Yes. Opus could do a lot better, but fails a lot because it doesn't respect the given formatting instructions/output format.
I could modify the tests to emphasize the requirements, but then, what's the point of a test. In real life, we expect the AI to do something if we ask it, especially for agentic use-case or in n8n, because if the output is slightly wrong, the entire workflow fails.
I got similar results for most models, with gemini 3 flash (with reasoning) being the most consistent/reliable model: https://aibenchy.com
I also noticed the same thing: some models reason correctly but draw the wrong conclusions.
And MiniMax m2.5 just reasons forever (filling the entire reasoning context) and gives wrong answers. This is why it's #1 on OpenRouter, it burns through tokens.
It's a bit hard to trick reasoning models, because they explore a lot of the angles of a problem, and they might accidentally have an "a-ha" moment that leads them on the right path. It's a bit like doing random sampling and stumbling upon the right result after doing gradient descent from those points.
I am trying to think what's the best way to give most information about how the AI models fail, without revealing information that can help them overfit on those specific tests.
I am planning to add some extra LLM calls, to summarize the failure reason, without revealing the test.
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