diff --git a/backend/internal/handler/gateway_handler.go b/backend/internal/handler/gateway_handler.go
index eb5c4a42..79bed8b9 100644
--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -154,7 +154,8 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 
 	setOpsRequestContext(c, "", false)
 
-	parsedReq, err := service.ParseGatewayRequest(body, domain.PlatformAnthropic)
+	bodyRef := service.NewRequestBodyRef(body)
+	parsedReq, err := service.ParseGatewayRequest(bodyRef, domain.PlatformAnthropic)
 	if err != nil {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
@@ -746,11 +747,11 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 			// 应用渠道模型映射到请求
 			if channelMapping.Mapped {
 				parsedReq.Model = channelMapping.MappedModel
-				parsedReq.Body = h.gatewayService.ReplaceModelInBody(parsedReq.Body, channelMapping.MappedModel)
+				parsedReq.Body.Replace(h.gatewayService.ReplaceModelInBody(parsedReq.Body.Bytes(), channelMapping.MappedModel))
 			}
 			// Bedrock CC 兼容：渠道模型映射后，清理 Anthropic API 专有字段、注入 Bedrock 必需字段
-			parsedReq.Body = h.gatewayService.ApplyBedrockCCCompat(c.Request.Context(), parsedReq.Body, parsedReq.Model, account, apiKey.GroupID)
-			body = parsedReq.Body
+			parsedReq.Body.Replace(h.gatewayService.ApplyBedrockCCCompat(c.Request.Context(), parsedReq.Body.Bytes(), parsedReq.Model, account, apiKey.GroupID))
+			body = parsedReq.Body.Bytes()
 
 			// 转发请求 - 根据账号平台分流
 			c.Set("parsed_request", parsedReq)
@@ -1683,7 +1684,8 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 
 	setOpsRequestContext(c, "", false)
 
-	parsedReq, err := service.ParseGatewayRequest(body, domain.PlatformAnthropic)
+	bodyRef := service.NewRequestBodyRef(body)
+	parsedReq, err := service.ParseGatewayRequest(bodyRef, domain.PlatformAnthropic)
 	if err != nil {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
diff --git a/backend/internal/handler/gateway_handler_chat_completions.go b/backend/internal/handler/gateway_handler_chat_completions.go
index daf6e6ea..719700aa 100644
--- a/backend/internal/handler/gateway_handler_chat_completions.go
+++ b/backend/internal/handler/gateway_handler_chat_completions.go
@@ -151,9 +151,10 @@ func (h *GatewayHandler) ChatCompletions(c *gin.Context) {
 	}
 
 	// Parse request for session hash
-	parsedReq, _ := service.ParseGatewayRequest(body, "chat_completions")
+	bodyRef := service.NewRequestBodyRef(body)
+	parsedReq, _ := service.ParseGatewayRequest(bodyRef, "chat_completions")
 	if parsedReq == nil {
-		parsedReq = &service.ParsedRequest{Model: reqModel, Stream: reqStream, Body: body}
+		parsedReq = &service.ParsedRequest{Model: reqModel, Stream: reqStream, Body: bodyRef}
 	}
 	parsedReq.SessionContext = &service.SessionContext{
 		ClientIP:  ip.GetClientIP(c),
diff --git a/backend/internal/handler/gateway_handler_responses.go b/backend/internal/handler/gateway_handler_responses.go
index f57b9989..49f80d19 100644
--- a/backend/internal/handler/gateway_handler_responses.go
+++ b/backend/internal/handler/gateway_handler_responses.go
@@ -156,9 +156,10 @@ func (h *GatewayHandler) Responses(c *gin.Context) {
 	}
 
 	// Parse request for session hash
-	parsedReq, _ := service.ParseGatewayRequest(body, "responses")
+	bodyRef := service.NewRequestBodyRef(body)
+	parsedReq, _ := service.ParseGatewayRequest(bodyRef, "responses")
 	if parsedReq == nil {
-		parsedReq = &service.ParsedRequest{Model: reqModel, Stream: reqStream, Body: body}
+		parsedReq = &service.ParsedRequest{Model: reqModel, Stream: reqStream, Body: bodyRef}
 	}
 	parsedReq.SessionContext = &service.SessionContext{
 		ClientIP:  ip.GetClientIP(c),
diff --git a/backend/internal/handler/gemini_v1beta_handler.go b/backend/internal/handler/gemini_v1beta_handler.go
index 0b33ca3e..5d8e6fa8 100644
--- a/backend/internal/handler/gemini_v1beta_handler.go
+++ b/backend/internal/handler/gemini_v1beta_handler.go
@@ -262,7 +262,7 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 	sessionHash := extractGeminiCLISessionHash(c, body)
 	if sessionHash == "" {
 		// Fallback: 使用通用的会话哈希生成逻辑（适用于其他客户端）
-		parsedReq, _ := service.ParseGatewayRequest(body, domain.PlatformGemini)
+		parsedReq, _ := service.ParseGatewayRequest(service.NewRequestBodyRef(body), domain.PlatformGemini)
 		if parsedReq != nil {
 			parsedReq.SessionContext = &service.SessionContext{
 				ClientIP:  ip.GetClientIP(c),
diff --git a/backend/internal/service/gateway_anthropic_apikey_passthrough_test.go b/backend/internal/service/gateway_anthropic_apikey_passthrough_test.go
index 9062c517..a67a3dc2 100644
--- a/backend/internal/service/gateway_anthropic_apikey_passthrough_test.go
+++ b/backend/internal/service/gateway_anthropic_apikey_passthrough_test.go
@@ -112,7 +112,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_ForwardStreamPreservesBodyAnd
 
 	body := []byte(`{"model":"claude-3-7-sonnet-20250219","stream":true,"system":[{"type":"text","text":"x-anthropic-billing-header keep"}],"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
 	parsed := &ParsedRequest{
-		Body:   body,
+		Body:   NewRequestBodyRef(body),
 		Model:  "claude-3-7-sonnet-20250219",
 		Stream: true,
 	}
@@ -202,7 +202,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_ForwardCountTokensPreservesBo
 
 	body := []byte(`{"model":"claude-3-5-sonnet-latest","messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}],"thinking":{"type":"enabled"}}`)
 	parsed := &ParsedRequest{
-		Body:  body,
+		Body:  NewRequestBodyRef(body),
 		Model: "claude-3-5-sonnet-latest",
 	}
 
@@ -344,7 +344,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_ModelMappingEdgeCases(t *test
 
 			body := []byte(`{"model":"` + tt.model + `","messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
 			parsed := &ParsedRequest{
-				Body:  body,
+				Body:  NewRequestBodyRef(body),
 				Model: tt.model,
 			}
 
@@ -429,7 +429,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_ModelMappingPreservesOtherFie
 	// 包含复杂字段的请求体：system、thinking、messages
 	body := []byte(`{"model":"claude-sonnet-4-20250514","system":[{"type":"text","text":"You are a helpful assistant."}],"messages":[{"role":"user","content":[{"type":"text","text":"hello world"}]}],"thinking":{"type":"enabled","budget_tokens":5000},"max_tokens":1024}`)
 	parsed := &ParsedRequest{
-		Body:  body,
+		Body:  NewRequestBodyRef(body),
 		Model: "claude-sonnet-4-20250514",
 	}
 
@@ -485,7 +485,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_CountTokensFiltersGenerationF
 
 	body := []byte(`{"model":"claude-sonnet-4-20250514","system":[{"type":"text","text":"sys"}],"messages":[{"role":"user","content":"hello"}],"tools":[{"name":"tool","input_schema":{"type":"object"}}],"temperature":0.7,"top_p":0.9,"top_k":40,"stream":true,"stop_sequences":["END"],"max_tokens":1024,"thinking":{"type":"enabled","budget_tokens":5000}}`)
 	parsed := &ParsedRequest{
-		Body:  body,
+		Body:  NewRequestBodyRef(body),
 		Model: "claude-sonnet-4-20250514",
 	}
 
@@ -547,7 +547,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_EmptyModelSkipsMapping(t *tes
 
 	body := []byte(`{"messages":[{"role":"user","content":"hello"}]}`)
 	parsed := &ParsedRequest{
-		Body:  body,
+		Body:  NewRequestBodyRef(body),
 		Model: "", // 空模型
 	}
 
@@ -636,7 +636,7 @@ func TestGatewayService_AnthropicAPIKeyPassthrough_CountTokens404PassthroughNotE
 			c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages/count_tokens", nil)
 
 			body := []byte(`{"model":"claude-sonnet-4-5-20250929","messages":[{"role":"user","content":"hi"}]}`)
-			parsed := &ParsedRequest{Body: body, Model: "claude-sonnet-4-5-20250929"}
+			parsed := &ParsedRequest{Body: NewRequestBodyRef(body), Model: "claude-sonnet-4-5-20250929"}
 
 			upstream := &anthropicHTTPUpstreamRecorder{
 				resp: &http.Response{
@@ -767,7 +767,7 @@ func TestGatewayService_AnthropicOAuth_ForwardPreservesBillingHeaderSystemBlock(
 			c, _ := gin.CreateTestContext(rec)
 			c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
 
-			parsed, err := ParseGatewayRequest([]byte(tt.body), PlatformAnthropic)
+			parsed, err := ParseGatewayRequest(NewRequestBodyRef([]byte(tt.body)), PlatformAnthropic)
 			require.NoError(t, err)
 
 			upstream := &anthropicHTTPUpstreamRecorder{
diff --git a/backend/internal/service/gateway_request.go b/backend/internal/service/gateway_request.go
index 91f7601c..819bb0a8 100644
--- a/backend/internal/service/gateway_request.go
+++ b/backend/internal/service/gateway_request.go
@@ -51,6 +51,35 @@ type SessionContext struct {
 	APIKeyID  int64
 }
 
+type RequestBodyRef struct {
+	data []byte
+}
+
+func NewRequestBodyRef(data []byte) *RequestBodyRef {
+	return &RequestBodyRef{data: data}
+}
+
+func (b *RequestBodyRef) Bytes() []byte {
+	if b == nil {
+		return nil
+	}
+	return b.data
+}
+
+func (b *RequestBodyRef) Len() int {
+	if b == nil {
+		return 0
+	}
+	return len(b.data)
+}
+
+func (b *RequestBodyRef) Replace(data []byte) {
+	if b == nil {
+		return
+	}
+	b.data = data
+}
+
 // ParsedRequest 保存网关请求的预解析结果
 //
 // 性能优化说明：
@@ -64,7 +93,7 @@ type SessionContext struct {
 // 2. 将解析结果 ParsedRequest 传递给 Service 层
 // 3. 避免重复 json.Unmarshal，减少 CPU 和内存开销
 type ParsedRequest struct {
-	Body            []byte          // 原始请求体（保留用于转发）
+	Body            *RequestBodyRef // 原始请求体引用（保留用于转发）
 	Model           string          // 请求的模型名称
 	Stream          bool            // 是否为流式请求
 	MetadataUserID  string          // metadata.user_id（用于会话亲和）
@@ -130,17 +159,18 @@ func normalizeSessionUserAgentFallback(raw string) string {
 // ParseGatewayRequest 解析网关请求体并返回结构化结果。
 // protocol 指定请求协议格式（domain.PlatformAnthropic / domain.PlatformGemini），
 // 不同协议使用不同的 system/messages 字段名。
-func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
+func ParseGatewayRequest(body *RequestBodyRef, protocol string) (*ParsedRequest, error) {
+	bodyBytes := body.Bytes()
 	// 保持与旧实现一致：请求体必须是合法 JSON。
 	// 注意：gjson.GetBytes 对非法 JSON 不会报错，因此需要显式校验。
-	if !gjson.ValidBytes(body) {
+	if !gjson.ValidBytes(bodyBytes) {
 		return nil, fmt.Errorf("invalid json")
 	}
 
 	// 性能：
 	// - gjson.GetBytes 会把匹配的 Raw/Str 安全复制成 string（对于巨大 messages 会产生额外拷贝）。
 	// - 这里将 body 通过 unsafe 零拷贝视为 string，仅在本函数内使用，且 body 不会被修改。
-	jsonStr := *(*string)(unsafe.Pointer(&body))
+	jsonStr := *(*string)(unsafe.Pointer(&bodyBytes))
 
 	parsed := &ParsedRequest{
 		Body: body,
@@ -197,7 +227,7 @@ func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
 		// Gemini 原生格式: systemInstruction.parts / contents
 		if sysParts := gjson.Get(jsonStr, "systemInstruction.parts"); sysParts.Exists() && sysParts.IsArray() {
 			var parts []any
-			if err := json.Unmarshal(sliceRawFromBody(body, sysParts), &parts); err != nil {
+			if err := json.Unmarshal(sliceRawFromBody(bodyBytes, sysParts), &parts); err != nil {
 				return nil, err
 			}
 			parsed.System = parts
@@ -205,7 +235,7 @@ func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
 
 		if contents := gjson.Get(jsonStr, "contents"); contents.Exists() && contents.IsArray() {
 			var msgs []any
-			if err := json.Unmarshal(sliceRawFromBody(body, contents), &msgs); err != nil {
+			if err := json.Unmarshal(sliceRawFromBody(bodyBytes, contents), &msgs); err != nil {
 				return nil, err
 			}
 			parsed.Messages = msgs
@@ -224,7 +254,7 @@ func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
 				parsed.System = sys.String()
 			default:
 				var system any
-				if err := json.Unmarshal(sliceRawFromBody(body, sys), &system); err != nil {
+				if err := json.Unmarshal(sliceRawFromBody(bodyBytes, sys), &system); err != nil {
 					return nil, err
 				}
 				parsed.System = system
@@ -233,7 +263,7 @@ func ParseGatewayRequest(body []byte, protocol string) (*ParsedRequest, error) {
 
 		if msgs := gjson.Get(jsonStr, "messages"); msgs.Exists() && msgs.IsArray() {
 			var messages []any
-			if err := json.Unmarshal(sliceRawFromBody(body, msgs), &messages); err != nil {
+			if err := json.Unmarshal(sliceRawFromBody(bodyBytes, msgs), &messages); err != nil {
 				return nil, err
 			}
 			parsed.Messages = messages
diff --git a/backend/internal/service/gateway_request_test.go b/backend/internal/service/gateway_request_test.go
index 045dc66c..d415b871 100644
--- a/backend/internal/service/gateway_request_test.go
+++ b/backend/internal/service/gateway_request_test.go
@@ -14,7 +14,7 @@ import (
 
 func TestParseGatewayRequest(t *testing.T) {
 	body := []byte(`{"model":"claude-3-7-sonnet","stream":true,"metadata":{"user_id":"session_123e4567-e89b-12d3-a456-426614174000"},"system":[{"type":"text","text":"hello","cache_control":{"type":"ephemeral"}}],"messages":[{"content":"hi"}]}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	require.Equal(t, "claude-3-7-sonnet", parsed.Model)
 	require.True(t, parsed.Stream)
@@ -27,7 +27,7 @@ func TestParseGatewayRequest(t *testing.T) {
 
 func TestParseGatewayRequest_ThinkingEnabled(t *testing.T) {
 	body := []byte(`{"model":"claude-sonnet-4-5","thinking":{"type":"enabled"},"messages":[{"content":"hi"}]}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	require.Equal(t, "claude-sonnet-4-5", parsed.Model)
 	require.True(t, parsed.ThinkingEnabled)
@@ -35,7 +35,7 @@ func TestParseGatewayRequest_ThinkingEnabled(t *testing.T) {
 
 func TestParseGatewayRequest_ThinkingAdaptiveEnabled(t *testing.T) {
 	body := []byte(`{"model":"claude-sonnet-4-5","thinking":{"type":"adaptive"},"messages":[{"content":"hi"}]}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	require.Equal(t, "claude-sonnet-4-5", parsed.Model)
 	require.True(t, parsed.ThinkingEnabled)
@@ -43,21 +43,21 @@ func TestParseGatewayRequest_ThinkingAdaptiveEnabled(t *testing.T) {
 
 func TestParseGatewayRequest_MaxTokens(t *testing.T) {
 	body := []byte(`{"model":"claude-haiku-4-5","max_tokens":1}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	require.Equal(t, 1, parsed.MaxTokens)
 }
 
 func TestParseGatewayRequest_MaxTokensNonIntegralIgnored(t *testing.T) {
 	body := []byte(`{"model":"claude-haiku-4-5","max_tokens":1.5}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	require.Equal(t, 0, parsed.MaxTokens)
 }
 
 func TestParseGatewayRequest_SystemNull(t *testing.T) {
 	body := []byte(`{"model":"claude-3","system":null}`)
-	parsed, err := ParseGatewayRequest(body, "")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.NoError(t, err)
 	// 显式传入 system:null 也应视为“字段已存在”，避免默认 system 被注入。
 	require.True(t, parsed.HasSystem)
@@ -66,13 +66,13 @@ func TestParseGatewayRequest_SystemNull(t *testing.T) {
 
 func TestParseGatewayRequest_InvalidModelType(t *testing.T) {
 	body := []byte(`{"model":123}`)
-	_, err := ParseGatewayRequest(body, "")
+	_, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.Error(t, err)
 }
 
 func TestParseGatewayRequest_InvalidStreamType(t *testing.T) {
 	body := []byte(`{"stream":"true"}`)
-	_, err := ParseGatewayRequest(body, "")
+	_, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 	require.Error(t, err)
 }
 
@@ -86,7 +86,7 @@ func TestParseGatewayRequest_GeminiContents(t *testing.T) {
 			{"role": "user", "parts": [{"text": "How are you?"}]}
 		]
 	}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.Len(t, parsed.Messages, 3, "should parse contents as Messages")
 	require.False(t, parsed.HasSystem, "Gemini format should not set HasSystem")
@@ -102,7 +102,7 @@ func TestParseGatewayRequest_GeminiSystemInstruction(t *testing.T) {
 			{"role": "user", "parts": [{"text": "Hello"}]}
 		]
 	}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.NotNil(t, parsed.System, "should parse systemInstruction.parts as System")
 	parts, ok := parsed.System.([]any)
@@ -119,7 +119,7 @@ func TestParseGatewayRequest_GeminiWithModel(t *testing.T) {
 		"model": "gemini-2.5-pro",
 		"contents": [{"role": "user", "parts": [{"text": "test"}]}]
 	}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.Equal(t, "gemini-2.5-pro", parsed.Model)
 	require.Len(t, parsed.Messages, 1)
@@ -132,7 +132,7 @@ func TestParseGatewayRequest_GeminiIgnoresAnthropicFields(t *testing.T) {
 		"messages": [{"role": "user", "content": "ignored"}],
 		"contents": [{"role": "user", "parts": [{"text": "real content"}]}]
 	}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.False(t, parsed.HasSystem, "Gemini protocol should not parse Anthropic system field")
 	require.Nil(t, parsed.System, "no systemInstruction = nil System")
@@ -141,14 +141,14 @@ func TestParseGatewayRequest_GeminiIgnoresAnthropicFields(t *testing.T) {
 
 func TestParseGatewayRequest_GeminiEmptyContents(t *testing.T) {
 	body := []byte(`{"contents": []}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.Empty(t, parsed.Messages)
 }
 
 func TestParseGatewayRequest_GeminiNoContents(t *testing.T) {
 	body := []byte(`{"model": "gemini-2.5-flash"}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformGemini)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformGemini)
 	require.NoError(t, err)
 	require.Nil(t, parsed.Messages)
 	require.Equal(t, "gemini-2.5-flash", parsed.Model)
@@ -162,7 +162,7 @@ func TestParseGatewayRequest_AnthropicIgnoresGeminiFields(t *testing.T) {
 		"contents": [{"role": "user", "parts": [{"text": "ignored"}]}],
 		"systemInstruction": {"parts": [{"text": "ignored"}]}
 	}`)
-	parsed, err := ParseGatewayRequest(body, domain.PlatformAnthropic)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformAnthropic)
 	require.NoError(t, err)
 	require.True(t, parsed.HasSystem)
 	require.Equal(t, "real system", parsed.System)
@@ -897,7 +897,7 @@ func TestParseGatewayRequest_TypeValidation(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := ParseGatewayRequest([]byte(tt.body), "")
+			_, err := ParseGatewayRequest(NewRequestBodyRef([]byte(tt.body)), "")
 			if tt.wantErr {
 				require.Error(t, err)
 				if tt.errSubstr != "" {
@@ -959,7 +959,7 @@ func TestParseGatewayRequest_OptionalFieldsMissing(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			parsed, err := ParseGatewayRequest([]byte(tt.body), "")
+			parsed, err := ParseGatewayRequest(NewRequestBodyRef([]byte(tt.body)), "")
 			require.NoError(t, err)
 
 			require.Equal(t, tt.wantModel, parsed.Model)
@@ -1023,7 +1023,7 @@ func TestParseGatewayRequest_MaxTokensBoundary(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			parsed, err := ParseGatewayRequest([]byte(tt.body), "")
+			parsed, err := ParseGatewayRequest(NewRequestBodyRef([]byte(tt.body)), "")
 			if tt.wantErr {
 				require.Error(t, err)
 				return
@@ -1040,7 +1040,7 @@ func TestParseGatewayRequest_MaxTokensBoundary(t *testing.T) {
 // 核心路径：先 Unmarshal 到 map[string]any，再逐字段提取。
 func parseGatewayRequestOld(body []byte, protocol string) (*ParsedRequest, error) {
 	parsed := &ParsedRequest{
-		Body: body,
+		Body: NewRequestBodyRef(body),
 	}
 
 	var req map[string]any
@@ -1151,7 +1151,7 @@ func BenchmarkParseGatewayRequest_New_Small(b *testing.B) {
 	b.SetBytes(int64(len(data)))
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		_, _ = ParseGatewayRequest(data, "")
+		_, _ = ParseGatewayRequest(NewRequestBodyRef(data), "")
 	}
 }
 
@@ -1203,7 +1203,7 @@ func TestParseGatewayRequest_OutputEffort(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			parsed, err := ParseGatewayRequest([]byte(tt.body), "")
+			parsed, err := ParseGatewayRequest(NewRequestBodyRef([]byte(tt.body)), "")
 			require.NoError(t, err)
 			require.Equal(t, tt.wantEffort, parsed.OutputEffort)
 		})
@@ -1245,6 +1245,6 @@ func BenchmarkParseGatewayRequest_New_Large(b *testing.B) {
 	b.SetBytes(int64(len(data)))
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		_, _ = ParseGatewayRequest(data, "")
+		_, _ = ParseGatewayRequest(NewRequestBodyRef(data), "")
 	}
 }
diff --git a/backend/internal/service/gateway_service.go b/backend/internal/service/gateway_service.go
index f807f3ec..8f55bf13 100644
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -4400,12 +4400,12 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 	}
 
 	// Web Search 模拟：纯 web_search 请求时，直接调用搜索 API 构造响应
-	if account != nil && s.shouldEmulateWebSearch(ctx, account, parsed.GroupID, parsed.Body) {
+	if account != nil && s.shouldEmulateWebSearch(ctx, account, parsed.GroupID, parsed.Body.Bytes()) {
 		return s.handleWebSearchEmulation(ctx, c, account, parsed)
 	}
 
 	if account != nil && account.IsAnthropicAPIKeyPassthroughEnabled() {
-		passthroughBody := parsed.Body
+		passthroughBody := parsed.Body.Bytes()
 		passthroughModel := parsed.Model
 		if passthroughModel != "" {
 			if mappedModel := account.GetMappedModel(passthroughModel); mappedModel != passthroughModel {
@@ -4441,7 +4441,7 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 		c.Set(betaPolicyFilterSetKey, filterSet)
 	}
 
-	body := parsed.Body
+	body := parsed.Body.Bytes()
 	reqModel := parsed.Model
 	reqStream := parsed.Stream
 	originalModel := reqModel
@@ -5735,7 +5735,7 @@ func (s *GatewayService) forwardBedrock(
 ) (*ForwardResult, error) {
 	reqModel := parsed.Model
 	reqStream := parsed.Stream
-	body := parsed.Body
+	body := parsed.Body.Bytes()
 
 	region := bedrockRuntimeRegion(account)
 	mappedModel, ok := ResolveBedrockModelID(account, reqModel)
@@ -9172,7 +9172,7 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 	}
 
 	if account != nil && account.IsAnthropicAPIKeyPassthroughEnabled() {
-		passthroughBody := parsed.Body
+		passthroughBody := parsed.Body.Bytes()
 		if reqModel := parsed.Model; reqModel != "" {
 			if mappedModel := account.GetMappedModel(reqModel); mappedModel != reqModel {
 				passthroughBody = s.replaceModelInBody(passthroughBody, mappedModel)
@@ -9188,7 +9188,7 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 		return nil
 	}
 
-	body := parsed.Body
+	body := parsed.Body.Bytes()
 	reqModel := parsed.Model
 
 	// Pre-filter: strip empty text blocks to prevent upstream 400.
diff --git a/backend/internal/service/gateway_service_benchmark_test.go b/backend/internal/service/gateway_service_benchmark_test.go
index c9c4d3dd..5637680b 100644
--- a/backend/internal/service/gateway_service_benchmark_test.go
+++ b/backend/internal/service/gateway_service_benchmark_test.go
@@ -14,7 +14,7 @@ func BenchmarkGenerateSessionHash_Metadata(b *testing.B) {
 
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
-		parsed, err := ParseGatewayRequest(body, "")
+		parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "")
 		if err != nil {
 			b.Fatalf("解析请求失败: %v", err)
 		}
diff --git a/backend/internal/service/gateway_websearch_emulation.go b/backend/internal/service/gateway_websearch_emulation.go
index a42b5585..2f9c8e0c 100644
--- a/backend/internal/service/gateway_websearch_emulation.go
+++ b/backend/internal/service/gateway_websearch_emulation.go
@@ -150,7 +150,7 @@ func (s *GatewayService) handleWebSearchEmulation(
 		parsed.OnUpstreamAccepted()
 	}
 
-	query := extractSearchQueryFromBody(parsed.Body)
+	query := extractSearchQueryFromBody(parsed.Body.Bytes())
 	if query == "" {
 		return nil, fmt.Errorf("web search emulation: no query found in messages")
 	}
diff --git a/backend/internal/service/generate_session_hash_test.go b/backend/internal/service/generate_session_hash_test.go
index 39679c3d..8f3258b7 100644
--- a/backend/internal/service/generate_session_hash_test.go
+++ b/backend/internal/service/generate_session_hash_test.go
@@ -1198,7 +1198,7 @@ func TestGenerateSessionHash_GeminiMultiTurnHashNotSticky(t *testing.T) {
 
 	hashes := make([]string, 3)
 	for i, body := range [][]byte{round1Body, round2Body, round3Body} {
-		parsed, err := ParseGatewayRequest(body, "gemini")
+		parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "gemini")
 		require.NoError(t, err)
 		parsed.SessionContext = ctx
 		hashes[i] = svc.GenerateSessionHash(parsed)
@@ -1211,7 +1211,7 @@ func TestGenerateSessionHash_GeminiMultiTurnHashNotSticky(t *testing.T) {
 	require.NotEqual(t, hashes[0], hashes[2], "round 1 vs 3 hash should differ")
 
 	// 同一轮重试应产生相同 hash
-	parsed1Again, err := ParseGatewayRequest(round2Body, "gemini")
+	parsed1Again, err := ParseGatewayRequest(NewRequestBodyRef(round2Body), "gemini")
 	require.NoError(t, err)
 	parsed1Again.SessionContext = ctx
 	h2Again := svc.GenerateSessionHash(parsed1Again)
@@ -1234,7 +1234,7 @@ func TestGenerateSessionHash_GeminiEndToEnd(t *testing.T) {
 		]
 	}`)
 
-	parsed, err := ParseGatewayRequest(body, "gemini")
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), "gemini")
 	require.NoError(t, err)
 	parsed.SessionContext = &SessionContext{
 		ClientIP:  "10.0.0.1",
@@ -1246,7 +1246,7 @@ func TestGenerateSessionHash_GeminiEndToEnd(t *testing.T) {
 	require.NotEmpty(t, h, "end-to-end Gemini flow should produce a hash")
 
 	// 同一请求再次解析应产生相同 hash
-	parsed2, err := ParseGatewayRequest(body, "gemini")
+	parsed2, err := ParseGatewayRequest(NewRequestBodyRef(body), "gemini")
 	require.NoError(t, err)
 	parsed2.SessionContext = &SessionContext{
 		ClientIP:  "10.0.0.1",
@@ -1258,7 +1258,7 @@ func TestGenerateSessionHash_GeminiEndToEnd(t *testing.T) {
 	require.Equal(t, h, h2, "same request should produce same hash")
 
 	// 不同用户发送相同请求应产生不同 hash
-	parsed3, err := ParseGatewayRequest(body, "gemini")
+	parsed3, err := ParseGatewayRequest(NewRequestBodyRef(body), "gemini")
 	require.NoError(t, err)
 	parsed3.SessionContext = &SessionContext{
 		ClientIP:  "10.0.0.2",