Anthropic Efficient Available in FlowHunt

Claude Haiku 5.5

Claude Haiku 5.5 is an Efficient-tier AI model developed by Anthropic and released on October 7, 2026. It is a proprietary closed-weight model, available on the Claude Platform and on Amazon Web Services, Google Cloud and Microsoft Azure. The 1M-token context window is large enough to hold entire codebases, lengthy technical documents, or extended agentic sessions without truncation.

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Anthropic calls Haiku 5.5 the cheapest, fastest and most capable small model it has released, and says it costs far less to run than Haiku 4.5 on average. It is built for quick, repetitive work such as summaries, compactions, database queries and classification, and for speed-sensitive uses like live customer support and browser use. It also pairs with Opus 5.5 and Sonnet 5.5 as a subagent on coding work. Haiku 5.5 is the first Haiku-class model with an adjustable effort setting, so you can trade cost against intelligence. Its cybersecurity safeguards are more restrictive than Haiku 4.5’s but permit more defensive work than Sonnet 5.5’s.
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Benchmarks

Each score appears once, with its rank among tracked models and who measured it.

Compared with Efficient peers on the same scale
  • Claude Haiku 5.5this model
  • Qwen3.8-27Bthis model leads on 4 of 4
  • Gemini 3.5 Flash-Litethis model leads on 3 of 3
Verified independent evaluator, counted in the ranking Self-reported published by Anthropic, shown but not ranked
Overall

AA Intelligence Index

Independent composite of agent, coding, knowledge and science tests by Artificial Analysis (v4).

Source ↗

Claude Haiku 5.5 43.4 Qwen3.8-27B 33.7 Gemini 3.5 Flash-Lite 22.2
#14of 45 Verified
Coding

SWE-bench Pro

Real issues across several languages and large codebases.

Source ↗

Claude Haiku 5.5 64.8% Qwen3.8-27B 61.7% Gemini 3.5 Flash-Lite No score
Not ranked Self-reported
Agents

Terminal-Bench 4.0

Multi-step professional tasks done by an agent in a command-line terminal.

Source ↗Also: Self-reported 39.2% (safeguards on; launch page https://www.anthropic.com/claude-haiku-5-5)

Claude Haiku 5.5 32.8% Qwen3.8-27B 5.6% Gemini 3.5 Flash-Lite 1.0%
#12of 36 Verified
Reasoning

Humanity's Last Exam

Expert-written questions across 100+ subjects, no tools.

Source ↗Also: Self-reported 45.9% (no tools)

Claude Haiku 5.5 44.4% Qwen3.8-27B 33.9% Gemini 3.5 Flash-Lite 18.8%
#15of 44 Verified

What to Use Claude Haiku 5.5 For

High-Volume Processing

Use it for repetitive, cost-sensitive workloads such as summaries, compactions, database queries and classification requests.

Subagent for Coding Work

It pairs with Opus 5.5 and Sonnet 5.5 as a subagent, handling smaller delegated tasks while a larger model plans and decides.

Live Support & Browser Use

Because it is Anthropic's fastest model to date, it suits speed-sensitive tasks such as live customer support and browser use.

Document Q&A at Scale

With a 1M-token context window and low cost per call, it fits high-volume question answering over documents.

Strengths and limitations

Strengths

  • Low cost per task compared with Haiku 4.5
  • Fast responses for live and interactive use
  • First Haiku-class model with an adjustable effort setting
  • Quick, repetitive work such as classification and summaries
  • Very long documents and large codebases (1M context)

Limitations

  • Closed-weight, so it cannot be self-hosted or fine-tuned on private data
  • Cybersecurity safeguards block penetration testing and other techniques more likely to be used by attackers
  • Built for volume work; Sonnet 5.5 and Opus 5.5 are the choice for complex, open-ended tasks

Use it in FlowHunt

Use Claude Haiku 5.5 in any flow, next to your own tools and knowledge sources.

  1. 1Open a flow, or create one from a template
  2. 2Add an AI Agent or Generator component
  3. 3Pick Claude Haiku 5.5 in the model selector

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About Anthropic San Francisco, CA · Founded 2021 · anthropic.com

Anthropic is an AI safety company founded in 2021 by former OpenAI researchers Dario Amodei and Daniela Amodei, along with a group of colleagues who had led OpenAI's safety and policy teams. The company's stated mission is the responsible development of AI for the long-term benefit of humanity, and its research agenda is defined by that commitment: Constitutional AI (CAI), a technique for training models to be helpful, harmless, and honest through self-critique; mechanistic interpretability, which aims to reverse-engineer what individual neurons and circuits inside large networks actually compute; and scaling science, which tries to predict how model behaviour changes with compute and data. Anthropic publishes this research openly and has become one of the most cited AI safety labs in academic literature. Claude is Anthropic's public model family, named for Claude Shannon, the founder of information theory, and runs from Claude 1 to the Claude 5.5 generation and Claude Fable 5.1. Anthropic operates a commercial API and consumer-facing Claude.ai product, and maintains deep cloud partnerships with AWS (Amazon Bedrock) and Google Cloud (Vertex AI).

anthropic.com ↗

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Frequently asked questions