diff --git a/lang_agent/graphs/react.py b/lang_agent/graphs/react.py
index c88730e..c040e63 100644
--- a/lang_agent/graphs/react.py
+++ b/lang_agent/graphs/react.py
@@ -1,6 +1,7 @@
-from dataclasses import dataclass, field, is_dataclass
-from typing import Type, List, Callable, Any, AsyncIterator
+from dataclasses import dataclass, field
+from typing import Type
 import tyro
+import os.path as osp
 
 from lang_agent.config import KeyConfig
 from lang_agent.components.tool_manager import ToolManager, ToolManagerConfig
@@ -24,12 +25,18 @@ class ReactGraphConfig(KeyConfig):
     llm_provider:str = "openai"
     """provider of the llm"""
 
+    sys_prompt_f:str = osp.join(osp.dirname(osp.dirname(osp.dirname(__file__))), "configs", "prompts", "blueberry.txt")
+    """path to system prompt"""
+
     base_url:str = "https://dashscope.aliyuncs.com/compatible-mode/v1"
     """base url; could be used to overwrite the baseurl in llm provider"""
 
     tool_manager_config: ToolManagerConfig = field(default_factory=ToolManagerConfig)
 
-
+    def __post_init__(self):
+        super().__post_init__()
+        err_msg = f"{self.sys_prompt_f} does not exist"
+        assert osp.exists(self.sys_prompt_f), err_msg
 
 
 class ReactGraph(GraphBase):
@@ -50,6 +57,21 @@ class ReactGraph(GraphBase):
         self.memory = MemorySaver()
         tools = self.tool_manager.get_langchain_tools()
         self.agent = create_agent(self.llm, tools, checkpointer=self.memory)
+        
+        with open(self.config.sys_prompt_f, "r") as f:
+            self.sys_prompt = f.read()
+
+    def _get_human_msg(self, *nargs):
+        msgs = nargs[0]["messages"]
+
+        candidate_hum_msg = None
+        for msg in msgs:
+            if isinstance(msg, HumanMessage):
+                candidate_hum_msg = msg
+                
+        assert isinstance(candidate_hum_msg, HumanMessage), "not a human message"
+
+        return candidate_hum_msg
     
     def invoke(self, *nargs, as_stream:bool=False, as_raw:bool=False, **kwargs):
         """