diff --git a/notebooks/4_full_agent.ipynb b/notebooks/4_full_agent.ipynb
index 6ba6cfe..10dbfb5 100644
--- a/notebooks/4_full_agent.ipynb
+++ b/notebooks/4_full_agent.ipynb
@@ -4345,6 +4345,7 @@
     }
    ],
    "source": [
+   "from utils import format_messages\n",
     "result = agent.invoke(\n",
     "    {\n",
     "        \"messages\": [\n",