Work

building/tooling/test-runners/libraries.md

@@ -6,25 +6,28 @@ Exercises must thus, with few exceptions, be solvable without using libraries.
 
 ## Reasons to support libraries
 
-There are couple of reasons why a track might still want to support using libraries:
+There are couple of reasons why a track might still want to support libraries:
 
-1. The language has a minimal standard library and it is idiomatic to use libraries to add functionality.
+1. The language has a (very) minimal standard library.
    An example of such a language is Rust.
-2. The exercise is only really solvable using libraries.
-   An example of such an exercise is the [lens-person exercise](https://exercism.org/exercises/lens-person), which in many languages can only be solved using a library.
-3. The library adds testing functionality.
+2. The library adds testing functionality.
    An example is a library that adds support for property-based testing.
+3. The exercise can only be solved using a library.
+   An example of such an exercise is the [lens-person exercise](https://exercism.org/exercises/lens-person), which in most languages can only be solved using a library.
 
 ## Supporting libraries in the test runner
 
 As the test runner does not have access to the internet whilst running, it is not possible to download libraries at run time.
 The **only** solution to this problem is to install/download libraries at build time, where you _do_ have access to the internet.
 In practice, this means you'll need to install/download libraries within the Dockerfile.
 
-https://github.com/exercism/prolog-test-runner/blob/ed7447a7518ede6ee3405e649f50aaec828e318b/Dockerfile
+As an example, the [Prolog test runner's Dockerfile](https://github.com/exercism/prolog-test-runner/blob/ed7447a7518ede6ee3405e649f50aaec828e318b/Dockerfile) installs the `date_time` library:
+
+```dockerfile
+RUN swipl pack install date_time -y
+```
 
 ## Documentation
 
-If your track supports additional
-(/docs/building/tracks/docs)
-We recommend creating a document in the track repo's `docs` directory that lists the libraries that people can use, po
+If your track supports libraries, this should be documented in a [track doc](/docs/building/tracks/docs).
+Please also link to this document (using its full URL) from the [`exercises/shared/.docs/help.md` document](/docs/building/tracks/shared-files#file-help-md).