{
  "function": {
    "name": "welcome_message",
    "arguments": "{\"action\":\"iPhoneやiPadなど、Apple製品についてどのようなことにお困りですか？\",\"nudge\":\"Apple製品について、テクニカルサポートに今すぐ相談可能です。\"}"
  }
}

{
  "function": {
    "name": "welcome_message",
    "arguments": "{\"action\": \"iPhone\\u3084iPad\\u306a\\u3069\\u3001Apple\\u88fd\\u54c1\\u306b\\u3064\\u3044\\u3066\\u3069\\u306e\\u3088\\u3046\\u306a\\u3053\\u3068\\u3067\\u304a\\u56f0\\u308a\\u3067\\u3059\\u304b\\uff1f\", \"nudge\": \"Apple\\u88fd\\u54c1\\u306b\\u3064\\u3044\\u3066\\u3001\\u30c6\\u30af\\u30cb\\u30ab\\u30eb\\u30b5\\u30dd\\u30fc\\u30c8\\u306b\\u4eca\\u3059\\u3050\\u76f8\\u8ac7\\u53ef\\u80fd\\u3067\\u3059\\u3002\"}"
  }
}

import litellm

response = litellm.completion(
    model="google/gemini-2.5-flash",
    messages=[
        {
            "role": "system",
            "content": "You are a helpful assistant that creates Japanese messages."
        },
        {
            "role": "user",
            "content": "apple technology"
        }
    ],
    tools=[{
        "type": "function",
        "function": {
            "name": "welcome_message",
            "description": "Creates copy for Japanese site",
            "parameters": {
                "type": "object",
                "properties": {
                    "action": {
                        "type": "string",
                        "description": "Action text in Japanese"
                    },
                    "nudge": {
                        "type": "string",
                        "description": "Nudge text in Japanese"
                    }
                },
                "required": ["action", "nudge"]
            }
        }
    }],
    tool_choice={
        "type": "function",
        "function": {"name": "welcome_message"}
    }
)

function_call = response.choices[0].message.tool_calls[0].function
print(function_call.arguments)  # Will contain \u3084 instead of や2. Observe that the `arguments` field contains escaped Unicode sequences instead of the original Japanese characters.