Update LG_agent.py

LG_agent.py

@@ -41,8 +41,22 @@ class AgentState(TypedDict):
 # 3. Assistant node
 
 def assistant(state: AgentState):
+    # Inject tools description to a system message
+    tool_descriptions = "\n".join([
+        f"{tool.name}{inspect.signature(tool.func)}:\n    {tool.description.strip()}"
+        for tool in all_tools
+    ])
+
+    sys_msg = SystemMessage(
+        content=(
+            "You are a helpful AI assistant. You solve problems step by step and can use the following tools:\n"
+            f"{tool_descriptions}\n"
+            "Always plan your response, invoke tools explicitly if needed, and conclude with a direct answer."
+        )
+    )
+
     return {
-        "messages": [chat_with_tools.invoke(state["messages"])],
+        "messages": [chat_with_tools.invoke([sys_msg] + state["messages"])],
     }
 
 # 4. Build the agent graph