Cutzilla

Sonnet 5.5: First Impressions I had access to Sonnet 5.5 for a while during shadow testing, and I've also had time to work with the release version. I have a lot to say about it 1. It's incredibly diligent. Since it's a smaller, cheaper model, you can tell the harness was tuned hard for thoroughness. It never gets lazy. It works for a very long time and pushes all the way to the limit. Opus 5.5, by contrast, tends to micromanage, sometimes cuts corners, and always starts small 2. It loves to double- and triple-check its work, but it does so with taste, without GPT-style overengineering. There's a real sense of perfectionism to it. My guess is it was deliberately trained this way to make up for its smaller size and deliver frontier-level results 3. I'm very picky about code quality and constantly complain about the awful, bloated code GPT models produce. But Sonnet's code blew me away. It's simple, elegant, and minimal, a genuine pleasure to read. Where Fable might reach for clever ninja-code constructs, Sonnet writes code straight out of a programming textbook. It follows the language specs and standards to the letter 4. Because Sonnet was tuned not to be lazy, it now plans deeper and further ahead. It picks up on even indirect cues, and, my favorite part, it fills in missing context when what it has isn't enough. In my previous post I shared an example of 3D modeling a Roman legionary. As soon as it got the task, it started thinking about the historical context, recalling nuances and details from the era. It laid out its reasoning and described in text what it was going to model. GPT-6 Sol, on the other hand, acts first and thinks later, which drives me up the wall 5. Good taste no longer has to be expensive. Sonnet has an eye for aesthetics in everything: clean code, UI/UX design, 3D modeling, and its writing. Combined with its newfound diligence, that gives it a touch of perfectionism. It'll polish even the tiniest detail that's objectively off. It's now my go-to model in Claude Design 6. Its writing is at the same excellent level as Opus 5.5 and Astra. Its writing is clear and pleasant to read 7. I don't know what kind of RL magic Anthropic came up with, but Sonnet 5.5 doesn't feel like a small model at all in terms of intelligence. Ask it a hard technical question and you'll be surprised by its thought process. It'll look at the problem from multiple angles 8. On the subscription, the limits feel practically unlimited. On the Max 20x plan, after several days of work on xhigh, I seem to have used only about 5% of my weekly limit Conclustions I'd never used Sonnet, Terra, or any other mid- or small-tier models before. This looks like the first one that will make it into my daily workflow. It's so good that I barely noticed a difference from Opus 5.5, and in some ways it's even more pleasant to work with Compared to GPT-6 Sol, Sonnet 5.5 comes out ahead on every front. It's a real letdown that a model pitched as a Fable competitor now ranks below Sonnet