Is it possible to add or delete devices from the credentials repository outside of the CW gui? I know with cwcli I can do that with the RME database, but what about credentials?
You can use dcrcli to do this:
Using Command Line Interface, you can add, delete, modify, bulk import , and export devices, and change the Device and Credential Repository (DCR) modes. You can also view the list of attributes that can be stored in DCR, and view the current DCR mode. The dcrcli utility provided with Common Services helps you perform these tasks via CLI.
# Enter NMSROOT/bin/dcrcli -u Username.
where NMSROOT is the CiscoWorks installation directory.
# Enter the password corresponding to the username
Have a look at the online help for all options for this command utility