diff --git a/API.en.md b/API.en.md
index 2b83245..0238a42 100644
--- a/API.en.md
+++ b/API.en.md
@@ -384,6 +384,7 @@ Business auth required. Returns OpenAI-compatible embeddings shape.
 ## Claude-Compatible API
 
 Besides `/anthropic/v1/*`, DS2API also supports shortcut paths: `/v1/messages`, `/messages`, `/v1/messages/count_tokens`, `/messages/count_tokens`.
+Implementation-wise this path is unified on the OpenAI Chat Completions parse-and-translate pipeline to avoid maintaining divergent parsing chains.
 
 ### `GET /anthropic/v1/models`
 
@@ -518,6 +519,7 @@ Supported paths:
 - `/v1/models/{model}:streamGenerateContent` (compat path)
 
 Authentication is the same as other business routes (`Authorization: Bearer <token>` or `x-api-key`).
+Implementation-wise this path is unified on the OpenAI Chat Completions parse-and-translate pipeline to avoid maintaining divergent parsing chains.
 
 ### `POST /v1beta/models/{model}:generateContent`
 
diff --git a/API.md b/API.md
index 1caa984..d2eb1f0 100644
--- a/API.md
+++ b/API.md
@@ -390,6 +390,7 @@ data: [DONE]
 ## Claude 兼容接口
 
 除标准路径 `/anthropic/v1/*` 外，还支持快捷路径 `/v1/messages`、`/messages`、`/v1/messages/count_tokens`、`/messages/count_tokens`。
+实现上统一走 OpenAI Chat Completions 解析与回译链路，避免多套解析逻辑分叉维护。
 
 ### `GET /anthropic/v1/models`
 
@@ -524,6 +525,7 @@ data: {"type":"message_stop"}
 - `/v1/models/{model}:streamGenerateContent`（兼容路径）
 
 鉴权方式同业务接口（`Authorization: Bearer <token>` 或 `x-api-key`）。
+实现上统一走 OpenAI Chat Completions 解析与回译链路，避免多套解析逻辑分叉维护。
 
 ### `POST /v1beta/models/{model}:generateContent`
 
diff --git a/internal/adapter/gemini/handler_generate.go b/internal/adapter/gemini/handler_generate.go
index 56cc0e6..b03b3ea 100644
--- a/internal/adapter/gemini/handler_generate.go
+++ b/internal/adapter/gemini/handler_generate.go
@@ -149,15 +149,14 @@ func (h *Handler) handleNonStreamGenerateContent(w http.ResponseWriter, resp *ht
 		cleanVisibleOutput(result.Thinking, stripReferenceMarkers),
 		cleanVisibleOutput(result.Text, stripReferenceMarkers),
 		toolNames,
-		result.PromptTokens,
 		result.OutputTokens,
 	))
 }
 
 //nolint:unused // retained for native Gemini non-stream handling path.
-func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, finalText string, toolNames []string, promptTokens, outputTokens int) 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, promptTokens, outputTokens)
+	usage := buildGeminiUsage(finalPrompt, finalThinking, finalText, outputTokens)
 	return map[string]any{
 		"candidates": []map[string]any{
 			{
@@ -175,10 +174,8 @@ func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, final
 }
 
 //nolint:unused // retained for native Gemini non-stream handling path.
-func buildGeminiUsage(finalPrompt, finalThinking, finalText string, promptTokens, outputTokens int) map[string]any {
-	if promptTokens <= 0 {
-		promptTokens = util.EstimateTokens(finalPrompt)
-	}
+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 {
diff --git a/internal/adapter/gemini/handler_stream_runtime.go b/internal/adapter/gemini/handler_stream_runtime.go
index b8d2701..e7c9b87 100644
--- a/internal/adapter/gemini/handler_stream_runtime.go
+++ b/internal/adapter/gemini/handler_stream_runtime.go
@@ -67,7 +67,6 @@ type geminiStreamRuntime struct {
 
 	thinking     strings.Builder
 	text         strings.Builder
-	promptTokens int
 	outputTokens int
 }
 
@@ -113,9 +112,6 @@ func (s *geminiStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Parse
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
-	if parsed.PromptTokens > 0 {
-		s.promptTokens = parsed.PromptTokens
-	}
 	if parsed.OutputTokens > 0 {
 		s.outputTokens = parsed.OutputTokens
 	}
@@ -202,6 +198,6 @@ func (s *geminiStreamRuntime) finalize() {
 			},
 		},
 		"modelVersion":  s.model,
-		"usageMetadata": buildGeminiUsage(s.finalPrompt, finalThinking, finalText, s.promptTokens, s.outputTokens),
+		"usageMetadata": buildGeminiUsage(s.finalPrompt, finalThinking, finalText, s.outputTokens),
 	})
 }
diff --git a/internal/adapter/gemini/handler_test.go b/internal/adapter/gemini/handler_test.go
index aa3ae46..b7aea1b 100644
--- a/internal/adapter/gemini/handler_test.go
+++ b/internal/adapter/gemini/handler_test.go
@@ -296,32 +296,6 @@ func TestGenerateContentOpenAIProxyErrorUsesGeminiEnvelope(t *testing.T) {
 	}
 }
 
-func TestBuildGeminiUsageOverridesPromptAndOutputTokensWhenProvided(t *testing.T) {
-	usage := buildGeminiUsage("prompt", "thinking", "answer", 11, 29)
-	if got, _ := usage["promptTokenCount"].(int); got != 11 {
-		t.Fatalf("expected promptTokenCount=11, got %#v", usage["promptTokenCount"])
-	}
-	if got, _ := usage["candidatesTokenCount"].(int); got != 29 {
-		t.Fatalf("expected candidatesTokenCount=29, got %#v", usage["candidatesTokenCount"])
-	}
-	if got, _ := usage["totalTokenCount"].(int); got != 40 {
-		t.Fatalf("expected totalTokenCount=40, got %#v", usage["totalTokenCount"])
-	}
-}
-
-func TestBuildGeminiUsageFallsBackToEstimateWhenNoUpstreamUsage(t *testing.T) {
-	usage := buildGeminiUsage("abcdef", "", "ghijkl", 0, 0)
-	if got, _ := usage["promptTokenCount"].(int); got <= 0 {
-		t.Fatalf("expected positive promptTokenCount estimate, got %#v", usage["promptTokenCount"])
-	}
-	if got, _ := usage["candidatesTokenCount"].(int); got <= 0 {
-		t.Fatalf("expected positive candidatesTokenCount estimate, got %#v", usage["candidatesTokenCount"])
-	}
-	if got, _ := usage["totalTokenCount"].(int); got <= 0 {
-		t.Fatalf("expected positive totalTokenCount estimate, got %#v", usage["totalTokenCount"])
-	}
-}
-
 func extractGeminiSSEFrames(t *testing.T, body string) []map[string]any {
 	t.Helper()
 	scanner := bufio.NewScanner(strings.NewReader(body))
diff --git a/internal/translatorcliproxy/bridge_test.go b/internal/translatorcliproxy/bridge_test.go
index 5f0979f..cdd9cf7 100644
--- a/internal/translatorcliproxy/bridge_test.go
+++ b/internal/translatorcliproxy/bridge_test.go
@@ -26,6 +26,26 @@ func TestFromOpenAINonStreamClaude(t *testing.T) {
 	}
 }
 
+func TestFromOpenAINonStreamClaudePreservesUsageFromOpenAI(t *testing.T) {
+	original := []byte(`{"model":"claude-sonnet-4-5","messages":[{"role":"user","content":"hi"}],"stream":false}`)
+	translatedReq := []byte(`{"model":"claude-sonnet-4-5","messages":[{"role":"user","content":"hi"}],"stream":false}`)
+	openaibody := []byte(`{"id":"chatcmpl_1","object":"chat.completion","created":1,"model":"claude-sonnet-4-5","choices":[{"index":0,"message":{"role":"assistant","content":"hello"},"finish_reason":"stop"}],"usage":{"prompt_tokens":11,"completion_tokens":29,"total_tokens":40}}`)
+	got := string(FromOpenAINonStream(sdktranslator.FormatClaude, "claude-sonnet-4-5", original, translatedReq, openaibody))
+	if !strings.Contains(got, `"input_tokens":11`) || !strings.Contains(got, `"output_tokens":29`) {
+		t.Fatalf("expected claude usage to preserve prompt/completion tokens, got: %s", got)
+	}
+}
+
+func TestFromOpenAINonStreamGeminiPreservesUsageFromOpenAI(t *testing.T) {
+	original := []byte(`{"contents":[{"role":"user","parts":[{"text":"hi"}]}]}`)
+	translatedReq := []byte(`{"model":"gemini-2.5-pro","messages":[{"role":"user","content":"hi"}],"stream":false}`)
+	openaibody := []byte(`{"id":"chatcmpl_1","object":"chat.completion","created":1,"model":"gemini-2.5-pro","choices":[{"index":0,"message":{"role":"assistant","content":"hello"},"finish_reason":"stop"}],"usage":{"prompt_tokens":11,"completion_tokens":29,"total_tokens":40}}`)
+	got := string(FromOpenAINonStream(sdktranslator.FormatGemini, "gemini-2.5-pro", original, translatedReq, openaibody))
+	if !strings.Contains(got, `"promptTokenCount":11`) || !strings.Contains(got, `"candidatesTokenCount":29`) || !strings.Contains(got, `"totalTokenCount":40`) {
+		t.Fatalf("expected gemini usageMetadata to preserve prompt/completion tokens, got: %s", got)
+	}
+}
+
 func TestParseFormatAliases(t *testing.T) {
 	cases := map[string]sdktranslator.Format{
 		"responses":        sdktranslator.FormatOpenAIResponse,
diff --git a/internal/translatorcliproxy/stream_writer.go b/internal/translatorcliproxy/stream_writer.go
index 07c4bcb..b1b8747 100644
--- a/internal/translatorcliproxy/stream_writer.go
+++ b/internal/translatorcliproxy/stream_writer.go
@@ -3,7 +3,9 @@ package translatorcliproxy
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"net/http"
+	"strings"
 
 	sdktranslator "github.com/router-for-me/CLIProxyAPI/v6/sdk/translator"
 )
@@ -77,7 +79,13 @@ func (w *OpenAIStreamTranslatorWriter) Write(p []byte) (int, error) {
 		if !bytes.HasPrefix(trimmed, []byte("data:")) {
 			continue
 		}
+		usage, hasUsage := extractOpenAIUsage(trimmed)
 		chunks := sdktranslator.TranslateStream(context.Background(), sdktranslator.FormatOpenAI, w.target, w.model, w.originalReq, w.translatedReq, trimmed, &w.param)
+		if hasUsage {
+			for i := range chunks {
+				chunks[i] = injectStreamUsageMetadata(chunks[i], w.target, usage)
+			}
+		}
 		for i := range chunks {
 			if len(chunks[i]) == 0 {
 				continue
@@ -118,3 +126,92 @@ func (w *OpenAIStreamTranslatorWriter) readOneLine() ([]byte, bool) {
 	w.lineBuf.Next(idx + 1)
 	return line, true
 }
+
+type openAIUsage struct {
+	PromptTokens     int
+	CompletionTokens int
+	TotalTokens      int
+}
+
+func extractOpenAIUsage(line []byte) (openAIUsage, bool) {
+	raw := strings.TrimSpace(strings.TrimPrefix(string(line), "data:"))
+	if raw == "" || raw == "[DONE]" {
+		return openAIUsage{}, false
+	}
+	var payload map[string]any
+	if err := json.Unmarshal([]byte(raw), &payload); err != nil {
+		return openAIUsage{}, false
+	}
+	usageObj, _ := payload["usage"].(map[string]any)
+	if usageObj == nil {
+		return openAIUsage{}, false
+	}
+	p := toInt(usageObj["prompt_tokens"])
+	c := toInt(usageObj["completion_tokens"])
+	t := toInt(usageObj["total_tokens"])
+	if p <= 0 && c <= 0 && t <= 0 {
+		return openAIUsage{}, false
+	}
+	if t <= 0 {
+		t = p + c
+	}
+	return openAIUsage{PromptTokens: p, CompletionTokens: c, TotalTokens: t}, true
+}
+
+func injectStreamUsageMetadata(chunk []byte, target sdktranslator.Format, usage openAIUsage) []byte {
+	if target != sdktranslator.FormatGemini {
+		return chunk
+	}
+	text := strings.TrimSpace(string(chunk))
+	if text == "" {
+		return chunk
+	}
+	var (
+		hasDataPrefix bool
+		jsonText      = text
+	)
+	if strings.HasPrefix(jsonText, "data:") {
+		hasDataPrefix = true
+		jsonText = strings.TrimSpace(strings.TrimPrefix(jsonText, "data:"))
+	}
+	if jsonText == "" || jsonText == "[DONE]" {
+		return chunk
+	}
+	obj := map[string]any{}
+	if err := json.Unmarshal([]byte(jsonText), &obj); err != nil {
+		return chunk
+	}
+	if _, ok := obj["candidates"]; !ok {
+		return chunk
+	}
+	obj["usageMetadata"] = map[string]any{
+		"promptTokenCount":     usage.PromptTokens,
+		"candidatesTokenCount": usage.CompletionTokens,
+		"totalTokenCount":      usage.TotalTokens,
+	}
+	b, err := json.Marshal(obj)
+	if err != nil {
+		return chunk
+	}
+	if hasDataPrefix {
+		return []byte("data: " + string(b))
+	}
+	return b
+}
+
+func toInt(v any) int {
+	switch x := v.(type) {
+	case int:
+		return x
+	case int32:
+		return int(x)
+	case int64:
+		return int(x)
+	case float64:
+		return int(x)
+	case float32:
+		return int(x)
+	default:
+		return 0
+	}
+}
diff --git a/internal/translatorcliproxy/stream_writer_test.go b/internal/translatorcliproxy/stream_writer_test.go
index 979d36e..77d2936 100644
--- a/internal/translatorcliproxy/stream_writer_test.go
+++ b/internal/translatorcliproxy/stream_writer_test.go
@@ -18,12 +18,16 @@ func TestOpenAIStreamTranslatorWriterClaude(t *testing.T) {
 	w.WriteHeader(200)
 	_, _ = w.Write([]byte("data: {\"id\":\"chatcmpl_1\",\"object\":\"chat.completion.chunk\",\"created\":1,\"model\":\"claude-sonnet-4-5\",\"choices\":[{\"index\":0,\"delta\":{\"role\":\"assistant\"},\"finish_reason\":null}]}\n\n"))
 	_, _ = w.Write([]byte("data: {\"id\":\"chatcmpl_1\",\"object\":\"chat.completion.chunk\",\"created\":1,\"model\":\"claude-sonnet-4-5\",\"choices\":[{\"index\":0,\"delta\":{\"content\":\"hi\"},\"finish_reason\":null}]}\n\n"))
+	_, _ = w.Write([]byte("data: {\"id\":\"chatcmpl_1\",\"object\":\"chat.completion.chunk\",\"created\":1,\"model\":\"claude-sonnet-4-5\",\"choices\":[{\"index\":0,\"delta\":{},\"finish_reason\":\"stop\"}],\"usage\":{\"prompt_tokens\":11,\"completion_tokens\":29,\"total_tokens\":40}}\n\n"))
 	_, _ = w.Write([]byte("data: [DONE]\n\n"))
 
 	body := rec.Body.String()
 	if !strings.Contains(body, "event: message_start") {
 		t.Fatalf("expected claude message_start event, got: %s", body)
 	}
+	if !strings.Contains(body, `"output_tokens":29`) {
+		t.Fatalf("expected claude stream usage to preserve output tokens, got: %s", body)
+	}
 }
 
 func TestOpenAIStreamTranslatorWriterGemini(t *testing.T) {
@@ -35,12 +39,16 @@ func TestOpenAIStreamTranslatorWriterGemini(t *testing.T) {
 	w.Header().Set("Content-Type", "text/event-stream")
 	w.WriteHeader(200)
 	_, _ = w.Write([]byte("data: {\"id\":\"chatcmpl_1\",\"object\":\"chat.completion.chunk\",\"created\":1,\"model\":\"gemini-2.5-pro\",\"choices\":[{\"index\":0,\"delta\":{\"content\":\"hi\"},\"finish_reason\":null}]}\n\n"))
+	_, _ = w.Write([]byte("data: {\"id\":\"chatcmpl_1\",\"object\":\"chat.completion.chunk\",\"created\":1,\"model\":\"gemini-2.5-pro\",\"choices\":[{\"index\":0,\"delta\":{},\"finish_reason\":\"stop\"}],\"usage\":{\"prompt_tokens\":11,\"completion_tokens\":29,\"total_tokens\":40}}\n\n"))
 	_, _ = w.Write([]byte("data: [DONE]\n\n"))
 
 	body := rec.Body.String()
 	if !strings.Contains(body, "candidates") {
 		t.Fatalf("expected gemini stream payload, got: %s", body)
 	}
+	if !strings.Contains(body, `"promptTokenCount":11`) || !strings.Contains(body, `"candidatesTokenCount":29`) {
+		t.Fatalf("expected gemini stream usageMetadata to preserve usage, got: %s", body)
+	}
 }
 
 func TestOpenAIStreamTranslatorWriterPreservesKeepAliveComment(t *testing.T) {