你想写一个wp_insert_post_empty_content 滤器

WordPress已经try and reject empty posts:

$maybe_empty = \'attachment\' !== $post_type
    && ! $post_content && ! $post_title && ! $post_excerpt
    && post_type_supports( $post_type, \'editor\' )
    && post_type_supports( $post_type, \'title\' )
    && post_type_supports( $post_type, \'excerpt\' );

function wpse390344_empty_posts_filter( $empty, $postarr ) {
    if ( ! $empty ) {
        // TODO: look at $postarr - see wp_insert_post() documentation for format
        //       and decide if this is an empty post you want to reject.
        //       If it is, return true.
    }

    return $empty;
}
add_filter( \'wp_insert_post_empty_content\', \'wpse390344_empty_posts_filter\', 10, 2 );