Hi, Rickard,
You are right using 'PTAgent.exe /install_silent' command for silent Parallels Tools installation. See detailed description in KB article http://kb.parallels.com/116161 It is still actual.
Note, that PTAgent is not a console application. If you want use scripting like this http://stackoverflow.com/questions/25999729/parallels-tools-silent-install-for-windows-platform you can modify your batch file. You can type in .cmd file
PTAgent.exe /install_silent
@echo %ERRORLEVEL%
or
start /wait PTAgent.exe /install_silent
@echo %ERRORLEVEL%
For other scripting systems use calls waiting for process completion. No special tricks required.
Note, that no reboot initiated with '/install_silent' key, but you must reboot guest Windows before using Parallels Tools. You can check return code, 0 means success as usual. Do not forget that installer requires administrative privileges.
Last edited: Mar 31, 2015