Installing 3rd party plugins is straight forward and handled through composer. In the root folder of your phpci instance update the composer.json file to include the new plugins you require:

"require": {
   \\...
   "meadsteve/example-phpci-plugin" : "dev-master",
   \\...
}

running composer update plugin-provider/plugin-package will then download the plugin.

Once a new plugin has been installed to phpci any project can make use of this plugin. The plugin is referenced in the phpci.yml as a full class name including namespaces:

setup:
  test:
  php_mess_detector:
    allowed_warnings: 0
  \meadsteve\PhpciPlugins\ExamplePlugin:
    option_one: 2

//TODO: document pluginconfig.php in project root.