A while back I had claude implement something, I don't quite remember what it was, but it chose Python. It was going to take hours. I told it to rewrite it in Rust and it was > 300000x faster. This is without any optimization or prompting particularly about performance, a short one shot lift.

echo "Python sucks, use something else when you can" >> ~/CLAUDE.md

Python was cool in 2005 in academia IT, all the rage in startup 2012. These days...