After reading reams of documentation, finally I contacted Solarwinds support and received the following and submitted an enhancement request.
I'll see about creating a custom action, but for the time involved with that I might just invest time in RANCID.
Thank you for contacting Solarwinds Technical Support.
At this time there is no way to configure CatTools to monitor the TFTP Root and report on what is in it. Here's how the Device.Backup.TFTP Activity works:
1. Logs into the system and sends commands to have device upload its config file the TFTP Server.
2. CatTools compares the Device's file within the TFTP Root with the Device's file in the Current Configs directory.
-If a difference is found, the file in the Current Configs directory is dated and moved to the Dated Configs directory.
-If no difference is found, the Device's file is moved from the TFTP Root to the Current Configs directory, replacing the current file.
3. A report is sent out, if configured to do so.
The Device.Backup.Running Config directory works similarly however it uses the \ClientTMP\ directory instead of the TFTP Root directory.
At no point is the TFTP root directory contents scanned.
The closest thing would be to use the Report.Compare.Two files activity. You could configure it to run every x number of minutes and have it compare a specific file in the TFTP Root directory with a specific file in the Current Configs directory. If it finds any differences, it can send you an email with a report. It will, however, not move any files. More on this Activity is found here:
Let me know if this helps.