diff --git a/navi/core/agent.py b/navi/core/agent.py
index 842880d..2ecca9e 100644
--- a/navi/core/agent.py
+++ b/navi/core/agent.py
@@ -338,7 +338,12 @@
         tool_schemas = [t.schema() for t in tools]
         llm = self._get_backend(profile.llm_backend)
 
-        mem = await self._ctx_builder._memory_msg(user_id=session.user_id)
+        user_id = None
+        if parent_session_id and self._sessions:
+            parent_session = await self._sessions.get(parent_session_id)
+            if parent_session:
+                user_id = parent_session.user_id
+        mem = await self._ctx_builder._memory_msg(user_id=user_id)
 
         # Build subagent system prompt — completely separate from the parent's system prompt.
         # No persona, no orchestrator instructions, no profiles block.