A quick introduction to Chief Tools bots, what they do and how you can detect them.
AppName/X1X2X3X4
or AppNameBot/X1X2X3X4
when possible.
For example, Cert Chief might use the following user agent when monitoring your domains:
X1X2X3X4
part will be replaced with a unique identifier for the version of the bot that is making the request, this is a dynamic value that will change over time so do not use it for detection purposes. The value might look like 040bd810
or it might look like 1.0.0
.