[Everlag]

I'm obligated to mention xmage: http://xmage.de/

Think cockatrice that trades ergonomics for a rules engine. Much easier to play when the game just 'works'. It even has loop detection for when you go infinite with triggers.

One thing to note is the community run servers are plagued with performance hitches at peak time. If you play regularly on xmage with friends, I'd recommend making an image on your preferred VPS provider and spinning up an instance when y'all want to play.

[platz]

I do kind of like the manual aspect of cockatrice instead of the automated experience of arena. It feels more like an actual sit-down game IRL. But there are certainly cons, folks frequently miss triggers or debate rules. Still that's magic. I poked around xmage and found it rather difficult. Cockatrice definitely has a learning curve too, but my first impression did not bode well.

[schoen]

> It even has loop detection for when you go infinite with triggers.

Apparently since you can construct a Turing machine in Magic: The Gathering, this is a case where halting is formally undecidable in general. :-)

(not to suggest that any actual players have ever achieved a position in real play that would be undecidable by this engine)

[whatshisface]

Uncomputable problems in MTG were an issue for a while but can be handily solved with this card[0].

[0] https://scryfall.com/card/pvan/304/oracle?utm_source=mw_MTGW...