Story perspectives

Anthropic Releases Claude Sonnet 5.5, Faster and Cheaper

By Drooid · Sep 28, 2026, 10:36 PM UTC · How we work

Summary

Story summary

Anthropic released Claude Sonnet 5.5, a faster, lower-cost AI model, on September 15, 2026.
Sonnet 5.5 runs over 30% faster and costs up to 30% less per task than Sonnet 5.
It achieved 70.6% on Terminal-Bench 4.0 coding test, surpassing Sonnet 5’s 10.3%.
Sonnet 5.5 includes cyber safeguards and classifiers that block reasoning extraction, matching Opus 5 safety level.

History

Historical Context

In February 2019 OpenAI announced GPT-2, a 1.5-billion-parameter model whose staged release sparked debate over misuse and prompted early AI-safety research. That debate fed into the EU’s 2024 AI Act and set expectations for later systems. On 15 September 2026 Anthropic launched Claude Sonnet 5.5, delivering 30 % faster inference and 30 % lower cost while embedding safeguards reminiscent of those early concerns.

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Story summary

Anthropic released Claude Sonnet 5.5, a faster, lower-cost AI model, on September 15, 2026.
Sonnet 5.5 runs over 30% faster and costs up to 30% less per task than Sonnet 5.
It achieved 70.6% on Terminal-Bench 4.0 coding test, surpassing Sonnet 5’s 10.3%.
Sonnet 5.5 includes cyber safeguards and classifiers that block reasoning extraction, matching Opus 5 safety level.

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