diff --git a/optional-skills/data-science/jupyter-notebook/SKILL.md b/optional-skills/data-science/jupyter-notebook/SKILL.md
index 91ae015f5f4f..17d10c1232b3 100644
--- a/optional-skills/data-science/jupyter-notebook/SKILL.md
+++ b/optional-skills/data-science/jupyter-notebook/SKILL.md
@@ -160,6 +160,17 @@ uv run "$SCRIPT" restart-run-all --path <notebook.ipynb> --save-outputs --compac
 8. **Occasional websocket timeouts** — some operations may timeout on first try,
    especially after a kernel restart. Retry once before escalating.
 
+9. **If websocket consistently times out on this host**, force zmq transport:
+   `uv run "$SCRIPT" execute --transport zmq ...`. Symptom: every execute returns
+   "Websocket execution may already have reached the kernel, so auto fallback was
+   skipped". The kernel actually ran fine (REST shows execution_state=idle and
+   execution_count increments) — only the websocket reply channel is broken.
+   zmq transport uses jupyter_client directly and sidesteps the issue.
+
+10. **When starting a fresh server for REST-only use**, add
+    `--ServerApp.disable_check_xsrf=True` — otherwise POST /api/sessions returns
+    `"'_xsrf' argument missing from POST"` and kernel session creation fails.
+
 ## Timeout Defaults
 
 The script has a 30-second default timeout per execution. For long-running