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+# Command-line utility scripts
+
+Sometimes you may want to add a script to the repository that's meant to be
+used from the command line, not from a browser (e.g., a script for generating
+test files). If you want to ensure (e.g., for security reasons) that such
+scripts won't be handled by the HTTP server, but will instead only be usable
+from the command line, then place them in either:
+
+* the `tools` subdir at the root of the repository, or
+
+* the `tools` subdir at the root of any top-level directory in the repository
+  which contains the tests the script is meant to be used with
+
+Any files in those `tools` directories won't be handled by the HTTP server;
+instead the server will return a 404 if a user navigates to the URL for a file
+within them.
+
+If you want to add a script for use with a particular set of tests but there
+isn't yet any `tools` subdir at the root of a top-level directory in the
+repository containing those tests, you can create a `tools` subdir at the root
+of that top-level directory and place your scripts there.
+
+For example, if you wanted to add a script for use with tests in the
+`notifications` directory, create the `notifications/tools` subdir and put your
+script there.