#compdef -k complete-word \C-xh

_complete_help() {
  local _sort_tags=_help_sort_tags text i
  typeset -A help_tags
  typeset -U help_contexts

  help_contexts=()

  compadd() { return 1 }

  _main_complete

  unfunction compadd

  for i in "$help_contexts[@]"; do
    text="${text}
tags in context \`${i}': ${help_tags[$i]}"
  done

  compstate[list]=list
  compstate[force_list]=yes
  compstate[insert]=''

  compadd -UX "$text[2,-1]" -n ''
}

_help_sort_tags() {
  help_contexts=( "$help_contexts[@]" "$curcontext" )
  help_tags[$curcontext]="${help_tags[$curcontext]}
    ${argv}"
  comptry "$@"
}

_complete_help "$@"