Documentation for MooseX::Clone is pretty clear about that, add 'NoClone' trait to attributes you don't want to clone:

use 5.010;
use strict;
use warnings;

{

    package Foo;
    use Moose;
    with 'MooseX::Clone';

    has bar => ( is => 'rw', default => 42, );
    has baz => ( is => 'rw', default => 42, traits => [qw(NoClone)], )
+;
}

my $foo = Foo->new( bar => 33, baz => 33 );
my $clone = $foo->clone;

say "Bar: ", $clone->bar;
say "Baz: ", $clone->baz;
__END__
Bar: 33
Baz: 42
[download]

Thanks, zwon.
Part of my brain must have been asleep when I read the manual.

But isn't that the point of cloning? If you want an object to have default attributes then just make a new one.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

The point is that some (few) attributes should never be cloned, while others should. In this case, I have some objects that are stored through KioukuDB, and it never makes sense that they get the same id as the original object.

I have a role that provides default ids, so it would be nice to have the clone method default to that.

Another thing I need to differentiate is between some attributes that should be shallow clones and others that should be deep clones (using the clone() method on them, of course).