diff --git a/promptulate/client/chat.py b/promptulate/client/chat.py
index 84e6137e..59f1be68 100644
--- a/promptulate/client/chat.py
+++ b/promptulate/client/chat.py
@@ -34,7 +34,6 @@
     DuckDuckGoTool,
     HumanFeedBackTool,
     PythonREPLTool,
-    SleepTool,
 )
 from promptulate.tools.shell import ShellTool
 from promptulate.utils.color_print import print_text
@@ -46,7 +45,6 @@
     "WebSearch": DuckDuckGoTool,
     "Python Script Executor": PythonREPLTool,
     "Arxiv Query": ArxivQueryTool,
-    "Sleep": SleepTool,
     "Shell Executor": ShellTool,
     "HumanFeedBackTool": HumanFeedBackTool,
 }
@@ -173,6 +171,8 @@ def chat():
         llm = ChatOpenAI(model=model, temperature=0.0)
     elif "ernie" in model:
         llm = ErnieBot(model=model, temperature=0.1)
+    else:
+        raise ValueError(f"model {model} is not supported.")
 
     if terminal_mode == "Simple Chat":
         simple_chat(llm)
diff --git a/promptulate/tools/duckduckgo/tools.py b/promptulate/tools/duckduckgo/tools.py
index 7c75061f..62a5fdd2 100644
--- a/promptulate/tools/duckduckgo/tools.py
+++ b/promptulate/tools/duckduckgo/tools.py
@@ -1,5 +1,5 @@
 import time
-from typing import Dict, List, Union
+from typing import Dict, List, Optional, Union
 
 from promptulate.tools.base import Tool
 from promptulate.tools.duckduckgo.api_wrapper import DuckDuckGoSearchAPIWrapper
@@ -16,8 +16,12 @@ class DuckDuckGoTool(Tool):
         "Args : keyword(str)"
         "Input should be a search query."
     )
-    api_wrapper: DuckDuckGoSearchAPIWrapper = DuckDuckGoSearchAPIWrapper()
-    max_retry: int = 5
+
+    def __init__(self, max_retry: Optional[int] = None, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self.max_retry: int = max_retry or 5
+        self.api_wrapper = DuckDuckGoSearchAPIWrapper()
 
     def _run(self, keyword: str, **kwargs) -> Union[str, List[str]]:
         """Run duckduckgo search and get search result.
diff --git a/pyproject.toml b/pyproject.toml
index c6c1d74f..f76f9892 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ description = "A powerful LLM Application development framework."
 name = "promptulate"
 readme = "README.md"
 repository = "https://github.com/Undertone0809/promptulate"
-version = "1.15.1"
+version = "1.15.2"
 keywords = [
     "promptulate",
     "pne",