diff --git a/internal/registry/model_definitions_static_data.go b/internal/registry/model_definitions_static_data.go
index 182acdc5..45b1f133 100644
--- a/internal/registry/model_definitions_static_data.go
+++ b/internal/registry/model_definitions_static_data.go
@@ -716,6 +716,20 @@ func GetOpenAIModels() []*ModelInfo {
 			SupportedParameters: []string{"tools"},
 			Thinking:            &ThinkingSupport{Levels: []string{"low", "medium", "high", "xhigh"}},
 		},
+		{
+			ID:                  "gpt-5.3-codex",
+			Object:              "model",
+			Created:             1770307200,
+			OwnedBy:             "openai",
+			Type:                "openai",
+			Version:             "gpt-5.3",
+			DisplayName:         "GPT 5.3 Codex",
+			Description:         "Stable version of GPT 5.3 Codex, The best model for coding and agentic tasks across domains.",
+			ContextLength:       400000,
+			MaxCompletionTokens: 128000,
+			SupportedParameters: []string{"tools"},
+			Thinking:            &ThinkingSupport{Levels: []string{"low", "medium", "high", "xhigh"}},
+		},
 	}
 }
 
diff --git a/internal/runtime/executor/aistudio_executor.go b/internal/runtime/executor/aistudio_executor.go
index 317090d0..6faf028a 100644
--- a/internal/runtime/executor/aistudio_executor.go
+++ b/internal/runtime/executor/aistudio_executor.go
@@ -163,7 +163,7 @@ func (e *AIStudioExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth,
 	}
 	reporter.publish(ctx, parseGeminiUsage(wsResp.Body))
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, body.toFormat, opts.SourceFormat, req.Model, bytes.Clone(opts.OriginalRequest), bytes.Clone(translatedReq), bytes.Clone(wsResp.Body), &param)
+	out := sdktranslator.TranslateNonStream(ctx, body.toFormat, opts.SourceFormat, req.Model, opts.OriginalRequest, bytes.Clone(translatedReq), bytes.Clone(wsResp.Body), &param)
 	resp = cliproxyexecutor.Response{Payload: ensureColonSpacedJSON([]byte(out))}
 	return resp, nil
 }
@@ -279,7 +279,7 @@ func (e *AIStudioExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth
 					if detail, ok := parseGeminiStreamUsage(filtered); ok {
 						reporter.publish(ctx, detail)
 					}
-					lines := sdktranslator.TranslateStream(ctx, body.toFormat, opts.SourceFormat, req.Model, bytes.Clone(opts.OriginalRequest), translatedReq, bytes.Clone(filtered), &param)
+					lines := sdktranslator.TranslateStream(ctx, body.toFormat, opts.SourceFormat, req.Model, opts.OriginalRequest, translatedReq, bytes.Clone(filtered), &param)
 					for i := range lines {
 						out <- cliproxyexecutor.StreamChunk{Payload: ensureColonSpacedJSON([]byte(lines[i]))}
 					}
@@ -295,7 +295,7 @@ func (e *AIStudioExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth
 				if len(event.Payload) > 0 {
 					appendAPIResponseChunk(ctx, e.cfg, bytes.Clone(event.Payload))
 				}
-				lines := sdktranslator.TranslateStream(ctx, body.toFormat, opts.SourceFormat, req.Model, bytes.Clone(opts.OriginalRequest), translatedReq, bytes.Clone(event.Payload), &param)
+				lines := sdktranslator.TranslateStream(ctx, body.toFormat, opts.SourceFormat, req.Model, opts.OriginalRequest, translatedReq, bytes.Clone(event.Payload), &param)
 				for i := range lines {
 					out <- cliproxyexecutor.StreamChunk{Payload: ensureColonSpacedJSON([]byte(lines[i]))}
 				}
@@ -393,10 +393,11 @@ func (e *AIStudioExecutor) translateRequest(req cliproxyexecutor.Request, opts c
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, stream)
 	payload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), stream)
 	payload, err := thinking.ApplyThinking(payload, req.Model, from.String(), to.String(), e.Identifier())
diff --git a/internal/runtime/executor/antigravity_executor.go b/internal/runtime/executor/antigravity_executor.go
index 22062aba..7b38453f 100644
--- a/internal/runtime/executor/antigravity_executor.go
+++ b/internal/runtime/executor/antigravity_executor.go
@@ -133,10 +133,11 @@ func (e *AntigravityExecutor) Execute(ctx context.Context, auth *cliproxyauth.Au
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("antigravity")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -230,7 +231,7 @@ attemptLoop:
 
 			reporter.publish(ctx, parseAntigravityUsage(bodyBytes))
 			var param any
-			converted := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, bodyBytes, &param)
+			converted := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, bodyBytes, &param)
 			resp = cliproxyexecutor.Response{Payload: []byte(converted)}
 			reporter.ensurePublished(ctx)
 			return resp, nil
@@ -274,10 +275,11 @@ func (e *AntigravityExecutor) executeClaudeNonStream(ctx context.Context, auth *
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("antigravity")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -433,7 +435,7 @@ attemptLoop:
 
 			reporter.publish(ctx, parseAntigravityUsage(resp.Payload))
 			var param any
-			converted := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, resp.Payload, &param)
+			converted := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, resp.Payload, &param)
 			resp = cliproxyexecutor.Response{Payload: []byte(converted)}
 			reporter.ensurePublished(ctx)
 
@@ -665,10 +667,11 @@ func (e *AntigravityExecutor) ExecuteStream(ctx context.Context, auth *cliproxya
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("antigravity")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -800,12 +803,12 @@ attemptLoop:
 						reporter.publish(ctx, detail)
 					}
 
-					chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, bytes.Clone(payload), &param)
+					chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, bytes.Clone(payload), &param)
 					for i := range chunks {
 						out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
 					}
 				}
-				tail := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, []byte("[DONE]"), &param)
+				tail := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, []byte("[DONE]"), &param)
 				for i := range tail {
 					out <- cliproxyexecutor.StreamChunk{Payload: []byte(tail[i])}
 				}
diff --git a/internal/runtime/executor/claude_executor.go b/internal/runtime/executor/claude_executor.go
index 5b76d02a..694de1ef 100644
--- a/internal/runtime/executor/claude_executor.go
+++ b/internal/runtime/executor/claude_executor.go
@@ -100,10 +100,11 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	to := sdktranslator.FromString("claude")
 	// Use streaming translation to preserve function calling, except for claude.
 	stream := from != to
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, stream)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), stream)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -216,7 +217,7 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 		to,
 		from,
 		req.Model,
-		bytes.Clone(opts.OriginalRequest),
+		opts.OriginalRequest,
 		bodyForTranslation,
 		data,
 		&param,
@@ -240,10 +241,11 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	defer reporter.trackFailure(ctx, &err)
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("claude")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -381,7 +383,7 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 				to,
 				from,
 				req.Model,
-				bytes.Clone(opts.OriginalRequest),
+				opts.OriginalRequest,
 				bodyForTranslation,
 				bytes.Clone(line),
 				&param,
diff --git a/internal/runtime/executor/codex_executor.go b/internal/runtime/executor/codex_executor.go
index 09ce644e..3de2ba3b 100644
--- a/internal/runtime/executor/codex_executor.go
+++ b/internal/runtime/executor/codex_executor.go
@@ -88,10 +88,11 @@ func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("codex")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -176,7 +177,7 @@ func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 		}
 
 		var param any
-		out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(originalPayload), body, line, &param)
+		out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, originalPayload, body, line, &param)
 		resp = cliproxyexecutor.Response{Payload: []byte(out)}
 		return resp, nil
 	}
@@ -197,10 +198,11 @@ func (e *CodexExecutor) executeCompact(ctx context.Context, auth *cliproxyauth.A
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai-response")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -265,7 +267,7 @@ func (e *CodexExecutor) executeCompact(ctx context.Context, auth *cliproxyauth.A
 	reporter.publish(ctx, parseOpenAIUsage(data))
 	reporter.ensurePublished(ctx)
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(originalPayload), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, originalPayload, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -286,10 +288,11 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("codex")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -378,7 +381,7 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 				}
 			}
 
-			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(originalPayload), body, bytes.Clone(line), &param)
+			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, originalPayload, body, bytes.Clone(line), &param)
 			for i := range chunks {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
 			}
diff --git a/internal/runtime/executor/gemini_cli_executor.go b/internal/runtime/executor/gemini_cli_executor.go
index 16ff0158..a668c372 100644
--- a/internal/runtime/executor/gemini_cli_executor.go
+++ b/internal/runtime/executor/gemini_cli_executor.go
@@ -119,10 +119,11 @@ func (e *GeminiCLIExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini-cli")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	basePayload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -223,7 +224,7 @@ func (e *GeminiCLIExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth
 		if httpResp.StatusCode >= 200 && httpResp.StatusCode < 300 {
 			reporter.publish(ctx, parseGeminiCLIUsage(data))
 			var param any
-			out := sdktranslator.TranslateNonStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), payload, data, &param)
+			out := sdktranslator.TranslateNonStream(respCtx, to, from, attemptModel, opts.OriginalRequest, payload, data, &param)
 			resp = cliproxyexecutor.Response{Payload: []byte(out)}
 			return resp, nil
 		}
@@ -272,10 +273,11 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini-cli")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	basePayload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -399,14 +401,14 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 						reporter.publish(ctx, detail)
 					}
 					if bytes.HasPrefix(line, dataTag) {
-						segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone(line), &param)
+						segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, opts.OriginalRequest, reqBody, bytes.Clone(line), &param)
 						for i := range segments {
 							out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 						}
 					}
 				}
 
-				segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
+				segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, opts.OriginalRequest, reqBody, bytes.Clone([]byte("[DONE]")), &param)
 				for i := range segments {
 					out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 				}
@@ -428,12 +430,12 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 			appendAPIResponseChunk(ctx, e.cfg, data)
 			reporter.publish(ctx, parseGeminiCLIUsage(data))
 			var param any
-			segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, data, &param)
+			segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, opts.OriginalRequest, reqBody, data, &param)
 			for i := range segments {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 			}
 
-			segments = sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
+			segments = sdktranslator.TranslateStream(respCtx, to, from, attemptModel, opts.OriginalRequest, reqBody, bytes.Clone([]byte("[DONE]")), &param)
 			for i := range segments {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 			}
diff --git a/internal/runtime/executor/gemini_executor.go b/internal/runtime/executor/gemini_executor.go
index 8f729f5b..2d24d6ce 100644
--- a/internal/runtime/executor/gemini_executor.go
+++ b/internal/runtime/executor/gemini_executor.go
@@ -116,10 +116,11 @@ func (e *GeminiExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	// Official Gemini API via API key or OAuth bearer
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -203,7 +204,7 @@ func (e *GeminiExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	appendAPIResponseChunk(ctx, e.cfg, data)
 	reporter.publish(ctx, parseGeminiUsage(data))
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -222,10 +223,11 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -318,12 +320,12 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 			if detail, ok := parseGeminiStreamUsage(payload); ok {
 				reporter.publish(ctx, detail)
 			}
-			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(payload), &param)
+			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone(payload), &param)
 			for i := range lines {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 			}
 		}
-		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone([]byte("[DONE]")), &param)
+		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone([]byte("[DONE]")), &param)
 		for i := range lines {
 			out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 		}
diff --git a/internal/runtime/executor/gemini_vertex_executor.go b/internal/runtime/executor/gemini_vertex_executor.go
index 2db0e37c..be2fc238 100644
--- a/internal/runtime/executor/gemini_vertex_executor.go
+++ b/internal/runtime/executor/gemini_vertex_executor.go
@@ -318,10 +318,11 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 		from := opts.SourceFormat
 		to := sdktranslator.FromString("gemini")
 
-		originalPayload := bytes.Clone(req.Payload)
+		originalPayloadSource := req.Payload
 		if len(opts.OriginalRequest) > 0 {
-			originalPayload = bytes.Clone(opts.OriginalRequest)
+			originalPayloadSource = opts.OriginalRequest
 		}
+		originalPayload := bytes.Clone(originalPayloadSource)
 		originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 		body = sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -417,7 +418,7 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -432,10 +433,11 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
@@ -521,7 +523,7 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	appendAPIResponseChunk(ctx, e.cfg, data)
 	reporter.publish(ctx, parseGeminiUsage(data))
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -536,10 +538,11 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -632,12 +635,12 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 			if detail, ok := parseGeminiStreamUsage(line); ok {
 				reporter.publish(ctx, detail)
 			}
-			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
+			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone(line), &param)
 			for i := range lines {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 			}
 		}
-		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, []byte("[DONE]"), &param)
+		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, []byte("[DONE]"), &param)
 		for i := range lines {
 			out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 		}
@@ -660,10 +663,11 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
@@ -756,12 +760,12 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 			if detail, ok := parseGeminiStreamUsage(line); ok {
 				reporter.publish(ctx, detail)
 			}
-			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
+			lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone(line), &param)
 			for i := range lines {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 			}
 		}
-		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, []byte("[DONE]"), &param)
+		lines := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, []byte("[DONE]"), &param)
 		for i := range lines {
 			out <- cliproxyexecutor.StreamChunk{Payload: []byte(lines[i])}
 		}
diff --git a/internal/runtime/executor/iflow_executor.go b/internal/runtime/executor/iflow_executor.go
index 08a0a5af..abe9bdfa 100644
--- a/internal/runtime/executor/iflow_executor.go
+++ b/internal/runtime/executor/iflow_executor.go
@@ -87,10 +87,11 @@ func (e *IFlowExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -163,7 +164,7 @@ func (e *IFlowExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	var param any
 	// Note: TranslateNonStream uses req.Model (original with suffix) to preserve
 	// the original model name in the response for client compatibility.
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -189,10 +190,11 @@ func (e *IFlowExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -274,7 +276,7 @@ func (e *IFlowExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 			if detail, ok := parseOpenAIStreamUsage(line); ok {
 				reporter.publish(ctx, detail)
 			}
-			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
+			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone(line), &param)
 			for i := range chunks {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
 			}
diff --git a/internal/runtime/executor/openai_compat_executor.go b/internal/runtime/executor/openai_compat_executor.go
index ee61556e..3906948f 100644
--- a/internal/runtime/executor/openai_compat_executor.go
+++ b/internal/runtime/executor/openai_compat_executor.go
@@ -88,10 +88,11 @@ func (e *OpenAICompatExecutor) Execute(ctx context.Context, auth *cliproxyauth.A
 		to = sdktranslator.FromString("openai-response")
 		endpoint = "/responses/compact"
 	}
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, opts.Stream)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), opts.Stream)
 	requestedModel := payloadRequestedModel(opts, req.Model)
@@ -170,7 +171,7 @@ func (e *OpenAICompatExecutor) Execute(ctx context.Context, auth *cliproxyauth.A
 	reporter.ensurePublished(ctx)
 	// Translate response back to source format when needed
 	var param any
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, body, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, body, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -189,10 +190,11 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	requestedModel := payloadRequestedModel(opts, req.Model)
@@ -283,7 +285,7 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 
 			// OpenAI-compatible streams are SSE: lines typically prefixed with "data: ".
 			// Pass through translator; it yields one or more chunks for the target schema.
-			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), translated, bytes.Clone(line), &param)
+			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, bytes.Clone(line), &param)
 			for i := range chunks {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
 			}
diff --git a/internal/runtime/executor/qwen_executor.go b/internal/runtime/executor/qwen_executor.go
index 8df359e9..526c1389 100644
--- a/internal/runtime/executor/qwen_executor.go
+++ b/internal/runtime/executor/qwen_executor.go
@@ -81,10 +81,11 @@ func (e *QwenExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -150,7 +151,7 @@ func (e *QwenExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req
 	var param any
 	// Note: TranslateNonStream uses req.Model (original with suffix) to preserve
 	// the original model name in the response for client compatibility.
-	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
+	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, opts.OriginalRequest, body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
 	return resp, nil
 }
@@ -171,10 +172,11 @@ func (e *QwenExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Aut
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("openai")
-	originalPayload := bytes.Clone(req.Payload)
+	originalPayloadSource := req.Payload
 	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
+		originalPayloadSource = opts.OriginalRequest
 	}
+	originalPayload := bytes.Clone(originalPayloadSource)
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
@@ -253,12 +255,12 @@ func (e *QwenExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Aut
 			if detail, ok := parseOpenAIStreamUsage(line); ok {
 				reporter.publish(ctx, detail)
 			}
-			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
+			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone(line), &param)
 			for i := range chunks {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
 			}
 		}
-		doneChunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone([]byte("[DONE]")), &param)
+		doneChunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, body, bytes.Clone([]byte("[DONE]")), &param)
 		for i := range doneChunks {
 			out <- cliproxyexecutor.StreamChunk{Payload: []byte(doneChunks[i])}
 		}
diff --git a/internal/util/gemini_schema.go b/internal/util/gemini_schema.go
index b6b128d4..e74d1271 100644
--- a/internal/util/gemini_schema.go
+++ b/internal/util/gemini_schema.go
@@ -61,14 +61,20 @@ func cleanJSONSchema(jsonStr string, addPlaceholder bool) string {
 
 // removeKeywords removes all occurrences of specified keywords from the JSON schema.
 func removeKeywords(jsonStr string, keywords []string) string {
+	deletePaths := make([]string, 0)
+	pathsByField := findPathsByFields(jsonStr, keywords)
 	for _, key := range keywords {
-		for _, p := range findPaths(jsonStr, key) {
+		for _, p := range pathsByField[key] {
 			if isPropertyDefinition(trimSuffix(p, "."+key)) {
 				continue
 			}
-			jsonStr, _ = sjson.Delete(jsonStr, p)
+			deletePaths = append(deletePaths, p)
 		}
 	}
+	sortByDepth(deletePaths)
+	for _, p := range deletePaths {
+		jsonStr, _ = sjson.Delete(jsonStr, p)
+	}
 	return jsonStr
 }
 
@@ -235,8 +241,9 @@ var unsupportedConstraints = []string{
 }
 
 func moveConstraintsToDescription(jsonStr string) string {
+	pathsByField := findPathsByFields(jsonStr, unsupportedConstraints)
 	for _, key := range unsupportedConstraints {
-		for _, p := range findPaths(jsonStr, key) {
+		for _, p := range pathsByField[key] {
 			val := gjson.Get(jsonStr, p)
 			if !val.Exists() || val.IsObject() || val.IsArray() {
 				continue
@@ -424,14 +431,21 @@ func removeUnsupportedKeywords(jsonStr string) string {
 		"$schema", "$defs", "definitions", "const", "$ref", "additionalProperties",
 		"propertyNames", // Gemini doesn't support property name validation
 	)
+
+	deletePaths := make([]string, 0)
+	pathsByField := findPathsByFields(jsonStr, keywords)
 	for _, key := range keywords {
-		for _, p := range findPaths(jsonStr, key) {
+		for _, p := range pathsByField[key] {
 			if isPropertyDefinition(trimSuffix(p, "."+key)) {
 				continue
 			}
-			jsonStr, _ = sjson.Delete(jsonStr, p)
+			deletePaths = append(deletePaths, p)
 		}
 	}
+	sortByDepth(deletePaths)
+	for _, p := range deletePaths {
+		jsonStr, _ = sjson.Delete(jsonStr, p)
+	}
 	// Remove x-* extension fields (e.g., x-google-enum-descriptions) that are not supported by Gemini API
 	jsonStr = removeExtensionFields(jsonStr)
 	return jsonStr
@@ -581,6 +595,42 @@ func findPaths(jsonStr, field string) []string {
 	return paths
 }
 
+func findPathsByFields(jsonStr string, fields []string) map[string][]string {
+	set := make(map[string]struct{}, len(fields))
+	for _, field := range fields {
+		set[field] = struct{}{}
+	}
+	paths := make(map[string][]string, len(set))
+	walkForFields(gjson.Parse(jsonStr), "", set, paths)
+	return paths
+}
+
+func walkForFields(value gjson.Result, path string, fields map[string]struct{}, paths map[string][]string) {
+	switch value.Type {
+	case gjson.JSON:
+		value.ForEach(func(key, val gjson.Result) bool {
+			keyStr := key.String()
+			safeKey := escapeGJSONPathKey(keyStr)
+
+			var childPath string
+			if path == "" {
+				childPath = safeKey
+			} else {
+				childPath = path + "." + safeKey
+			}
+
+			if _, ok := fields[keyStr]; ok {
+				paths[keyStr] = append(paths[keyStr], childPath)
+			}
+
+			walkForFields(val, childPath, fields, paths)
+			return true
+		})
+	case gjson.String, gjson.Number, gjson.True, gjson.False, gjson.Null:
+		// Terminal types - no further traversal needed
+	}
+}
+
 func sortByDepth(paths []string) {
 	sort.Slice(paths, func(i, j int) bool { return len(paths[i]) > len(paths[j]) })
 }
diff --git a/sdk/api/handlers/handlers.go b/sdk/api/handlers/handlers.go
index fb26d4ff..624d5bc4 100644
--- a/sdk/api/handlers/handlers.go
+++ b/sdk/api/handlers/handlers.go
@@ -378,9 +378,13 @@ func (h *BaseAPIHandler) ExecuteWithAuthManager(ctx context.Context, handlerType
 	}
 	reqMeta := requestExecutionMetadata(ctx)
 	reqMeta[coreexecutor.RequestedModelMetadataKey] = normalizedModel
+	payload := rawJSON
+	if len(payload) == 0 {
+		payload = nil
+	}
 	req := coreexecutor.Request{
 		Model:   normalizedModel,
-		Payload: cloneBytes(rawJSON),
+		Payload: payload,
 	}
 	opts := coreexecutor.Options{
 		Stream:          false,
@@ -417,9 +421,13 @@ func (h *BaseAPIHandler) ExecuteCountWithAuthManager(ctx context.Context, handle
 	}
 	reqMeta := requestExecutionMetadata(ctx)
 	reqMeta[coreexecutor.RequestedModelMetadataKey] = normalizedModel
+	payload := rawJSON
+	if len(payload) == 0 {
+		payload = nil
+	}
 	req := coreexecutor.Request{
 		Model:   normalizedModel,
-		Payload: cloneBytes(rawJSON),
+		Payload: payload,
 	}
 	opts := coreexecutor.Options{
 		Stream:          false,
@@ -459,9 +467,13 @@ func (h *BaseAPIHandler) ExecuteStreamWithAuthManager(ctx context.Context, handl
 	}
 	reqMeta := requestExecutionMetadata(ctx)
 	reqMeta[coreexecutor.RequestedModelMetadataKey] = normalizedModel
+	payload := rawJSON
+	if len(payload) == 0 {
+		payload = nil
+	}
 	req := coreexecutor.Request{
 		Model:   normalizedModel,
-		Payload: cloneBytes(rawJSON),
+		Payload: payload,
 	}
 	opts := coreexecutor.Options{
 		Stream:          true,