Anthropics flagship frontier model — the deepest reasoning and longest-context model in the Claude family.
Claude Opus is the top of Anthropics model lineup — the one you reach for when the task is hard: a 300-page contract to summarize, a research paper to critique, or a novel to co-write. In 2026 Opus leads independent benchmarks on nuanced instruction-following and long-context reasoning, and its 200K-token window (1M on request) means you can drop an entire book in and ask questions about it. It is the "think hard" button of the AI world.
Who it's for: Researchers, analysts, lawyers, and writers who need the smartest available model for complex, long-form work.
Top scores on math, coding, and multi-step reasoning benchmarks.
Ingest entire books, codebases, or case files in one prompt.
Praised for natural, nuanced prose with minimal editing.
Refuses harmful requests transparently without being uselessly restrictive.
If quality matters more than speed or price, Claude Opus is the model to beat in 2026. It is slower and pricier than Haiku or Sonnet, but for genuinely difficult reasoning it earns the premium. Most people should run Sonnet day-to-day and save Opus for the tasks that warrant it.