While @TimRice is correct that you can monitor BigFix with content/policies, the downside to doing so is that your implementation can encounter stability, performance or other issues with the BESClient. While this doesn’t happen often, it did happen back in v9.5.5 with the lines of file inspector for all NIX endpoints. In that case the service PID remained up, but it became completely unresponsive to any/all commands. In that scenario any monitoring via content/policies would be rendered useless until the BESClient is restarted.
Issue 138234 - APAR IV93412 - SLOW EVALUATION CYCLE FOR CLIENTS 9.5.X WHEN USING “LINES OF FILE” INSPECTOR
While it’s more work and infrastructure to implement an external monitoring solution like Nagios, it does offer an higher degree of reliability for monitoring and alerting. In many medium to large enterprises there may be an existing monitoring solution that you can leverage for this purpose.