[DOC-11570] Explain session-stage references and lifetime

src/snowflake/snowpark/session.py

@@ -3269,6 +3269,24 @@ def get_session_stage(
         These artifacts include libraries and packages for UDFs that you define
         in this session via :func:`add_import`.
 
+        The return value is a Snowflake stage reference beginning with ``@``,
+        not a local directory or the contents of a file. Pass it to file
+        operations such as :meth:`FileOperation.put` to upload artifacts to
+        Snowflake. Treat this session-scoped temporary storage as disposable,
+        not as a permanent location for application data.
+
+        Example::
+
+            >>> stage = session.get_session_stage()  # doctest: +SKIP
+            >>> stage.startswith("@")  # doctest: +SKIP
+            True
+            >>> session.get_session_stage() == stage  # doctest: +SKIP
+            True
+
+        The stage name is generated by Snowpark, so don't hardcode the name
+        returned by another session. The first call can create a temporary
+        stage in Snowflake and requires a connection with appropriate privileges.
+
         Note:
             This temporary stage is created once under the current database and schema of a Snowpark session.
             Therefore, if you switch database or schema during the session, the stage will not be re-created