diff --git a/agents-api/agents_api/routers/sessions/chat.py b/agents-api/agents_api/routers/sessions/chat.py
index 76ef4eadd..2f336027c 100644
--- a/agents-api/agents_api/routers/sessions/chat.py
+++ b/agents-api/agents_api/routers/sessions/chat.py
@@ -69,6 +69,8 @@ async def chat(
     for m in past_messages:
         with suppress(KeyError):
             del m["created_at"]
+        with suppress(KeyError):
+            del m["id"]
 
     messages = past_messages + new_messages