What about that makes you think it was written by AI?

Since you asked...I've gone to the effort to pull out the parts of the article that I think show it:

"That’s the part most benchmarks can’t see, and it’s what this post is about." Classic "it's not x, it's x", shows up in various forms throughout the article.

"To me, this is the most fascinating finding from this entire experiment - we saw very clear alignment tax being paid by certain models, which directly impacted their performance in this zero-sum game." - Usage of em dash. Now, yes, there's nothing wrong with using em dashes. But this feels like a weird place to use one. Also I counted at least 6 other emdashes in this article. Most people do not use em dashes that often.

"and a memory system that kept doubling down on what worked without second-guessing or doubting itself." - Doubling down is a classic Claudism.

"I want to be careful here..." - "wanting to be careful here" is another classic Claudism.

"The same game world, completely different results when in a different “task”." - "same X, completely different X" is another common one from Claude, as proofed by the repeated pattern later down: "These models were all given the same rules, same game world, and same tools, but each of them approached the game on a personality-level that is completely different from each other."

"It begs the question" - author used this twice in the article.

I'm guessing the author wrote a draft and then had Claude spruce it up a lot. I could be wrong and I'd be happy to be proven otherwise.

The style is very obvious.

Some snippets that display classic patterns:

“ Both of those things are true. That’s the part most benchmarks can’t see,”

“And it’s changing how I” (classic pattern found in a lot of LinkedIn AIslop)

“ I want to be careful here.”

“ The stats are the stats. The moments are the part I kept showing people. ”

All of the normal AI tells plus it's very long yet nearly incoherent.

Really I use the AI every damn day at work I don't get how people can't recognize instantly if something is completely AI, AI with light proofreading, or human written.

I would call this as AI with very light proofreading.