Claude Sonnet 4.5 and Claude Code 2 Initial Impressions

I’ve been playing with 4.5 and Claude Code 2 for a few days now. And I’ve used it via Claude Code and via API in Zendesk App Builder. In general it seems better and faster and tool calls definitely seems faster compared to the pervious version. Also I’ve noticed Claude Code taking more notes. And I’m yet to notice any context anxiety

Overalls it feels like an definite improvement. However, I struggle to quantify these improvements as a user. Like it’s better but it feels evolutionary not revolutionary. And it seems that Anthropic is listening to the community and watching whats happening among builders and then taking these lessons to the model training stages. For example, externalizing context/memory to the file system. This is great but I’m not feeling the AGI here, and it’s not a bad thing! :)

Claude Code 2 IDE integration on the hand, does feel revolutionary! It’s a huge improvement over the past version and I find myself spending more time in the IDE as a result.

Now, let’s wait for a few more days/weeks until the next big hit comes along. It’s going to be an exciting month! :)

Good reads on this

• https://www.anthropic.com/news/enabling-claude-code-to-work-more-autonomously
• https://simonwillison.net/2025/Sep/29/claude-sonnet-4-5/
• https://cognition.ai/blog/devin-sonnet-4-5-lessons-and-challenges