How to manage your project's toolchain in 2016

Today, dependency management in PHP projects is done using Composer. While this makes perfect sense for libraries, managing the toolchain via Composer will lead to the installation of all the dependencies of these tools. Not only is this slow, but it will also mix them with your project's runtime libraries. And even though most tools are available as a fully self-contained and executable PHP archive (PHAR), installing and updating them manually is everything but fun. If only there was a way to automate this ...