Plain-text tag list?

I’m looking for a way to display a plain-text list of tags to use as classes on my post elements, I’ve been trying

$tags = get_tags();
$tag_list = "";
foreach($tags as $tag){
    $tag_list .= $tag->name . " ";
}
echo "<li class=\"$tag_list\">";

in the loop but it seems to output all the tags instead of just the current post’s tags, so if I have tags x, y, and z, and I’m viewing a post with tag x I still get <li class="x y z"> anybody have any ideas as to how to show a plain-text list of tags or what I’m doing wrong?

You can play with arguments to only fetch what you need and get rid of loop:

$classes = implode(' ', wp_get_post_tags( get_the_ID(), array('fields' => 'names') ) );