diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fd9c7a8a4f..e9fb44c681 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -107,6 +107,8 @@ The configuration is in `.vale.ini` in the root of the project.
 
 We use [Markdownlint](https://github.com/DavidAnson/markdownlint) to check that the Markdown in our docs is well formatted. The checks run as part of the pull request, and you can also run this tool locally. Follow the instructions from the markdownlint project page, and then run `markdownlint docs/` in the top-level folder of this repository.
 
+> Note that prettier also runs and reformats Markdown files. Use `npm run prettier` from the root of the project.
+
 ### Markdown link checking
 
 We use [`mlc`](https://github.com/becheran/mlc) to check the links in the `docs/` folder. This tool runs automatically on every pull request, but you can also run it locally if you want to. Visit the project homepage to find the installation instructions for your platform, and then run the command like this: