diff --git a/backend/debug.py b/backend/debug.py
new file mode 100644
index 0000000..5d5df3d
--- /dev/null
+++ b/backend/debug.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+"""
+Debug script for lead_agent.
+Run this file directly in VS Code with breakpoints.
+
+Usage:
+    1. Set breakpoints in agent.py or other files
+    2. Press F5 or use "Run and Debug" panel
+    3. Input messages in the terminal to interact with the agent
+"""
+
+import asyncio
+import os
+import sys
+
+# Ensure we can import from src
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+# Load environment variables
+from dotenv import load_dotenv
+from langchain_core.messages import HumanMessage
+
+from src.agents import make_lead_agent
+
+load_dotenv()
+
+
+async def main():
+    # Create agent with default config
+    config = {
+        "configurable": {
+            "thread_id": "debug-thread-001",
+            "thinking_enabled": True,
+            # Uncomment to use a specific model
+            "model_name": "doubao-seed-1.8",
+        }
+    }
+
+    agent = make_lead_agent(config)
+
+    print("=" * 50)
+    print("Lead Agent Debug Mode")
+    print("Type 'quit' or 'exit' to stop")
+    print("=" * 50)
+
+    while True:
+        try:
+            user_input = input("\nYou: ").strip()
+            if not user_input:
+                continue
+            if user_input.lower() in ("quit", "exit"):
+                print("Goodbye!")
+                break
+
+            # Invoke the agent
+            state = {"messages": [HumanMessage(content=user_input)]}
+            result = await agent.ainvoke(state, config=config, context={"thread_id": "debug-thread-001"})
+
+            # Print the response
+            if result.get("messages"):
+                last_message = result["messages"][-1]
+                print(f"\nAgent: {last_message.content}")
+
+        except KeyboardInterrupt:
+            print("\nInterrupted. Goodbye!")
+            break
+        except Exception as e:
+            print(f"\nError: {e}")
+            import traceback
+
+            traceback.print_exc()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
diff --git a/backend/langgraph.json b/backend/langgraph.json
index a3b5fe9..7c2c842 100644
--- a/backend/langgraph.json
+++ b/backend/langgraph.json
@@ -3,6 +3,6 @@
   "dependencies": ["."],
   "env": ".env",
   "graphs": {
-    "lead_agent": "src.agents:lead_agent"
+    "lead_agent": "src.agents:make_lead_agent"
   }
 }
diff --git a/backend/src/agents/__init__.py b/backend/src/agents/__init__.py
index cffde06..3bed203 100644
--- a/backend/src/agents/__init__.py
+++ b/backend/src/agents/__init__.py
@@ -1,4 +1,4 @@
-from .lead_agent import lead_agent
+from .lead_agent import make_lead_agent
 from .thread_state import SandboxState, ThreadState
 
-__all__ = ["lead_agent", "SandboxState", "ThreadState"]
+__all__ = ["make_lead_agent", "SandboxState", "ThreadState"]
diff --git a/backend/src/agents/lead_agent/__init__.py b/backend/src/agents/lead_agent/__init__.py
index 925259a..c93ffa7 100644
--- a/backend/src/agents/lead_agent/__init__.py
+++ b/backend/src/agents/lead_agent/__init__.py
@@ -1,3 +1,3 @@
-from .agent import lead_agent
+from .agent import make_lead_agent
 
-__all__ = ["lead_agent"]
+__all__ = ["make_lead_agent"]
diff --git a/backend/src/agents/lead_agent/agent.py b/backend/src/agents/lead_agent/agent.py
index 0773583..9f137d0 100644
--- a/backend/src/agents/lead_agent/agent.py
+++ b/backend/src/agents/lead_agent/agent.py
@@ -1,4 +1,5 @@
 from langchain.agents import create_agent
+from langchain_core.runnables import RunnableConfig
 
 from src.agents.lead_agent.prompt import apply_prompt_template
 from src.agents.middlewares.thread_data_middleware import ThreadDataMiddleware
@@ -11,10 +12,15 @@ from src.tools import get_available_tools
 # ThreadDataMiddleware must be before SandboxMiddleware to ensure thread_id is available
 middlewares = [ThreadDataMiddleware(), SandboxMiddleware(), TitleMiddleware()]
 
-lead_agent = create_agent(
-    model=create_chat_model(thinking_enabled=True),
-    tools=get_available_tools(),
-    middleware=middlewares,
-    system_prompt=apply_prompt_template(),
-    state_schema=ThreadState,
-)
+
+def make_lead_agent(config: RunnableConfig):
+    thinking_enabled = config.get("configurable", {}).get("thinking_enabled", True)
+    model_name = config.get("configurable", {}).get("model_name")
+    print(f"thinking_enabled: {thinking_enabled}, model_name: {model_name}")
+    return create_agent(
+        model=create_chat_model(name=model_name, thinking_enabled=thinking_enabled),
+        tools=get_available_tools(),
+        middleware=middlewares,
+        system_prompt=apply_prompt_template(),
+        state_schema=ThreadState,
+    )
diff --git a/backend/src/agents/lead_agent/prompt.py b/backend/src/agents/lead_agent/prompt.py
index c4ceb96..adfa588 100644
--- a/backend/src/agents/lead_agent/prompt.py
+++ b/backend/src/agents/lead_agent/prompt.py
@@ -1,4 +1,3 @@
-import os
 from datetime import datetime
 
 SYSTEM_PROMPT = f"""
diff --git a/backend/src/agents/middlewares/thread_data_middleware.py b/backend/src/agents/middlewares/thread_data_middleware.py
index 727e62f..2367f3f 100644
--- a/backend/src/agents/middlewares/thread_data_middleware.py
+++ b/backend/src/agents/middlewares/thread_data_middleware.py
@@ -71,8 +71,9 @@ class ThreadDataMiddleware(AgentMiddleware[ThreadDataMiddlewareState]):
     @override
     def before_agent(self, state: ThreadDataMiddlewareState, runtime: Runtime) -> dict | None:
         # Generate new thread ID and create directories
-        print(runtime.context)
-        thread_id = runtime.context["thread_id"]
+        thread_id = runtime.context.get("thread_id")
+        if thread_id is None:
+            raise ValueError("Thread ID is required in the context")
         paths = self._create_thread_directories(thread_id)
         print(f"Created thread data directories for thread {thread_id}")
 
diff --git a/backend/src/sandbox/tools.py b/backend/src/sandbox/tools.py
index a8ec9c5..3ab0c90 100644
--- a/backend/src/sandbox/tools.py
+++ b/backend/src/sandbox/tools.py
@@ -168,14 +168,16 @@ def read_file_tool(
     runtime: ToolRuntime[ContextT, ThreadState],
     description: str,
     path: str,
-    view_range: tuple[int, int] | None = None,
+    start_line: int | None = None,
+    end_line: int | None = None,
 ) -> str:
-    """Read the contents of a text file.
+    """Read the contents of a text file. Use this to examine source code, configuration files, logs, or any text-based file.
 
     Args:
-        description: Explain why you are viewing this file in short words. ALWAYS PROVIDE THIS PARAMETER FIRST.
+        description: Explain why you are reading this file in short words. ALWAYS PROVIDE THIS PARAMETER FIRST.
         path: The **absolute** path to the file to read.
-        view_range: The range of lines to view. The range is inclusive and starts at 1. For example, (1, 10) will view the first 10 lines of the file.
+        start_line: Optional starting line number (1-indexed, inclusive). Use with end_line to read a specific range.
+        end_line: Optional ending line number (1-indexed, inclusive). Use with start_line to read a specific range.
     """
     try:
         sandbox = sandbox_from_runtime(runtime)
@@ -185,9 +187,8 @@ def read_file_tool(
         content = sandbox.read_file(path)
         if not content:
             return "(empty)"
-        if view_range:
-            start, end = view_range
-            content = "\n".join(content.splitlines()[start - 1 : end])
+        if start_line is not None and end_line is not None:
+            content = "\n".join(content.splitlines()[start_line - 1 : end_line])
         return content
     except Exception as e:
         return f"Error: {e}"
diff --git a/deer-flow.code-workspace b/deer-flow.code-workspace
index 652a3f1..8622877 100644
--- a/deer-flow.code-workspace
+++ b/deer-flow.code-workspace
@@ -13,5 +13,34 @@
         "workspace": "deer-flow"
       }
     ]
+  },
+  "launch": {
+    "version": "0.2.0",
+    "configurations": [
+      {
+        "name": "Debug Lead Agent",
+        "type": "debugpy",
+        "request": "launch",
+        "program": "${workspaceFolder}/backend/debug.py",
+        "console": "integratedTerminal",
+        "cwd": "${workspaceFolder}/backend",
+        "env": {
+          "PYTHONPATH": "${workspaceFolder}/backend"
+        },
+        "justMyCode": false
+      },
+      {
+        "name": "Debug Lead Agent (justMyCode)",
+        "type": "debugpy",
+        "request": "launch",
+        "program": "${workspaceFolder}/backend/debug.py",
+        "console": "integratedTerminal",
+        "cwd": "${workspaceFolder}/backend",
+        "env": {
+          "PYTHONPATH": "${workspaceFolder}/backend"
+        },
+        "justMyCode": true
+      }
+    ]
   }
 }