Hi,
I assume you're referring to Pawtucket with regards to tag searches? If so, you can restrict those searches by prepending the field code for tags (ca_item_tags.tag) to the sarch.
Browse facets can operate on tags. The browse facet config looks like this;
tags = { type = tags, group_mode = none, multiple = 1, exclude_values = [null], label_singular = _("Tag"), label_plural = _("Tags") },
Seth