Add allowed labels to a select, select_number, or tag column. A select column’s options are explicit schema: SQL accepts exactly the labels the column carries and rejects everything else, so a value that does not exist yet has to be added here before it can be written. Use this when the user names a new status, stage, or category, or when a write they asked for was refused for an unknown option. Labels the column already has are ignored, so it is safe to send the whole set. A select_number column’s labels must be numbers. This is add-only — options are never renamed or removed here, because both would change what rows already holding them mean. Requires edit access. The response is the column after the change, with the labels SQL now accepts, plus the database’s refreshed schema. If database is null, the option change was still saved; heed warning and DescribeDatabase before continuing. Do not treat a failed follow-up read as a rejected mutation.