Get the history name and encoded id from inside a Galaxy tool.

history_context.xml

<tool id="history_context" name="history_context" version="1.0.0">
  <command>
    #set $history_id=$__app__.security.encode_id($output_dataset.creating_job.history.id)
    #set $history_name=$output_dataset.creating_job.history.name
    echo $history_id > $output_dataset;
    echo $history_name >> $output_dataset;
  </command>
  <inputs>
    <param name="ignored" type="integer" value="0" />
  </inputs>
  <outputs>
    <data format="txt" name="output_dataset" />
  </outputs>
</tool>