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MTG Bench: Testing how well LLMs can play Magic

46 pointsby CallumFergyesterday at 4:01 PM25 commentsview on HN

Comments

deractoday at 2:32 AM

I think running them against each other with a rules engine would be more interesting. Count up illegal moves and wins/unfinished games. I think llm grading is too unreliable.

lavaman131today at 5:16 AM

This is a really interesting benchmark and also timely given a lot of existing benchmarks don't do a good job. The mechanics and edge cases seem notoriously difficult to parse also even for perhaps human players. Have you been also plugging these into newer reasoning models to see how providing them with thinking time improves their win rate against the baseline?

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dash2today at 5:14 AM

You don't explain how scoring works, maybe it's obvious to MTG players? If you're using gpt 5.5, is there a possibility that it is biased in favour of models that think the way it does?

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josh_ptoday at 12:33 AM

I know the author specifically did not use a rules engine in their simulation because of uncertainty on how it would affect it.

I do still wonder if adapting something like card forge for llm use would result in engaging gameplay with an llm.

https://github.com/Card-Forge/forge

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alasdair_today at 4:07 AM

I wrote a rules engine in rust along with a reinforcement learning with MCTS based system to play decks against each other. It can handle aggro decks well enough but complex combo decks like Amulet Titan are tough to get working without expert demos or reward hacking.

OsrsNeedsf2Ptoday at 12:26 AM

I love obscure benchmarks, and I feel like I can trust their results a lot more - afterall, they (probably) weren't benchmaxxed. RuneBench[0] is another good example (how well LLMs can play Runescape)

[0] https://maxbittker.github.io/runebench/

thurntoday at 2:17 AM

To clarify, the more accurate description would be "Testing how well LLMs can follow the rules of Magic", right? There is no actual evaluation of how "well" they are playing?

purple-leafytoday at 1:59 AM

Benchmarks like this are onto something. Next frontier of llm benchmarking

jmccaftoday at 12:38 AM

Awesome ! Does this use https://mage-bench.com/ , or is it a separate project? I ran 4 local models in a tournament recently with mage-bench on an RTX 5090 ; Qwen 3.6 27B won narrowly over Gemma 4 .

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OwenCRtoday at 12:45 AM

Sadly this benchmark removes the part of MTG that is most interesting: the opponent(s). Without opponents you simply don't have a game. You just have a rules engine - quite boring!

I think I object more to the decks used in testing than the machines' decisions. I do have nit picks though: This hand is quite poor and should be mulliganned: https://app.mtgautodeck.com/public/benchmarks/4bd9955b-ebe1-.... The poor runout reinforces this decision.

This project is cool though, props for making it!

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danbrookstoday at 12:21 AM

Very cool. I’ve been daydreaming about whether LLMs can be used to reason through gaming decisions.

pilord314today at 1:35 AM

They should randomize games of judge tower and see who wins:

https://mtg.fandom.com/wiki/Judge_Tower

TZubiritoday at 1:22 AM

Looking forward to this metric being Goodhart lawed.

Like how the strawberry example was overtrained for, or how the pelican on a bike started being used in official release posts.