Anthropic has introduced Claude Opus 5.5, the newest model in its Claude 5.5 family. The company says it improves agentic coding, computer use, knowledge work and long-horizon tasks while costing less than Claude Opus 5.
What changed
Opus 5.5 is designed for large codebases, migrations, automation and workflows that combine multiple tools. Anthropic also reports stronger resistance to prompt injection.
- Terminal-Bench 4.0: 66.4%
- FrontierCode v1.1: 54.4%
- Humanity’s Last Exam with tools: 67.7%
Cost and speed
API pricing is $4 per million input tokens and $20 per million output tokens. Cache reads cost $0.20 per million tokens. Anthropic says typical workloads cost about 40% less and output is generated more than 30% faster than with Opus 5.
Published examples include a 680,000-line code migration completed in less than a day and a C-to-Rust rewrite of HAProxy completed in 9.5 hours. These are company and early-tester results.
Why it matters
When a model can work for a long time with code, tools and tests, cost, speed and safety become part of its practical capability. Claude Sonnet 5.5 and Claude Haiku 5.5 are expected in the coming weeks.
Source: Anthropic’s official announcement.