It seems MUCH better at tool usage. Just had an example where I asked Sonnet 4 to split a PR I had after we had to revert an upstream commit.

I didn't want to lose the work I had done, and I knew it would be a pain to do it manually with git. The model did a fantastic job of iterating through the git commits and deciding what to put into each branch. It got everything right except for a single test that I was able to easily move to the correct branch myself.