@Andrew Skullbriar is just Skullbriar though. Now it's every card, and on a per print basis even in hidden zones.

@Andrew Right, but what's that mean? In terms of the CR, it makes no sense at all. When two creatures fight during spell resolution, they both survive, and the spell won't see either one die. Later, during SBA, the creature dies.

This means the Arena client is doing some kind of look-ahead to check what will happen. How far does it look? What does it take into account?

For example, Oathsworn Knight doesn't take damage. Can it win/lose the fight? On what basis does it get its answer? What's it checking, so that we can consistently play correctly and know what outcome our actions should have?

Is it checking damage against toughness? Is it checking the next set of SBAs?

Let's say it checks SBAs. How far does it look? Here's a scenario: I have three creature cards in my graveyard. I control a 3/3 creature, and a 7/7 creature enchanted with Death's Approach getting -3/-3. You Threaten another one of my creatures which is a 3/3. Then they fight. Who survives?

The next time SBAs are checked, the 3/3 dies, because it has 4 damage marked on it. It goes to my graveyard. Then SBAs are checked again. The 7/7 dies, because it's now got -4/-4, and is reduced to being 3/3 with 3 damage marked on it. So does the "win the fight" mechanic decide the 7/7 wins, or nobody wins because they both died?

That may sound convoluted, but it's easily the kind of scenario where the answer could determine a championship win or loss for a player.

Now, I know the answers to these questions, but I only know those answers because someone had to dive into the client and repeatedly experiment against Sparky to suss out the exact answers (at least, as they currently stand). I know Oathsworn Knight dies when its last counter is removed, and I know the 7/7 wins the fight. The check seems to ask: "during the very next SBA check, would one creature die and the other survive?" It doesn't look beyond one step of SBAs, either.

But I don't know if that's the whole story, and I don't know there aren't any unusual edge cases.

I shouldn't have to basically datamine what a card does to determine how a mechanic works—I should be able to look at the CR and see how it should work for myself.

When Arena fails to meet the above expectation by providing me with a new edge case, I should know whether I'm looking at a bug ("this should have worked, and the client should be fixed") or whether the client has just told me there's a new facet of the rule I haven't yet discovered. With every other mechanic, when something unexpected happens we can tell if Arena's buggy by checking the CR—but for this mechanic, whatever the Arena behaviour is, is the source of truth.

The issue here is there's a class of cards where I am not sure what outcome I should expect when I use them in any but the most straightforward circumstance. What if I have just this card that could decide the win for me, and a non-straightforward circumstance I haven't tested before? I shouldn't be relying on faith that maybe it'll work the way I think it might and have no way at all of verifying except by doing it.

@Andrew Thanks! Ok, new layout is definitely friendly to that, and the deprecated mobile layout definitely isn't.

(er, rephrase: it only provides symbols for those that have it installed)

@doppelgreener Which is why they are online only - because the system has a very easy time keeping track of these where human players wouldn't - I do agree it was a bad direction to go in for magic, but I did like these kind of other effects in digital CCGS (I used to play and love Hex before it shut down for example)

@doppelgreener A good point there - it looks like the CR focuses on the paper game, there aren't additions for the keywords like Seek. This is an effect that could easily exist in paper though, and my guess would be it looks at the damage it took the same way the SBA itself looks (as modified by regeneration and indestructible) but we won't know for sure unless we datamine the card online or they make a "wins the fight" card in paper and 701.12 is updated to reflect that.

@doppelgreener The problem with scripts is of course that it relies on users installing them and changes the user experience from one person to the next. It also relies on users making post adhering to the formatting required to trigger the script. That all being said, curly braces are pretty much the standard for symbols but many just use letters and numbers unformatted, and most of those who use stack exchange sites have enough of a technical understanding to use scripts if they want them.

I'm somewhat torn there, but I'll stick to posting inline images as inline images in my answers, so everyone can see them unless and until SE adds site specific formatting like the [mtg:] card links for common magic symbols like mana, energy and tap.

@Andrew yep that's exactly the issue, and i do 100% agree with you sticking to inline images. i'm not trying to advocate using the script; the fact the script only creates a fancy experience for the handful of people who have it installed is a problem i want to fix.

@Andrew I was genuinely shocked that the new Arena mechanics weren't coming with a CR update. Arena's a bit divorced from paper magic, but ... it shouldn't be that divorced from it.

@Andrew Yeah I understand this is why it's online only, but I believe perpetual effects should exist even in online only, because even if the client's taking care of it, we still have to think about it as players playing the game.