The IS-IS administrative tags configured on an IS-IS router (or neighbor) will not have any effect until policies are configured to process the specified tag value.
Policies can process route tags that specify ISIS as either the origin or destination protocol, or as both origin and destination protocol.
config>router>policy-options>policy-statement>entry>from
config>router>policy-options>policy-statement>entry>action tag tag-value
config>router>policy-options>policy-statement# default-action tag tag-value