Why request doesn't work with slash in the end of URL

In Controller I have this method:

Code:

public function webhook()
    {
        $request = \Config\Services::request();

        $hook_request = $request->getJSON();
        var_dump($hook_request);
        }

if I send request like http://localhost/controller/webhook - this works
If I send http://localhost/controller/webhook/ it's not worked
What is wrong?