Built-in variable is undefined

We have a template which uses the {{ansible_user_id}} pre-defined variable. On Ansible 1.5, running against localhost, we see this error:

TASK: [service | Stage deamontools run script] ********************************
fatal: [127.0.0.1] => {‘msg’: “One or more undefined variables: ‘ansible_user_id’ is undefined”, ‘failed’: True}
fatal: [127.0.0.1] => {‘msg’: “One or more undefined variables: ‘ansible_user_id’ is undefined”, ‘failed’: True}

FATAL: all hosts have already failed – aborting

Is this expected when going against localhost?

have you gathered facts? this is what sets the variable.