OLS</code> environment variables. They can also be
    named in a similar manner to <a class="copy-link" href="#srcs">sources</a>.
  </p>

  <p>
    Note that since tools aren't copied, they can be a source of nondeterminism
    if you make use of other outputs that happen to be located near them. In
    order to ensure correctness you should make sure that you only run the tool
    itself and don't access neighbouring outputs.
  </p>

  <p>
    The distinction between tools and other sources or dependencie