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Latest / Frontier models and safety

Model releaseFrontierUSConfirmed

Anthropic releases Claude Sonnet 5.5 with cyber safeguards from its top models

See how this story connects

Source: Anthropic: Introducing Claude Sonnet 5.5

Anthropic released Claude Sonnet 5.5, priced like Sonnet 5 at $2 and $10 per million input and output tokens, which it says runs more than 30% faster and costs up to 30% less per task. It scored 70.6% on Terminal-Bench 4.0 against Sonnet 5’s 10.3%. Anthropic said its cyber capabilities are comparable to Opus 5’s, so it is the first Sonnet model to launch with cyber safeguards and fallbacks.

Why it matters

Teams using the mid-priced Claude model get near-Opus scores on several benchmarks, and some cyber requests now hit the same blocks as Anthropic’s top models.

When
28 Sep 2026
ID
WTA-N-2026-0133
Who
Anthropic

Summary by wheresthe.ai, from Anthropic. Checked against the source on 9 Oct 2026.

Read the original at Anthropic

Source copy: download the page as saved on 18 Oct 2026 (PDF). Also held by the Internet Archive.

Next stop on this Storyline: What happened nextAnthropic releases Claude Haiku 5.5 and halves Sonnet 5.5 cache-read prices

Cite this story

WTA-N-2026-0133: “Anthropic releases Claude Sonnet 5.5 with cyber safeguards from its top models.” wheresthe.ai, 28 Sep 2026. https://wheresthe.ai/d/anthropic-claude-sonnet-5-5-release-2026-09/ (source: Anthropic: Introducing Claude Sonnet 5.5).

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