TeamCity Build Agent for jetbrains.com/teamcity. It is a piece of software which listens for the commands from the TeamCity server and starts the actual build processes. Install requires at least serverUrl parameter, e.g. -params 'serverurl=http://...', also supported are agentName, agentDir, ownPort and possibly others. If looking to see what changes in the agent config files during the run use -v argument to choco.exe.