SITUATION ANALYSIS: Claude Opus 5 After two months since Opus 4.8 and a month and a half since Fable 5, Claude Opus 5 has finally been released, and it seems to be a really good model, the best we’ve seen yet. For starters, it outperforms even Fable on most benchmarks Anthropic tested. On agentic software engineering, it performs similarly well to GPT-5.6 Sol on lower effort levels and even better at higher effort levels. It also does substantially better than any other model on ARC-AGI-3, a…