For most of the past year, my view on AI coding tools was somewhat old-fashioned: great for prototyping, but not something I would trust with production code without a fair amount of rewriting.
Something has changed over the past two months.
The first thing is a formalization of how to actually do development with AI tools that I've been playing with: spec-driven development. Rather than just prompting and iterating, you invest upfront in a living specification to capture intent, and use that to drive the implementation. It changes the dynamic considerably. Instead of the AI guessing what you want, it has something to reason against.
More fundamentally though, it is the models themselves.
Claude Opus 4.6 in particular feels like a different category, not just an incremental improvement. Seems I'm not the only one who thinks so. Professor Knuth just published a paper titled "Claude's Cycles" describing how Opus 4.6 solved an open graph theory problem he had been working on for several weeks, in about an hour. He ends the paper with "Hats off to Claude!"
Clearly, I'm not the only one noticing this!