diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 68d88854849..03b799574b2 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -36,11 +36,13 @@ Your pull request should:
  
 The library sources are in: [src/lib](https://github.com/Microsoft/TypeScript/tree/master/src/lib)
 
-To build the library files, run
+Library files in ```built/local/``` are updated by running
 ```Shell
-jake lib
+jake
 ```
 
+The files in ```lib/``` are used to bootstrap compilation and usually do not need to be updated.
+
 #### `src/lib/dom.generated.d.ts` and `src/lib/webworker.generated.d.ts`
 
 These two files represent the DOM typings and are auto-generated. To make any modifications to them, please submit a PR to  https://github.com/Microsoft/TSJS-lib-generator
diff --git a/lib/README.md b/lib/README.md
index b2837989505..71967e6a18a 100644
--- a/lib/README.md
+++ b/lib/README.md
@@ -1,4 +1,4 @@
 # Read this!
 
 These files are not meant to be edited by hand.
-If you need to make modifications, the respective files should be changed within the repository's top-level `src` directory.
\ No newline at end of file
+If you need to make modifications, the respective files should be changed within the repository's top-level `src` directory and ```jake LKG``` flushes the changes here.
\ No newline at end of file