Anthropic ships Sonnet 5.5: a third faster at the same price
A same-price, faster and cheaper mid-tier model resets the default for agent workloads, though the numbers remain Anthropic's own.
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Anthropic released Claude Sonnet 5.5 on September 28, keeping API pricing flat with the previous generation while generating output more than 30% faster.
Pricing stays at $2 per million input tokens and $10 per million output tokens; Anthropic's testing puts the cost of the same task up to 30% below Sonnet 5. On Anthropic's own Terminal-Bench 4.0 agentic coding evaluation, Sonnet 5.5 scores 70.6% against Sonnet 5's 10.3%.
Early testers report it batches tool calls together more often than Sonnet 5, cutting steps. Anthropic itself notes that Opus 5.5 remains clearly stronger on complex, open-ended work requiring sustained judgment. This is the first Sonnet to launch with cybersecurity safeguards built in.