An initial cryptomatte implementation is available. The standard cryptomatte workflow does not change. There are a few notable differences, however.
Since we need to pipe the cryptomatte aov's through lentil, we need to replace the cryptomatte library as described in the Installation.
The only change made is to force cryptomatte to create AOV's with a
lentil_filter instead of a
Add the crypto_* aov's & create a cryptomatte AOV shader. You can follow the Arnold documentation for this setup.
On the camera shader, enable the Cryptomatte parameter.