Out of curiosity - how did you figure this out? I cannot find any hints about that. Was it the language used?
or another example, the following sentence:
"handlers/ is flat — no subdirectories"
who writes like this? you'd just write "handlers/ is a flat folder" or similar.
The biggest tell for me is overuse of the term "silently". "quietly" is another one you often see from Claude in particular. Models love adverbs for whatever reason, whereas a human writer would use them in moderation for emphasis or prefer terms like "by accident".
It's how you see a painting and you know it's by Picasso, let's say, or you read an author and you know it's Hemingway. Everyone has their own unique style, and so does Claude. It's just that Claude is the most prolific writer in human history now.