Code to display direct customer record link in the customer theme. Not needed if on default theme.

dc_link.txt

<div class="agent_customer_section">
  <span class="tab_label tab_label_case tab_label_case_direct_link label_desc">
    Direct Customer Link
  </span>
  <div class="tab_case_data">
    <input autocomplete="off" class="default long" id="customer_{{case.customer.id}}_direct_link" maxlength="100" name="direct_link[subject]" readonly="readonly" size="100" value="https://site_key.desk.com/agent/customer/{{customer.id}}" type="text">
  </div>
</div>