cakephp-tools/docs/Features.md

Useful Features

Debugging

Use Configure::write('App.monitorHeader', true); to assert, that all controller actions don't (accidently) sent any headers prior to the actual response->send() call. It will throw an exception in debug mode, and trigger an error in productive mode.

Make sure your AppController extends the Tools plugin MyController.

By default it is not active, and when activated via bootstrap you can always temporarally or locally deactivate it for specific controllers/actions.