diff --git a/pyproject.toml b/pyproject.toml
index 3c94322..f1dc6c7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,7 @@
 name = "lang_agent" 
 version = "0.1"   
 dependencies = [
-    "langchain>=1.0",
+    "langchain==1.0",
     "langchain_community",
     "langchain-openai",
     "httpx[socks]",