diff --git a/metagpt/context.py b/metagpt/context.py
index ba859ed5c..71570bac6 100644
--- a/metagpt/context.py
+++ b/metagpt/context.py
@@ -9,7 +9,7 @@ import os
 from pathlib import Path
 from typing import Optional
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field
 
 from metagpt.config2 import Config
 from metagpt.configs.llm_config import LLMConfig, LLMType
@@ -42,31 +42,33 @@ class AttrDict(BaseModel):
             raise AttributeError(f"No such attribute: {key}")
 
 
-class LLMMixin:
+class LLMMixin(BaseModel):
     """Mixin class for LLM"""
 
+    model_config = ConfigDict(arbitrary_types_allowed=True)
+
     # _config: Optional[Config] = None
-    _llm_config: Optional[LLMConfig] = None
-    _llm_instance: Optional[BaseLLM] = None
+    llm_config: Optional[LLMConfig] = Field(default=None, exclude=True)
+    llm_instance: Optional[BaseLLM] = Field(default=None, exclude=True)
 
     def use_llm(self, name: Optional[str] = None, provider: LLMType = LLMType.OPENAI):
         """Use a LLM provider"""
         # 更新LLM配置
-        self._llm_config = self._config.get_llm_config(name, provider)
+        self.llm_config = self.config.get_llm_config(name, provider)
         # 重置LLM实例
-        self._llm_instance = None
+        self.llm_instance = None
 
     @property
     def llm(self) -> BaseLLM:
         """Return the LLM instance"""
-        if not self._llm_config:
+        if not self.llm_config:
             self.use_llm()
-        if not self._llm_instance and self._llm_config:
-            self._llm_instance = create_llm_instance(self._llm_config)
-        return self._llm_instance
+        if not self.llm_instance and self.llm_config:
+            self.llm_instance = create_llm_instance(self.llm_config)
+        return self.llm_instance
 
 
-class Context(LLMMixin, BaseModel):
+class Context(BaseModel):
     """Env context for MetaGPT"""
 
     model_config = ConfigDict(arbitrary_types_allowed=True)
@@ -93,14 +95,14 @@ class Context(LLMMixin, BaseModel):
         env.update({k: v for k, v in i.items() if isinstance(v, str)})
         return env
 
-    # def llm(self, name: Optional[str] = None, provider: LLMType = LLMType.OPENAI) -> BaseLLM:
-    #     """Return a LLM instance"""
-    #     llm_config = self.config.get_llm_config(name, provider)
-    #
-    #     llm = create_llm_instance(llm_config)
-    #     if llm.cost_manager is None:
-    #         llm.cost_manager = self.cost_manager
-    #     return llm
+    def llm(self, name: Optional[str] = None, provider: LLMType = LLMType.OPENAI) -> BaseLLM:
+        """Return a LLM instance"""
+        llm_config = self.config.get_llm_config(name, provider)
+
+        llm = create_llm_instance(llm_config)
+        if llm.cost_manager is None:
+            llm.cost_manager = self.cost_manager
+        return llm
 
 
 class ContextMixin:
diff --git a/metagpt/llm.py b/metagpt/llm.py
index f9a5aaedb..aff72d3c5 100644
--- a/metagpt/llm.py
+++ b/metagpt/llm.py
@@ -15,4 +15,5 @@ from metagpt.provider.base_llm import BaseLLM
 
 def LLM(name: Optional[str] = None, provider: LLMType = LLMType.OPENAI) -> BaseLLM:
     """get the default llm provider if name is None"""
+    # context.use_llm(name=name, provider=provider)
     return context.llm(name=name, provider=provider)