokensDetails: ResponsesInputTokensDetails{CachedTokens: 0},
 			// TODO(drifkin): wire through the actual values
 			OutputTokensDetails: ResponsesOutputTokensDetails{ReasoningTokens: 0},
 		},
@@ -1366,7 +1365,7 @@ func (c *ResponsesStreamConverter) processCompletion(r api.ChatResponse) []Respo
 		"output_tokens": r.EvalCount,
 		"total_tokens":  r.PromptEvalCount + r.EvalCount,
 		"input_tokens_details": map[string]any{
-			"cached_tokens": 0,
+			"cached_tokens": r.PromptEvalCachedCount,
 		},
 		"output_tokens_details": map[string]any{
 			"reasoning_tokens": 0,

openai/responses_test.go

@@ -1506,6 +1506,32 @@ func TestToResponse_WithReasoning(t *testing.T) {
 	}
 }
 
+func TestToResponse_UsageIncludesCachedTokens(t *testing.T) {
+	response := ToResponse("gpt-oss:20b", "resp_123", "msg_456", api.ChatResponse{
+		CreatedAt: time.Now(),
+		Message:   api.Message{Content: "The answer is 42"},
+		Done:      true,
+		Metrics: api.Metrics{
+			PromptEvalCount:       10,
+			PromptEvalCachedCount: 4,
+			EvalCount:             3,
+		},
+	}, ResponsesRequest{})
+
+	if response.Usage == nil {
+		t.Fatal("expected usage")
+	}
+	if response.Usage.InputTokens != 10 {
+		t.Errorf("InputTokens = %d, want 10", response.Usage.InputTokens)
+	}
+	if response.Usage.InputTokensDetails.CachedTokens != 4 {
+		t.Errorf("CachedTokens = %d, want 4", response.Usage.InputTokensDetails.CachedTokens)
+	}
+	if response.Usage.TotalTokens != 13 {
+		t.Errorf("TotalTokens = %d, want 13", response.Usage.TotalTokens)
+	}
+}
+
 func TestFromResponsesRequest_Instructions(t *testing.T) {
 	reqJSON := `{
 		"model": "gpt-oss:20b",
@@ -1858,6 +1884,11 @@ func TestResponsesStreamConverter_OutputIncludesContent(t *testing.T) {
 	events := converter.Process(api.ChatResponse{
 		Message: api.Message{},
 		Done:    true,
+		Metrics: api.Metrics{
+			PromptEvalCount:       10,
+			PromptEvalCachedCount: 4,
+			EvalCount:             3,
+		},
 	})
 
 	// Find the output_item.done event
@@ -1906,6 +1937,11 @@ func TestResponsesStreamConverter_ResponseCompletedIncludesOutput(t *testing.T)
 	events := converter.Process(api.ChatResponse{
 		Message: api.Message{},
 		Done:    true,
+		Metrics: api.Metrics{
+			PromptEvalCount:       10,
+			PromptEvalCachedCount: 4,
+			EvalCount:             3,
+		},
 	})
 
 	// Find the response.completed event
@@ -1935,6 +1971,12 @@ func TestResponsesStreamConverter_ResponseCompletedIncludesOutput(t *testing.T)
 	if item["type"] != "message" {
 		t.Errorf("output[0].type = %q, want %q", item["type"], "message")
 	}
+
+	usage := response["usage"].(map[string]any)
+	inputTokensDetails := usage["input_tokens_details"].(map[string]any)
+	if inputTokensDetails["cached_tokens"] != 4 {
+		t.Errorf("cached_tokens = %v, want 4", inputTokensDetails["cached_tokens"])
+	}
 }
 
 func TestResponsesStreamConverter_ResponseCreatedIncludesOutput(t *testing.T) {

server/routes.go

@@ -681,10 +681,11 @@ func (s *Server) GenerateHandler(c *gin.Context) {
 				Response:  cr.Content,
 				Done:      cr.Done,
 				Metrics: api.Metrics{
-					PromptEvalCount:    cr.PromptEvalCount,
+					PromptEvalCount:       cr.PromptEvalCount,
-					PromptEvalDuration: cr.PromptEvalDuration,
+					PromptEvalCachedCount: cr.PromptEvalCachedCount,
-					EvalCount:          cr.EvalCount,
+					PromptEvalDuration:    cr.PromptEvalDuration,
-					EvalDuration:       cr.EvalDuration,
+					EvalCount:             cr.EvalCount,
+					EvalDuration:          cr.EvalDuration,
 				},
 				Logprobs: toAPILogprobs(cr.Logprobs),
 			}
@@ -2814,10 +2815,11 @@ func (s *Server) ChatHandler(c *gin.Context) {
 					Message:   api.Message{Role: "assistant", Content: r.Content},
 					Done:      r.Done,
 					Metrics: api.Metrics{
-						PromptEvalCount:    r.PromptEvalCount,
+						PromptEvalCount:       r.PromptEvalCount,
-						PromptEvalDuration: r.PromptEvalDuration,
+						PromptEvalCachedCount: r.PromptEvalCachedCount,
-						EvalCount:          r.EvalCount,
+						PromptEvalDuration:    r.PromptEvalDuration,
-						EvalDuration:       r.EvalDuration,
+						EvalCount:             r.EvalCount,
+						EvalDuration:          r.EvalDuration,
 					},
 					Logprobs: toAPILogprobs(r.Logprobs),
 				}
@@ -3022,10 +3024,11 @@ func (s *Server) handleNativeChat(c *gin.Context, req api.ChatRequest, m *Model,
 				Message:   r.Message,
 				Done:      r.Done,
 				Metrics: api.Metrics{
-					PromptEvalCount:    r.PromptEvalCount,
+					PromptEvalCount:       r.PromptEvalCount,
-					PromptEvalDuration: r.PromptEvalDuration,
+					PromptEvalCachedCount: r.PromptEvalCachedCount,
-					EvalCount:          r.EvalCount,
+					PromptEvalDuration:    r.PromptEvalDuration,
-					EvalDuration:       r.EvalDuration,
+					EvalCount:             r.EvalCount,
+					EvalDuration:          r.EvalDuration,
 				},
 				Logprobs: toAPILogprobs(r.Logprobs),
 			}

server/routes_generate_test.go

@@ -754,12 +754,13 @@ func TestGenerateChat(t *testing.T) {
 
 	mock := mockRunner{
 		CompletionResponse: llm.CompletionResponse{
-			Done:               true,
+			Done:                  true,
-			DoneReason:         llm.DoneReasonStop,
+			DoneReason:            llm.DoneReasonStop,
-			PromptEvalCount:    1,
+			PromptEvalCount:       1,
-			PromptEvalDuration: 1,
+			PromptEvalCachedCount: 1,
-			EvalCount:          1,
+			PromptEvalDuration:    1,
-			EvalDuration:       1,
+			EvalCount:             1,
+			EvalDuration:          1,
 		},
 	}
 
@@ -972,6 +973,10 @@ func TestGenerateChat(t *testing.T) {
 			t.Errorf("expected prompt eval count > 0, got 0")
 		}
 
+		if actual.PromptEvalCachedCount != 1 {
+			t.Errorf("expected prompt eval cached count 1, got %d", actual.PromptEvalCachedCount)
+		}
+
 		if actual.PromptEvalDuration == 0 {
 			t.Errorf("expected prompt eval duration > 0, got 0")
 		}
@@ -1471,12 +1476,13 @@ func TestGenerate(t *testing.T) {
 
 	mock := mockRunner{
 		CompletionResponse: llm.CompletionResponse{
-			Done:               true,
+			Done:                  true,
-			DoneReason:         llm.DoneReasonStop,
+			DoneReason:            llm.DoneReasonStop,
-			PromptEvalCount:    1,
+			PromptEvalCount:       1,
-			PromptEvalDuration: 1,
+			PromptEvalCachedCount: 1,
-			EvalCount:          1,
+			PromptEvalDuration:    1,
-			EvalDuration:       1,
+			EvalCount:             1,
+			EvalDuration:          1,
 		},
 	}
 
@@ -1669,6 +1675,10 @@ func TestGenerate(t *testing.T) {
 			t.Errorf("expected prompt eval count > 0, got 0")
 		}
 
+		if actual.PromptEvalCachedCount != 1 {
+			t.Errorf("expected prompt eval cached count 1, got %d", actual.PromptEvalCachedCount)
+		}
+
 		if actual.PromptEvalDuration == 0 {
 			t.Errorf("expected prompt eval duration > 0, got 0")
 		}

x/mlxrunner/client.go

@@ -107,10 +107,11 @@ type CompletionResponse struct {
 	Done       bool
 	DoneReason int
 
-	PromptEvalCount    int
+	PromptEvalCount       int
-	PromptEvalDuration time.Duration
+	PromptEvalCachedCount int
-	EvalCount          int
+	PromptEvalDuration    time.Duration
-	EvalDuration       time.Duration
+	EvalCount             int
+	EvalDuration          time.Duration
 
 	Logprobs []llm.Logprob
 
@@ -186,14 +187,15 @@ func (c *Client) Completion(ctx context.Context, req llm.CompletionRequest, fn f
 		}
 
 		cresp := llm.CompletionResponse{
-			Content:            raw.Content,
+			Content:               raw.Content,
-			Done:               raw.Done,
+			Done:                  raw.Done,
-			DoneReason:         llm.DoneReason(raw.DoneReason),
+			DoneReason:            llm.DoneReason(raw.DoneReason),
-			PromptEvalCount:    raw.PromptEvalCount,
+			PromptEvalCount:       raw.PromptEvalCount,
-			PromptEvalDuration: raw.PromptEvalDuration,
+			PromptEvalCachedCount: raw.PromptEvalCachedCount,
-			EvalCount:          raw.EvalCount,
+			PromptEvalDuration:    raw.PromptEvalDuration,
-			EvalDuration:       raw.EvalDuration,
+			EvalCount:             raw.EvalCount,
-			Logprobs:           raw.Logprobs,
+			EvalDuration:          raw.EvalDuration,
+			Logprobs:              raw.Logprobs,
 		}
 
 		fn(cresp)

x/mlxrunner/pipeline.go

@@ -189,7 +189,12 @@ func (r *Runner) decode(ctx context.Context, request Request, session *cacheSess
 		wantTopLogprobs: request.SamplerOpts.TopLogprobs,
 	}
 
-	final := CompletionResponse{Done: true, PromptEvalCount: len(request.Tokens), DoneReason: 1}
+	final := CompletionResponse{
+		Done:                  true,
+		PromptEvalCount:       len(request.Tokens),
+		PromptEvalCachedCount: len(session.inputs) - len(session.remaining),
+		DoneReason:            1,
+	}
 	final.PromptEvalDuration = promptEval
 	now := time.Now()