If you have some trouble with bower installation and detection on your own agent. A simple workaround is to add bower as a dependency in your project's package.json. The vsts-bower task will then find and use your local version of bower.
If you encounter some trouble with NetworkService account. Add the path from npm prefix -g to the global path and launch the task again.
(Optional). Select command to execute in bower. (Defaults to install).
(Optional). Set advanced settings.
Options
Command: Command to execute. Default:install.
Arguments: Additional arguments passed to bower. --config.interactive=false is not needed.
Bower JSON Path: Relative path to bower.json file. Default:bower.json. Also defines the Current Working Directory.
Bower CLI: Optional. bower runtime to run. When agent can't find this bower runtime nor global installed one, it will install bower locally before run (slower). Default:node_modules/bower/bin/bower.