Auto set draft model path for MTP (#5793)

python/sglang/srt/configs/model_config.py

@@ -47,6 +47,7 @@ class ModelConfig:
         dtype: str = "auto",
         quantization: Optional[str] = None,
         override_config_file: Optional[str] = None,
+        is_draft_model: bool = False,
     ) -> None:
 
         self.model_path = model_path
@@ -85,6 +86,12 @@ class ModelConfig:
             else:
                 enable_multimodal = True
 
+        if (
+            is_draft_model
+            and self.hf_config.architectures[0] == "DeepseekV3ForCausalLM"
+        ):
+            self.hf_config.architectures[0] = "DeepseekV3ForCausalLMNextN"
+
         # Check model type
         self.is_generation = is_generation_model(
             self.hf_config.architectures, is_embedding