Fix SSE keep-alive passthrough, content-filter stop, and usage token propagation

internal/adapter/claude/handler_messages.go

@@ -90,6 +90,11 @@ func (h *Handler) Messages(w http.ResponseWriter, r *http.Request) {
 		result.Text,
 		stdReq.ToolNames,
 	)
+	if result.OutputTokens > 0 {
+		if usage, ok := respBody["usage"].(map[string]any); ok {
+			usage["output_tokens"] = result.OutputTokens
+		}
+	}
 	writeJSON(w, http.StatusOK, respBody)
 }
 

internal/adapter/claude/stream_runtime_core.go

@@ -26,6 +26,7 @@ type claudeStreamRuntime struct {
 	messageID string
 	thinking  strings.Builder
 	text      strings.Builder
+	outputTokens int
 
 	nextBlockIndex     int
 	thinkingBlockOpen  bool
@@ -66,6 +67,9 @@ func (s *claudeStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Parse
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
+	if parsed.OutputTokens > 0 {
+		s.outputTokens = parsed.OutputTokens
+	}
 	if parsed.ErrorMessage != "" {
 		s.upstreamErr = parsed.ErrorMessage
 		return streamengine.ParsedDecision{Stop: true, StopReason: streamengine.StopReason("upstream_error")}

internal/adapter/claude/stream_runtime_finalize.go

@@ -108,6 +108,9 @@ func (s *claudeStreamRuntime) finalize(stopReason string) {
 	}
 
 	outputTokens := util.EstimateTokens(finalThinking) + util.EstimateTokens(finalText)
+	if s.outputTokens > 0 {
+		outputTokens = s.outputTokens
+	}
 	s.send("message_delta", map[string]any{
 		"type": "message_delta",
 		"delta": map[string]any{

internal/adapter/gemini/handler_generate.go

@@ -174,12 +174,12 @@ func (h *Handler) handleNonStreamGenerateContent(w http.ResponseWriter, resp *ht
 	}
 
 	result := sse.CollectStream(resp, thinkingEnabled, true)
-	writeJSON(w, http.StatusOK, buildGeminiGenerateContentResponse(model, finalPrompt, result.Thinking, result.Text, toolNames))
+	writeJSON(w, http.StatusOK, buildGeminiGenerateContentResponse(model, finalPrompt, result.Thinking, result.Text, toolNames, result.OutputTokens))
 }
 
-func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, finalText string, toolNames []string) map[string]any {
+func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, finalText string, toolNames []string, outputTokens int) map[string]any {
 	parts := buildGeminiPartsFromFinal(finalText, finalThinking, toolNames)
-	usage := buildGeminiUsage(finalPrompt, finalThinking, finalText)
+	usage := buildGeminiUsage(finalPrompt, finalThinking, finalText, outputTokens)
 	return map[string]any{
 		"candidates": []map[string]any{
 			{
@@ -196,10 +196,14 @@ func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, final
 	}
 }
 
-func buildGeminiUsage(finalPrompt, finalThinking, finalText string) map[string]any {
+func buildGeminiUsage(finalPrompt, finalThinking, finalText string, outputTokens int) map[string]any {
 	promptTokens := util.EstimateTokens(finalPrompt)
 	reasoningTokens := util.EstimateTokens(finalThinking)
 	completionTokens := util.EstimateTokens(finalText)
+	if outputTokens > 0 {
+		completionTokens = outputTokens
+		reasoningTokens = 0
+	}
 	return map[string]any{
 		"promptTokenCount":     promptTokens,
 		"candidatesTokenCount": reasoningTokens + completionTokens,

internal/adapter/gemini/handler_stream_runtime.go

@@ -64,6 +64,7 @@ type geminiStreamRuntime struct {
 
 	thinking strings.Builder
 	text     strings.Builder
+	outputTokens int
 }
 
 func newGeminiStreamRuntime(
@@ -103,6 +104,9 @@ func (s *geminiStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Parse
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
+	if parsed.OutputTokens > 0 {
+		s.outputTokens = parsed.OutputTokens
+	}
 	if parsed.ContentFilter || parsed.ErrorMessage != "" || parsed.Stop {
 		return streamengine.ParsedDecision{Stop: true}
 	}
@@ -176,6 +180,6 @@ func (s *geminiStreamRuntime) finalize() {
 			},
 		},
 		"modelVersion":  s.model,
-		"usageMetadata": buildGeminiUsage(s.finalPrompt, finalThinking, finalText),
+		"usageMetadata": buildGeminiUsage(s.finalPrompt, finalThinking, finalText, s.outputTokens),
 	})
 }

internal/adapter/openai/chat_stream_runtime.go

@@ -36,6 +36,7 @@ type chatStreamRuntime struct {
 	streamToolNames   map[int]string
 	thinking          strings.Builder
 	text              strings.Builder
+	outputTokens      int
 }
 
 func newChatStreamRuntime(
@@ -165,12 +166,19 @@ func (s *chatStreamRuntime) finalize(finishReason string) {
 	if len(detected.Calls) > 0 || s.toolCallsEmitted {
 		finishReason = "tool_calls"
 	}
+	usage := openaifmt.BuildChatUsage(s.finalPrompt, finalThinking, finalText)
+	if s.outputTokens > 0 {
+		usage["completion_tokens"] = s.outputTokens
+		if prompt, ok := usage["prompt_tokens"].(int); ok {
+			usage["total_tokens"] = prompt + s.outputTokens
+		}
+	}
 	s.sendChunk(openaifmt.BuildChatStreamChunk(
 		s.completionID,
 		s.created,
 		s.model,
 		[]map[string]any{openaifmt.BuildChatStreamFinishChoice(0, finishReason)},
-		openaifmt.BuildChatUsage(s.finalPrompt, finalThinking, finalText),
+		usage,
 	))
 	s.sendDone()
 }
@@ -179,6 +187,9 @@ func (s *chatStreamRuntime) onParsed(parsed sse.LineResult) streamengine.ParsedD
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
+	if parsed.OutputTokens > 0 {
+		s.outputTokens = parsed.OutputTokens
+	}
 	if parsed.ContentFilter || parsed.ErrorMessage != "" {
 		return streamengine.ParsedDecision{Stop: true, StopReason: streamengine.StopReason("content_filter")}
 	}

internal/adapter/openai/handler_chat.go

@@ -107,6 +107,14 @@ func (h *Handler) handleNonStream(w http.ResponseWriter, ctx context.Context, re
 	finalThinking := result.Thinking
 	finalText := sanitizeLeakedOutput(result.Text)
 	respBody := openaifmt.BuildChatCompletion(completionID, model, finalPrompt, finalThinking, finalText, toolNames)
+	if result.OutputTokens > 0 {
+		if usage, ok := respBody["usage"].(map[string]any); ok {
+			usage["completion_tokens"] = result.OutputTokens
+			if prompt, ok := usage["prompt_tokens"].(int); ok {
+				usage["total_tokens"] = prompt + result.OutputTokens
+			}
+		}
+	}
 	writeJSON(w, http.StatusOK, respBody)
 }
 

internal/adapter/openai/responses_handler.go

@@ -124,6 +124,14 @@ func (h *Handler) handleResponsesNonStream(w http.ResponseWriter, resp *http.Res
 	}
 
 	responseObj := openaifmt.BuildResponseObject(responseID, model, finalPrompt, result.Thinking, sanitizedText, toolNames)
+	if result.OutputTokens > 0 {
+		if usage, ok := responseObj["usage"].(map[string]any); ok {
+			usage["output_tokens"] = result.OutputTokens
+			if input, ok := usage["input_tokens"].(int); ok {
+				usage["total_tokens"] = input + result.OutputTokens
+			}
+		}
+	}
 	h.getResponseStore().put(owner, responseID, responseObj)
 	writeJSON(w, http.StatusOK, responseObj)
 }

internal/adapter/openai/responses_stream_runtime_core.go

@@ -49,6 +49,7 @@ type responsesStreamRuntime struct {
 	messagePartAdded  bool
 	sequence          int
 	failed            bool
+	outputTokens      int
 
 	persistResponse func(obj map[string]any)
 }
@@ -144,6 +145,14 @@ func (s *responsesStreamRuntime) finalize() {
 	s.closeIncompleteFunctionItems()
 
 	obj := s.buildCompletedResponseObject(finalThinking, finalText, detected)
+	if s.outputTokens > 0 {
+		if usage, ok := obj["usage"].(map[string]any); ok {
+			usage["output_tokens"] = s.outputTokens
+			if input, ok := usage["input_tokens"].(int); ok {
+				usage["total_tokens"] = input + s.outputTokens
+			}
+		}
+	}
 	if s.persistResponse != nil {
 		s.persistResponse(obj)
 	}
@@ -172,6 +181,9 @@ func (s *responsesStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Pa
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
+	if parsed.OutputTokens > 0 {
+		s.outputTokens = parsed.OutputTokens
+	}
 	if parsed.ContentFilter || parsed.ErrorMessage != "" || parsed.Stop {
 		return streamengine.ParsedDecision{Stop: true}
 	}

internal/sse/consumer.go

@@ -10,8 +10,9 @@ import (
 // CollectResult holds the aggregated text and thinking content from a
 // DeepSeek SSE stream, consumed to completion (non-streaming use case).
 type CollectResult struct {
-	Text     string
-	Thinking string
+	Text         string
+	Thinking     string
+	OutputTokens int
 }
 
 // CollectStream fully consumes a DeepSeek SSE response and separates
@@ -26,6 +27,7 @@ func CollectStream(resp *http.Response, thinkingEnabled bool, closeBody bool) Co
 	}
 	text := strings.Builder{}
 	thinking := strings.Builder{}
+	outputTokens := 0
 	currentType := "text"
 	if thinkingEnabled {
 		currentType = "thinking"
@@ -37,8 +39,14 @@ func CollectStream(resp *http.Response, thinkingEnabled bool, closeBody bool) Co
 			return true
 		}
 		if result.Stop {
+			if result.OutputTokens > 0 {
+				outputTokens = result.OutputTokens
+			}
 			return false
 		}
+		if result.OutputTokens > 0 {
+			outputTokens = result.OutputTokens
+		}
 		for _, p := range result.Parts {
 			if p.Type == "thinking" {
 				thinking.WriteString(p.Text)
@@ -48,5 +56,5 @@ func CollectStream(resp *http.Response, thinkingEnabled bool, closeBody bool) Co
 		}
 		return true
 	})
-	return CollectResult{Text: text.String(), Thinking: thinking.String()}
+	return CollectResult{Text: text.String(), Thinking: thinking.String(), OutputTokens: outputTokens}
 }

internal/sse/consumer_edge_test.go

@@ -138,3 +138,15 @@ func TestCollectStreamStatusFinished(t *testing.T) {
 		t.Fatalf("expected 'Hello', got %q", result.Text)
 	}
 }
+
+func TestCollectStreamStopsOnContentFilterStatus(t *testing.T) {
+	resp := makeHTTPResponse(
+		"data: {\"p\":\"response/content\",\"v\":\"safe\"}\n" +
+			"data: {\"p\":\"response/status\",\"v\":\"CONTENT_FILTER\"}\n" +
+			"data: {\"p\":\"response/content\",\"v\":\"blocked\"}\n",
+	)
+	result := CollectStream(resp, false, false)
+	if result.Text != "safe" {
+		t.Fatalf("expected stream to stop before blocked tail, got %q", result.Text)
+	}
+}

internal/sse/line.go

@@ -10,6 +10,7 @@ type LineResult struct {
 	ErrorMessage  string
 	Parts         []ContentPart
 	NextType      string
+	OutputTokens  int
 }
 
 // ParseDeepSeekContentLine centralizes one-line DeepSeek SSE parsing for both
@@ -39,6 +40,16 @@ func ParseDeepSeekContentLine(raw []byte, thinkingEnabled bool, currentType stri
 			NextType:      currentType,
 		}
 	}
+	if hasContentFilterStatus(chunk) {
+		return LineResult{
+			Parsed:        true,
+			Stop:          true,
+			ContentFilter: true,
+			ErrorMessage:  "content filtered by upstream",
+			NextType:      currentType,
+			OutputTokens:  extractAccumulatedTokenUsage(chunk),
+		}
+	}
 	parts, finished, nextType := ParseSSEChunkForContent(chunk, thinkingEnabled, currentType)
 	parts = filterLeakedContentFilterParts(parts)
 	return LineResult{
@@ -46,5 +57,6 @@ func ParseDeepSeekContentLine(raw []byte, thinkingEnabled bool, currentType stri
 		Stop:     finished,
 		Parts:    parts,
 		NextType: nextType,
+		OutputTokens: extractAccumulatedTokenUsage(chunk),
 	}
 }

internal/sse/line_test.go

@@ -26,6 +26,20 @@ func TestParseDeepSeekContentLineContentFilter(t *testing.T) {
 	}
 }
 
+func TestParseDeepSeekContentLineContentFilterStatus(t *testing.T) {
+	res := ParseDeepSeekContentLine([]byte(`data: {"p":"response/status","v":"CONTENT_FILTER"}`), false, "text")
+	if !res.Parsed || !res.Stop || !res.ContentFilter {
+		t.Fatalf("expected status-based content-filter stop result: %#v", res)
+	}
+}
+
+func TestParseDeepSeekContentLineCapturesAccumulatedTokenUsage(t *testing.T) {
+	res := ParseDeepSeekContentLine([]byte(`data: {"p":"response","o":"BATCH","v":[{"p":"accumulated_token_usage","v":1383},{"p":"quasi_status","v":"FINISHED"}]}`), false, "text")
+	if res.OutputTokens != 1383 {
+		t.Fatalf("expected output token usage 1383, got %d", res.OutputTokens)
+	}
+}
+
 func TestParseDeepSeekContentLineContent(t *testing.T) {
 	res := ParseDeepSeekContentLine([]byte(`data: {"p":"response/content","v":"hi"}`), false, "text")
 	if !res.Parsed || res.Stop {

internal/sse/parser.go

@@ -3,6 +3,7 @@ package sse
 import (
 	"bytes"
 	"encoding/json"
+	"math"
 	"strings"
 
 	"ds2api/internal/deepseek"
@@ -287,3 +288,86 @@ func extractContentRecursive(items []any, defaultType string) ([]ContentPart, bo
 func IsCitation(text string) bool {
 	return bytes.HasPrefix([]byte(strings.TrimSpace(text)), []byte("[citation:"))
 }
+
+func hasContentFilterStatus(chunk map[string]any) bool {
+	return hasContentFilterValue(chunk)
+}
+
+func hasContentFilterValue(v any) bool {
+	switch x := v.(type) {
+	case string:
+		return strings.EqualFold(strings.TrimSpace(x), "content_filter")
+	case []any:
+		for _, item := range x {
+			if hasContentFilterValue(item) {
+				return true
+			}
+		}
+	case map[string]any:
+		if p, _ := x["p"].(string); strings.Contains(strings.ToLower(p), "status") {
+			if s, _ := x["v"].(string); strings.EqualFold(strings.TrimSpace(s), "content_filter") {
+				return true
+			}
+		}
+		for _, vv := range x {
+			if hasContentFilterValue(vv) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func extractAccumulatedTokenUsage(chunk map[string]any) int {
+	return findAccumulatedTokenUsage(chunk)
+}
+
+func findAccumulatedTokenUsage(v any) int {
+	switch x := v.(type) {
+	case map[string]any:
+		if p, _ := x["p"].(string); strings.Contains(strings.ToLower(p), "accumulated_token_usage") {
+			if n, ok := toInt(x["v"]); ok && n > 0 {
+				return n
+			}
+		}
+		if n, ok := toInt(x["accumulated_token_usage"]); ok && n > 0 {
+			return n
+		}
+		for _, vv := range x {
+			if n := findAccumulatedTokenUsage(vv); n > 0 {
+				return n
+			}
+		}
+	case []any:
+		for _, item := range x {
+			if n := findAccumulatedTokenUsage(item); n > 0 {
+				return n
+			}
+		}
+	}
+	return 0
+}
+
+func toInt(v any) (int, bool) {
+	switch x := v.(type) {
+	case int:
+		return x, true
+	case int32:
+		return int(x), true
+	case int64:
+		return int(x), true
+	case float64:
+		if math.IsNaN(x) || math.IsInf(x, 0) {
+			return 0, false
+		}
+		return int(x), true
+	case json.Number:
+		i, err := x.Int64()
+		if err != nil {
+			return 0, false
+		}
+		return int(i), true
+	default:
+		return 0, false
+	}
+}

internal/translatorcliproxy/stream_writer.go

@@ -62,6 +62,18 @@ func (w *OpenAIStreamTranslatorWriter) Write(p []byte) (int, error) {
 		if len(trimmed) == 0 {
 			continue
 		}
+		if bytes.HasPrefix(trimmed, []byte(":")) {
+			if _, err := w.dst.Write(trimmed); err != nil {
+				return len(p), err
+			}
+			if _, err := w.dst.Write([]byte("\n\n")); err != nil {
+				return len(p), err
+			}
+			if f, ok := w.dst.(http.Flusher); ok {
+				f.Flush()
+			}
+			continue
+		}
 		if !bytes.HasPrefix(trimmed, []byte("data:")) {
 			continue
 		}

internal/translatorcliproxy/stream_writer_test.go

@@ -42,3 +42,16 @@ func TestOpenAIStreamTranslatorWriterGemini(t *testing.T) {
 		t.Fatalf("expected gemini stream payload, got: %s", body)
 	}
 }
+
+func TestOpenAIStreamTranslatorWriterPreservesKeepAliveComment(t *testing.T) {
+	rec := httptest.NewRecorder()
+	w := NewOpenAIStreamTranslatorWriter(rec, sdktranslator.FormatGemini, "gemini-2.5-pro", []byte(`{}`), []byte(`{}`))
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.WriteHeader(200)
+	_, _ = w.Write([]byte(": keep-alive\n\n"))
+
+	body := rec.Body.String()
+	if !strings.Contains(body, ": keep-alive\n\n") {
+		t.Fatalf("expected keep-alive comment passthrough, got %q", body)
+	}
+}