app/Providers/AppServiceProvider.php:maxLength() and only in that closure call getInputMode().::configureUsing() is called immediately when someone does TextInput::make(). So at that point, if you call getInputMode() then the code in the configureUsing does not yet know what other methods are chained after it, so hence it doesn't work (what you also said).getInputMode() at run-time, when the getMaxLength() function is actually being called: