diff --git a/readme.md b/readme.md
index 33f8844149..7c40aee999 100644
--- a/readme.md
+++ b/readme.md
@@ -79,8 +79,12 @@ Then:
 
 ## Run the precommit hook before pushing a commit:
 
+First, install the latest version of [JSDoc3](https://github.com/jsdoc3/jsdoc). Then:
+
     $ ./build.py precommit
 
+This makes sure that your commit won't break the build. It also runs JSDoc3 to make sure that there are no invalid API doc directives. 
+
 ## Add examples
 
 The examples are located in the `examples` directory. Adding a new example