diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8a216d49c6..3f5ba3d1c0 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -51,6 +51,11 @@ Note that we are not accepting any new addons or modes into the main
 distribution. If you've written such a module, please distribute it as
 a separate NPM package.
 
+Code written by "AI" language models (either partially or fully) is
+**not welcome**. Both because you cannot guarantee it's not parroting
+copyrighted content, and because it tends to be of low quality and a
+waste of time to review.
+
 - Make sure you have a [GitHub Account](https://github.com/signup/free)
 - Fork [CodeMirror](https://github.com/codemirror/CodeMirror/)
   ([how to fork a repo](https://help.github.com/articles/fork-a-repo))