Welcome to Claude Opus

Claude Opus is the flagship model line in the Claude family. The latest version, Claude Opus 5.5, excels at agentic coding, knowledge work, long-document analysis, and clear writing, at about 40% lower cost than its predecessor.

Key Features

• Intelligence: Performs at the level of Anthropic's top-tier Fable 5.1 on most work, and leads GPT-6 Astra on agentic coding (66.4% vs 57.9% on Terminal-Bench 4.0).
• Context: 1 million token context window, up to 128k output tokens.
• Price: $4 / $20 per million tokens via the API.
• Modality: Text and image input, with adaptive thinking always on.

This guide is a starting point for your journey with Claude Opus.