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.
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.
Sources:https://www.anthropic.com/claude-sonnet-5-5https://www.leiphone.com/category/ai/eFLQ0PfFrKc5kRSs.html