Model · 2026-10-07

Claude Haiku 5.5

As previously promised, here's Anthropic's new fast, low cost model: Introducing Claude Haiku 5.5. The previous Haiku, 4.5, was very much showing its age. It came out almost a year ago, and was priced at $1/million input and $5/million output - relatively exp…

Simon Willison Blog2026-10-07About 3 min readWorth tracking

Marked important, but published more than 30 days ago, so it moved down to this band.

Frontier modelsPricing & cost
On this page12 sections

The editors' notes below — why it matters, the context, the learning path — are written in Chinese.

Record

The signal

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As previously promised, here's Anthropic's new fast, low cost model: Introducing Claude Haiku 5.5. The previous Haiku, 4.5, was very much showing its age. It came out almost a year ago, and was priced at $1/million input and $5/million output - relatively expensive even back then, and a full 10x the price of OpenAI's GPT-6 Luna, released last month. The new Haiku exactly matches the price of GPT-6 Luna - $0.10/$0.50 - up to 100,000 tokens. Beyond 100,000 tokens the price increases 5x to $0.50/$2.50. Luna itself has a price increase at 272,000 tokens but only to $0.20/$0.75. Haiku 5.5 also uses a new, less generous tokenizer. My Claude Token Counter tool shows that the same long prompt uses around 1.25x as many tokens with Haiku 5.5 compared to Haiku 4.5, so there's a hidden price increase there. If your workloads fit in 100,000 tokens, Haiku is the same price as Luna and reports higher benchmark scores. Above 100,000 tokens, Luna looks like a much better deal. The most recent release of llm-anthropic finally fixed it so I don't need to ship a new version of that plugin for every new model. I tested the new model like this: llm install -U llm-anthropic llm anthropic refresh llm -m claude-haiku-5.5 "Generate an SVG of a pelican riding a bicycle" -o thinking_effort low Pelicans Here are pelicans for low, medium, high, xhigh, and max. The new Haiku doesn't let you disable reasoning, and defaults to medium. I got a good bicycle frame for everything beyond low. The low effort pelican cost 0.0936 cents and took 7 seconds. This max effort pelican (with a reasoning trace that start…

Why now

Why it matters

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最便宜的一档第一次在操作电脑和终端任务上有了可用的成绩,子智能体、批量摘要这类调用的成本结构会跟着变。但新分词器和关不掉的推理意味着账单不会按标价降九成,要按自己的提示重新算。

Background

Technical context

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Anthropic 的模型按档位分为 Fable、Opus、Sonnet 和 Haiku,Haiku 是最便宜、最快的一档。分词器决定一段文字被切成多少 token,换分词器后同样的文字可能计费更多。推理档位越高,思考 token 越多,而思考 token 按输出计费。

At your level

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Audience

Who should care

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用小模型做分类、摘要、子任务分发的工程团队负责模型路由、在 Haiku 与 Sonnet 之间分配流量的平台团队处理长文档、提示常超过 10 万 token 的应用
Areas it may affect
模型选型推理成本子智能体

Next

Learning path

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  1. 先读本站 9 月 28 日的 Claude Sonnet 5.5 信号,看同一代里上一档的成绩与价格
  2. 读《模型选型与约束匹配》,想清楚哪些调用真的需要大模型
  3. 拿自己的 20 条典型提示,分别统计 Haiku 4.5 与 5.5 的 token 数与费用
  4. 读《推理服务容量规划》,把推理档位带来的延迟下限算进容量

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Network

Where it sits in the network

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Further thought

Follow-up questions

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  • 你的提示里有多少超过 10 万 token?按分段价算,实际单价是多少?
  • 换成 Haiku 5.5 后,同样的提示 token 数变了多少?
  • 哪些子任务可以从 Sonnet 下放到 Haiku 5.5?用什么指标判断没有变差?

Publication record

Featured in

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The briefings that carried this signal, newest first; the last row is the weekly review of its week. The tag is the section it ran in.

  1. 技术简报 - 2026-10-08

    Immediate attention

Sources

Simon Willison Blog

AnthropicBig tech2026-10-07
Open original sourcehttps://simonwillison.net/2026/Oct/7/claude-haiku-5-5/