Anecdata but I’ve found Claude code with Opus 4.5 able to do many of my real tickets in real mid and large codebases at a large public startup. I’m at senior level (15+ years). It can browse and figure out the existing patterns better than some engineers on my team. It used a few rare features in the codebase that even I had forgotten about and was about to duplicate. To me it feels like a real step change from the previous models I’ve used which I found at best useless. It’s following style guides and existing patterns well, not just greenfield. Kind of impressive, kind of scary