Opus is the top of Anthropic’s lineup — the model to reach for when a task rewards depth over speed: multi-step reasoning, agentic coding across a whole repository, and synthesizing long, messy context into something coherent.
It’s the default a brain runs on, because most of what people ask a brain to do is genuinely open-ended. When you need the strongest available judgment and are willing to pay for it, this is the one.
Best for: hard reasoning, agentic coding, long-document synthesis, anything where a wrong answer is expensive.