Anthropic's Claude Sonnet 5.5 nearly matches Opus 5.5 on benchmarks while costing up to 30 percent less per task
Claude Sonnet 5.5 is a fast, cost‑efficient model that rivals Opus 5.5. It delivers 30% faster output and 30% lower per‑task cost, hitting 70.6% on Terminal‑Bench. Anthropic plans Haiku 5.5 soon, matching OpenAI’s GPT‑6 lineup.