This error occurs when the Chirp class is not properly autoloaded in the tinker environment. To fix this, try running the following command in your terminal:
composer dump-autoload
This will regenerate the autoload files and should allow tinker to find the Chirp class. If that doesn't work, make sure that the Chirp class is properly namespaced and located in the correct directory.
If you're still having issues, try manually including the Chirp class in tinker by running the following command:
require_once app_path('Chirp.php');
This should allow you to use the Chirp class in tinker.