wp-less to style.css

functions.php

add_filter( 'wp_less_cache_path', 'my_less_cache_path' );
add_filter( 'wp_less_cache_url', 'my_less_cache_url' )

function my_less_cache_path( $path ) {
    return get_stylesheet_directory();
}

function my_less_cache_url( $url ) {
    return get_stylesheet_directory_uri();
}

Missing a semi-colon on the second add_filter