GoKawiilAnthropic launches Claude Sonnet 5.5, faster and cheaper than Sonnet 5
Anthropic released Claude Sonnet 5.5, the second model in its Claude 5.5 lineup after Opus 5.5. The company says it runs over 30% faster and costs up to 30% less per task than Sonnet 5, while keeping the same per-token pricing, and jumps from 10.3% to 70.6% on the Terminal-Bench 4.0 agentic coding evaluation. A third model, Claude Haiku 5.5, is planned for release in the coming weeks.
GoKawiil's interpretation of the reporting above, not reported fact.
Positioning Sonnet 5.5 as a cheaper, quicker complement to Opus 5.5 suggests Anthropic is trying to cover both high-end reasoning tasks and everyday, high-volume work with one family of models. The token-efficiency gains, rather than price cuts, indicate Anthropic's strategy for lowering costs may rely on making models do more with less rather than discounting rates. Matching Opus-level cybersecurity safeguards in a lower-cost model could also signal broader efforts to manage misuse risks as capabilities spread across cheaper tiers.
- Sonnet 5.5 is 30%+ faster and up to 30% cheaper per task than Sonnet 5, at unchanged token pricing.
- It scores 70.6% on Terminal-Bench 4.0, up sharply from Sonnet 5's 10.3%, and trails Opus 5.5 by only two points on GDPval-AA.
- A third model, Claude Haiku 5.5, aimed at high-volume, cost-sensitive use, is expected within weeks.
Source: anthropic.com, 2026-09-28
Published there as: “Claude Sonnet 5.5”
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