diff --git a/pyproject.toml b/pyproject.toml
index 39b6f9c9..88eb7126 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ requires-python = ">=3.11"
 dependencies = [
     "asyncio==4.0.0",
     "fastapi[standard]==0.136.3",
-    "langchain==1.2.15",
+    "langchain==1.3.9",
     "langchain-google-genai==4.2.6",
     "langchain-mcp-adapters==0.3.0",
     "langchain-ollama==1.1.0",