x.com
Add to X List
Input
handle requiredThe account's @handle to add, without the @ (e.g. "MKBHD"). Must be an exact handle - the picker's search is a general people-search, so a partial or display-name query can surface lookalike or parody accounts above the real one.
listId requiredThe target List's id, from its URL: x.com/i/lists/<listId> (returned by create_list, or visible on any List page).
Output
handle requiredlist_id requiredalready_member requiredmember_count_after requiredmember_count_before required