diff --git a/requirements.txt b/requirements.txt
index 425086c..45c8b0c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,8 +4,10 @@
 
 # For LLM-backed iterative planning only (agent-side):
 # Keep these lean so sandbox tests pass reliably.
-deepagents>=0.5.0
-langchain>=0.3
-langchain-openai>=0.2
-langgraph>=0.6
+# DeepAgents + LangChain are optional until the iterative skill is invoked.
+# Use conservative version ranges known to work on Python 3.11.
+deepagents>=0.4,<1.0
+langchain>=0.2.14,<0.4
+langchain-openai>=0.1.15,<0.3
+langgraph>=0.1.0,<0.8
 beautifulsoup4>=4.12