feat(xai): normalize xAI input reasoning items and enhance test cases

- Added `normalizeXAIInputReasoningItems` to clean up `input` reasoning items, removing null `content` and `encrypted_content` fields.
- Updated `xai_executor` test cases to validate input normalization and reasoning item handling.

internal/runtime/executor/xai_executor.go

@@ -500,6 +500,7 @@ func (e *XAIExecutor) prepareResponsesRequest(ctx context.Context, req cliproxye
 	body, _ = sjson.DeleteBytes(body, "safety_identifier")
 	body, _ = sjson.DeleteBytes(body, "stream_options")
 	body = normalizeXAITools(body)
+	body = normalizeXAIInputReasoningItems(body)
 	body = normalizeCodexInstructions(body)
 	body = sanitizeXAIResponsesBody(body, baseModel)
 
@@ -704,6 +705,37 @@ func normalizeXAITools(body []byte) []byte {
 	return updated
 }
 
+func normalizeXAIInputReasoningItems(body []byte) []byte {
+	input := gjson.GetBytes(body, "input")
+	if !input.Exists() || !input.IsArray() {
+		return body
+	}
+
+	updated := body
+	for i, item := range input.Array() {
+		if item.Get("type").String() != "reasoning" {
+			continue
+		}
+		contentPath := fmt.Sprintf("input.%d.content", i)
+		if content := gjson.GetBytes(updated, contentPath); content.Exists() && content.Type == gjson.Null {
+			updatedBody, errDel := sjson.DeleteBytes(updated, contentPath)
+			if errDel != nil {
+				return body
+			}
+			updated = updatedBody
+		}
+		encryptedContentPath := fmt.Sprintf("input.%d.encrypted_content", i)
+		if encryptedContent := gjson.GetBytes(updated, encryptedContentPath); encryptedContent.Exists() && encryptedContent.Type == gjson.Null {
+			updatedBody, errDel := sjson.DeleteBytes(updated, encryptedContentPath)
+			if errDel != nil {
+				return body
+			}
+			updated = updatedBody
+		}
+	}
+	return updated
+}
+
 func removeXAIEncryptedReasoningInclude(body []byte) []byte {
 	include := gjson.GetBytes(body, "include")
 	if !include.Exists() || !include.IsArray() {

internal/runtime/executor/xai_executor_test.go

@@ -55,7 +55,7 @@ func TestXAIExecutorExecuteShapesResponsesRequest(t *testing.T) {
 
 	_, err := exec.Execute(context.Background(), auth, cliproxyexecutor.Request{
 		Model:   "grok-4.3",
-		Payload: []byte(`{"model":"grok-4.3","input":"hello","include":["reasoning.encrypted_content"],"reasoning":{"effort":"high"},"tools":[{"type":"tool_search"},{"type":"image_generation"},{"type":"custom","name":"apply_patch"},{"type":"custom","name":"custom_lookup"},{"type":"function","name":"lookup"},{"type":"web_search","external_web_access":true,"search_content_types":["text","image"]}]}`),
+		Payload: []byte(`{"model":"grok-4.3","input":[{"type":"reasoning","summary":[{"type":"summary_text","text":"test"}],"content":null,"encrypted_content":null},{"role":"user","content":"hello"}],"include":["reasoning.encrypted_content"],"reasoning":{"effort":"high"},"tools":[{"type":"tool_search"},{"type":"image_generation"},{"type":"custom","name":"apply_patch"},{"type":"custom","name":"custom_lookup"},{"type":"function","name":"lookup"},{"type":"web_search","external_web_access":true,"search_content_types":["text","image"]}]}`),
 	}, cliproxyexecutor.Options{
 		SourceFormat: sdktranslator.FormatOpenAIResponse,
 		Stream:       false,
@@ -91,6 +91,15 @@ func TestXAIExecutorExecuteShapesResponsesRequest(t *testing.T) {
 	if gjson.GetBytes(gotBody, "reasoning.effort").String() != "high" {
 		t.Fatalf("reasoning.effort = %q, want high; body=%s", gjson.GetBytes(gotBody, "reasoning.effort").String(), string(gotBody))
 	}
+	if gjson.GetBytes(gotBody, "input.0.content").Exists() {
+		t.Fatalf("input.0.content exists, want removed; body=%s", string(gotBody))
+	}
+	if gjson.GetBytes(gotBody, "input.0.encrypted_content").Exists() {
+		t.Fatalf("input.0.encrypted_content exists, want removed; body=%s", string(gotBody))
+	}
+	if got := gjson.GetBytes(gotBody, "input.0.summary.0.text").String(); got != "test" {
+		t.Fatalf("input.0.summary.0.text = %q, want test; body=%s", got, string(gotBody))
+	}
 	tools := gjson.GetBytes(gotBody, "tools").Array()
 	if len(tools) != 3 {
 		t.Fatalf("tools length = %d, want 3; body=%s", len(tools), string(gotBody))
@@ -183,7 +192,7 @@ func TestXAIExecutorExecuteStreamFiltersToolSearchTool(t *testing.T) {
 
 	result, err := exec.ExecuteStream(context.Background(), auth, cliproxyexecutor.Request{
 		Model:   "grok-4.3",
-		Payload: []byte(`{"model":"grok-4.3","input":"hello","tools":[{"type":"tool_search"},{"type":"image_generation"},{"type":"custom","name":"apply_patch"},{"type":"custom","name":"custom_lookup"},{"type":"function","name":"lookup"},{"type":"web_search","external_web_access":true,"search_content_types":["text","image"]}]}`),
+		Payload: []byte(`{"model":"grok-4.3","input":[{"type":"reasoning","summary":[{"type":"summary_text","text":"test"}],"content":null,"encrypted_content":null},{"role":"user","content":"hello"}],"tools":[{"type":"tool_search"},{"type":"image_generation"},{"type":"custom","name":"apply_patch"},{"type":"custom","name":"custom_lookup"},{"type":"function","name":"lookup"},{"type":"web_search","external_web_access":true,"search_content_types":["text","image"]}]}`),
 	}, cliproxyexecutor.Options{
 		SourceFormat: sdktranslator.FormatOpenAIResponse,
 		Stream:       true,
@@ -201,6 +210,15 @@ func TestXAIExecutorExecuteStreamFiltersToolSearchTool(t *testing.T) {
 	if len(tools) != 3 {
 		t.Fatalf("tools length = %d, want 3; body=%s", len(tools), string(gotBody))
 	}
+	if gjson.GetBytes(gotBody, "input.0.content").Exists() {
+		t.Fatalf("input.0.content exists, want removed; body=%s", string(gotBody))
+	}
+	if gjson.GetBytes(gotBody, "input.0.encrypted_content").Exists() {
+		t.Fatalf("input.0.encrypted_content exists, want removed; body=%s", string(gotBody))
+	}
+	if got := gjson.GetBytes(gotBody, "input.0.summary.0.text").String(); got != "test" {
+		t.Fatalf("input.0.summary.0.text = %q, want test; body=%s", got, string(gotBody))
+	}
 	for i, tool := range tools {
 		toolType := tool.Get("type").String()
 		if toolType == "image_generation" {