diff --git a/README.md b/README.md
index afc2d28fe3..9fcfd92609 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,8 @@ Filing issues is helpful but **pull requests** that improve the docs are even be
 
 Learn how to [contribute to Angular.io](https://github.com/angular/angular.js/blob/master/CONTRIBUTING.md).
 
+> **IMPORTANT**: do _NOT_ make changes to cached files under `public/docs/ts/_cache`. Cached files are updated through a separate workflow.
+
 ## Development Setup
 This site relies heavily on node and npm.