diff --git a/email_priority_classifier/classifier/classifier_gptoss.py b/email_priority_classifier/classifier/classifier_gptoss.py
index a975616..9a9b633 100644
--- a/email_priority_classifier/classifier/classifier_gptoss.py
+++ b/email_priority_classifier/classifier/classifier_gptoss.py
@@ -63,7 +63,7 @@ def calc(self, thread_messages: list[ClassifiedEmailData]) -> EmailPriority:
                 input=request_input
             )
 
-            logger.debug(f"GPTOSS request_data: {json.dumps(request_input, indent=2)}")
+            logger.debug(f"GPTOSS request_data: {json.dumps(request_input, indent=2, ensure_ascii=False)}")
         except Exception as e:
             raise EmailPriorityClassifierOpenAIException("Some error occurred while calling the GPTOSS API.") from e
 
diff --git a/email_priority_classifier/classifier/classifier_openai.py b/email_priority_classifier/classifier/classifier_openai.py
index 3f82ce2..eda4611 100644
--- a/email_priority_classifier/classifier/classifier_openai.py
+++ b/email_priority_classifier/classifier/classifier_openai.py
@@ -28,7 +28,7 @@ def calc(self, thread_messages: list[ClassifiedEmailData]) -> EmailPriority:
         try:
             data = {
                 "thread_subject": thread_messages[0].subject,
-                "thread_messages": super()._encode_thread_messages(thread_messages)[:1500],  # 大体4000前後input-tokenくらい
+                "thread_messages": super()._encode_thread_messages(thread_messages)[:2500],  # 大体4000前後input-tokenくらい
             }
             response = _CLIENT.responses.create(
                 # model="gpt-5-nano",
@@ -41,7 +41,7 @@ def calc(self, thread_messages: list[ClassifiedEmailData]) -> EmailPriority:
                 }
             )
 
-            logger.debug(f"OpenAPI request_data: {json.dumps(data, indent=2)}")
+            logger.debug(f"OpenAPI request_data: {json.dumps(data, indent=2, ensure_ascii=False)}")
         except Exception as e:
             raise EmailPriorityClassifierOpenAIException("Some error occurred while calling the OpenAI API.") from e
 
diff --git a/email_priority_classifier/classifier/email_priority_classifier.py b/email_priority_classifier/classifier/email_priority_classifier.py
index 6a7ffca..39ebf41 100644
--- a/email_priority_classifier/classifier/email_priority_classifier.py
+++ b/email_priority_classifier/classifier/email_priority_classifier.py
@@ -12,7 +12,7 @@ def _encode_thread_messages(thread_messages: list[ClassifiedEmailData]) -> str:
         return json.dumps({
             "labels": list(labels),
             "messages": thread_messages
-        }, cls=ClassifiedEmailDataEncoder)
+        }, cls=ClassifiedEmailDataEncoder, ensure_ascii=False)
 
     @abstractmethod
     def calc(self, thread_messages: list[ClassifiedEmailData]) -> EmailPriority:
diff --git a/email_priority_classifier/type/classified_email_data.py b/email_priority_classifier/type/classified_email_data.py
index 6f1f7aa..2a1086f 100644
--- a/email_priority_classifier/type/classified_email_data.py
+++ b/email_priority_classifier/type/classified_email_data.py
@@ -37,7 +37,8 @@ def _extract_subject_from_payload(payload: dict) -> str:
 
     @staticmethod
     def _decode_body(body: str, headers: list[dict]) -> str:
-        return base64.urlsafe_b64decode(body).decode("utf-8")
+        return (base64.urlsafe_b64decode(body).decode("utf-8")
+                .replace("\r", "").replace("\n", "").replace("\t", ""))
         """
         for header in headers:
             if header.get("name", "").lower() == 'content-transfer-encoding':
@@ -61,7 +62,7 @@ def get_data(self) -> str:
         body = payload.get("body", {})
         if len(body) != 0 and body.get("size", 0) != 0:
             data = self._decode_body(body["data"], payload.get("headers", []))
-            return json.dumps(data)
+            return data
 
         text_parts = [part for part in payload.get("parts", []) if part.get("mimeType", "").startswith("text/")]
         if len(text_parts) == 0:
@@ -75,9 +76,9 @@ def get_data(self) -> str:
                 if body_data is None:
                     return "body data could not found."
                 data = self._decode_body(text_part["body"]["data"], text_part.get("headers", []))
-                return json.dumps(data)
+                return data
 
-        return json.dumps(text_parts[0])
+        return json.dumps(text_parts[0], ensure_ascii=False)
 
     @classmethod
     def init(cls, message: dict, personal_labels_info: dict[str, str]) -> "ClassifiedEmailData":