Key Info

Claude Opus 5.5, the first model in Anthropic's new Claude 5.5 family, is now available on API and Web Chat, delivering performance comparable to Claude Fable 5.1 on most tasks while costing about 40% less to run than Opus 5.

Highlights

  • Supports 1M token context window and up to 128K output tokens.
  • Optimized for long-running agentic coding and complex knowledge work.
  • Demonstrates leading capabilities in Computer Use and multi-step automation.
  • Available on both API and Web Chat interfaces.