Anthropic

Claude Opus 4.8

Anthropic's flagship — the deepest reasoning of the lineup.

Claude Opus 4.8 is Anthropic's most capable model, built for hard problems that reward careful, multi-step thinking. On vexer it's the model to reach for when the answer matters more than the price of a single message.

Strengths

• Long, careful reasoning over complex or ambiguous problems
• Large-codebase understanding and multi-file code changes
• Following detailed instructions and staying on-task across a long chat
• Nuanced writing and analysis that holds a consistent thread

Best for

• Architecture decisions and code review
• Research summaries and long-document analysis
• Anything where a wrong answer is expensive

Use claude-opus-4-8 in the API, or pick Claude Opus 4.8 in the chat. Compare it in the model catalog.