diff --git a/openviking/models/vlm/backends/litellm_vlm.py b/openviking/models/vlm/backends/litellm_vlm.py
index 7a951d732..3b946c244 100644
--- a/openviking/models/vlm/backends/litellm_vlm.py
+++ b/openviking/models/vlm/backends/litellm_vlm.py
@@ -199,6 +199,8 @@ def _build_kwargs(self, model: str, messages: list) -> dict[str, Any]:
             "messages": messages,
             "temperature": self.temperature,
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         if self.api_key:
             kwargs["api_key"] = self.api_key
diff --git a/openviking/models/vlm/backends/openai_vlm.py b/openviking/models/vlm/backends/openai_vlm.py
index de59b8dc7..643a57c4b 100644
--- a/openviking/models/vlm/backends/openai_vlm.py
+++ b/openviking/models/vlm/backends/openai_vlm.py
@@ -62,6 +62,8 @@ def get_completion(self, prompt: str, thinking: bool = False) -> str:
             "messages": [{"role": "user", "content": prompt}],
             "temperature": self.temperature,
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
@@ -77,6 +79,8 @@ async def get_completion_async(
             "messages": [{"role": "user", "content": prompt}],
             "temperature": self.temperature,
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         last_error = None
         for attempt in range(max_retries + 1):
@@ -165,6 +169,8 @@ def get_vision_completion(
             "messages": [{"role": "user", "content": content}],
             "temperature": self.temperature,
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
@@ -189,6 +195,8 @@ async def get_vision_completion_async(
             "messages": [{"role": "user", "content": content}],
             "temperature": self.temperature,
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = await client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
diff --git a/openviking/models/vlm/backends/volcengine_vlm.py b/openviking/models/vlm/backends/volcengine_vlm.py
index 985025cac..604d51bb7 100644
--- a/openviking/models/vlm/backends/volcengine_vlm.py
+++ b/openviking/models/vlm/backends/volcengine_vlm.py
@@ -68,6 +68,8 @@ def get_completion(self, prompt: str, thinking: bool = False) -> str:
             "temperature": self.temperature,
             "thinking": {"type": "disabled" if not thinking else "enabled"},
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
@@ -84,6 +86,8 @@ async def get_completion_async(
             "temperature": self.temperature,
             "thinking": {"type": "disabled" if not thinking else "enabled"},
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         last_error = None
         for attempt in range(max_retries + 1):
@@ -235,6 +239,8 @@ def get_vision_completion(
             "temperature": self.temperature,
             "thinking": {"type": "disabled" if not thinking else "enabled"},
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
@@ -260,6 +266,8 @@ async def get_vision_completion_async(
             "temperature": self.temperature,
             "thinking": {"type": "disabled" if not thinking else "enabled"},
         }
+        if self.max_tokens is not None:
+            kwargs["max_tokens"] = self.max_tokens
 
         response = await client.chat.completions.create(**kwargs)
         self._update_token_usage_from_response(response)
diff --git a/openviking/models/vlm/base.py b/openviking/models/vlm/base.py
index 66b859ba1..0bb6c4188 100644
--- a/openviking/models/vlm/base.py
+++ b/openviking/models/vlm/base.py
@@ -22,6 +22,7 @@ def __init__(self, config: Dict[str, Any]):
         self.api_base = config.get("api_base")
         self.temperature = config.get("temperature", 0.0)
         self.max_retries = config.get("max_retries", 2)
+        self.max_tokens = config.get("max_tokens")
 
         # Token usage tracking
         self._token_tracker = TokenUsageTracker()
diff --git a/openviking_cli/utils/config/vlm_config.py b/openviking_cli/utils/config/vlm_config.py
index eea7682bf..6c42d6436 100644
--- a/openviking_cli/utils/config/vlm_config.py
+++ b/openviking_cli/utils/config/vlm_config.py
@@ -26,6 +26,10 @@ class VLMConfig(BaseModel):
 
     default_provider: Optional[str] = Field(default=None, description="Default provider name")
 
+    max_tokens: Optional[int] = Field(
+        default=None, description="Maximum tokens for VLM completion output (None = provider default)"
+    )
+
     thinking: bool = Field(default=False, description="Enable thinking mode for VolcEngine models")
 
     max_concurrent: int = Field(
@@ -134,6 +138,7 @@ def _build_vlm_config_dict(self) -> Dict[str, Any]:
             "max_retries": self.max_retries,
             "provider": name,
             "thinking": self.thinking,
+            "max_tokens": self.max_tokens,
         }
 
         if config: