diff --git a/backend/services/ai_config.py b/backend/services/ai_config.py
index 93a1afb..6d3a912 100644
--- a/backend/services/ai_config.py
+++ b/backend/services/ai_config.py
@@ -8,5 +8,5 @@ load_dotenv()
 AI_API_BASE = os.getenv("AI_API_BASE", "https://openteam.oneisall.xyz/v1")
 AI_API_KEY = os.getenv("AI_API_KEY", "")
 AI_MODEL = os.getenv("AI_MODEL", "deepseek-v4-flash")
-AI_MAX_TOKENS = int(os.getenv("AI_MAX_TOKENS", "4096"))
-AI_TEMPERATURE = float(os.getenv("AI_TEMPERATURE", "0.7"))
+AI_MAX_TOKENS = int(os.getenv("AI_MAX_TOKENS")) if os.getenv("AI_MAX_TOKENS") else None
+AI_TEMPERATURE = float(os.getenv("AI_TEMPERATURE")) if os.getenv("AI_TEMPERATURE") else None
diff --git a/backend/services/ai_service.py b/backend/services/ai_service.py
index d93eeda..dcfc81a 100644
--- a/backend/services/ai_service.py
+++ b/backend/services/ai_service.py
@@ -80,9 +80,11 @@ async def call_llm(messages: list, tools: list = None) -> dict:
         payload = {
             "model": AI_MODEL,
             "messages": messages,
-            "max_tokens": AI_MAX_TOKENS,
-            "temperature": AI_TEMPERATURE,
         }
+        if AI_MAX_TOKENS is not None:
+            payload["max_tokens"] = AI_MAX_TOKENS
+        if AI_TEMPERATURE is not None:
+            payload["temperature"] = AI_TEMPERATURE
         if tools:
             payload["tools"] = tools
             payload["tool_choice"] = "auto"