Anthropic releases Claude Haiku 5.5, a small model
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In October 2026, Anthropic released Claude Haiku 5.5, calling it the fastest, cheapest, and most capable small model to date. This model is the first in the Haiku tier to introduce adjustable effort settings and adaptive thinking, supports a 1 million token context, and uses tiered pricing: $0.10/$0.50 per 1M input/output tokens for up to 100,000 tokens, and $0.50/$2.50 beyond 100,000. The company says overall average operating costs are about 75% lower than Haiku 4.5. The Artificial Analysis intelligence index scores 43 at the highest reasoning tier. The System Card reports that RSP evaluations did not cross the CB-2 or Autonomy-2 thresholds, but did reach the CB-1 and Autonomy-1 thresholds, and corresponding mitigations were applied. Official benchmarks say OSWorld 2.1 reaches 72.4% at the Max tier, but Terminal-Bench 4.0 scores only 39.2%, below Sonnet 5.5's 70.6%. Anthropic still recommends larger models for complex tasks. On safety, in Claude Code testing, the refusal rate for malicious requests rose from 66.6% for Haiku 4.5 to 84.3%, and cybersecurity guardrails are more lenient than Sonnet 5.5's.
Generated by AI from reports · Updated 2 days ago
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- AI 科技评论Behind Claude Haiku 5.5's cost reduction: big gains in agentic ability, but complex coding still trails Sonnet 5.5
Anthropic releases Claude Haiku 5.5; its OSWorld 2.1 score rises from 15.7% in the previous generation to 72.4%, and average operating costs drop by about 75%. The new model introduces Adaptive Thinking and Effort strength settings to the Haiku line for the first time, and supports a 1 million token context. However, it scores only 39.2% on Terminal-Bench 4.0, far below Sonnet 5.5's 70.6%; Anthropic still recommends Sonnet 5.5 or Opus 5.5 for complex agent coding tasks.
- Help Net Security AIAnthropic Claude Haiku 5.5 release: prompt injection resistance significantly improved
Anthropic releases Claude Haiku 5.5, calling it the Haiku model with the strongest prompt injection resistance to date; in adaptive attack tests in coding and computer-use environments, its resistance roughly matches its frontier models. In Claude Code tests, the model's refusal rate for malicious requests rises from 66.6% with Haiku 4.5 to 84.3%, and in computer-use scenarios the refusal rate rises from 58.9% to about 82.6%. Its cybersecurity guardrails are stricter than Haiku 4.5's but looser than recent models like Sonnet 5.5; qualified security practitioners can apply for relaxed limits through the Cyber Verification Program.
- RedditReddit r/Anthropic· DiscussionClaude Haiku 5.5 just dropped and the price is probably more interesting than the model itself(opens the original post in a new tab)
- 量子位Claude Haiku 5.5 released: surpasses GPT-6 Luna in every benchmark, priced to match and lower than DeepSeek-V4.1 Flash
Anthropic released Claude Haiku 5.5, whose official benchmarks beat GPT-6 Luna on every item, and surpassed DeepSeek-V4.1 Flash and GLM-5.3-Flash to become the new small-model gatekeeper. It is the first Haiku to support five effort tiers. On OSWorld 2.1, the Max tier reaches 72.4% accuracy at a per-run cost of $0.61, while Haiku 4.5 reached only 15.7% at $1.45. Prices for input and output drop 90% for requests under 100,000 tokens, but the new tokenizer uses more tokens for the same task. Terminal-Bench 4.0 scores only 39.2%, far below Sonnet 5.5's 70.6%.
- X @MinLiBuildsAnthropic releases Claude Haiku 5.5, priced 90% lower than Haiku 4.5
Anthropic releases Claude Haiku 5.5, with input at $0.10, output at $0.50, and cache read at $0.01 per 1M tokens for tasks with ≤100K prompt, a 90% price cut from Haiku 4.5's $1/$5/$0.10; beyond 100K it is $0.50/$2.50, and the company says overall average running costs are about 75% lower. Official benchmarks show OSWorld 2.1 at 72.4% (GPT-6 Luna 48.9%), Terminal-Bench 4 at 39.2% (16.4%), FrontierCode 1.1 at 46.4% (42.4%), and GDPval-AA at 1620 (1437). This model is the first Haiku to support adjustable effort settings; the company recommends Opus/Sonnet as lead agent and Haiku as subagent.
- XX @haider1· DiscussionWTF is going on with Haiku 5.5(opens the original post in a new tab)
- XX @bcherny· DiscussionHaiku 5.5 is a good Haiku.(opens the original post in a new tab)
- XX @rohanpaul_ai· DiscussionAnthropic dropped Haiku 5.5(opens the original post in a new tab)
- RedditReddit r/Anthropic· DiscussionHaiku 5.5 Released before Announcement(opens the original post in a new tab)
- RedditReddit r/Anthropic· DiscussionAnthropic launches Haiku 5.5, says it costs 75% less to run(opens the original post in a new tab)
- RedditReddit r/Anthropic· DiscussionHaiku 5.5 is out(opens the original post in a new tab)
- RedditReddit r/Anthropic· DiscussionIntroducing Claude Haiku 5.5: the cheapest, fastest, and most capable small model we’ve ever released(opens the original post in a new tab)
- Hacker NewsHacker News· DiscussionClaude Haiku 5.5(opens the original post in a new tab)
- RedditReddit r/Anthropic· DiscussionHaiku 5.5 is released(opens the original post in a new tab)
- AnthropicAnthropic releases Claude Haiku 5.5: the fastest and cheapest small model
Anthropic releases Claude Haiku 5.5, calling it its fastest, cheapest, and most capable small model to date, with average operating costs about 75% lower than Haiku 4.5. The model targets high-concurrency, cost-sensitive tasks, can serve as a subagent for Opus 5.5 and Sonnet 5.5, and introduces adjustable effort settings to the Haiku tier for the first time. On safety, its alignment evaluations show substantial improvements over Haiku 4.5; its cybersecurity guardrails are looser than Sonnet 5.5's but still block penetration testing, and its biosecurity guardrails match those of Sonnet 5, Sonnet 5.5, and Opus 5.
- artificialanalysis.aiArtificial Analysis: Haiku 5.5's highest reasoning tier scores 43 on the Intelligence Index
Anthropic released Claude Haiku 5.5, scoring 43 on the Artificial Analysis Intelligence Index, a 26-point improvement over the previous Haiku a year after its release. This is the first Haiku model to support effort settings and adaptive thinking, and introduces tiered pricing: $0.10/$0.50 per 1M input/output tokens for requests under 100k tokens, rising to $0.50/$2.50 above 100k. Its context window increased from 200k on Claude 4.5 Haiku to 1M tokens, and Terminal-Bench 4.0 scores rose from 0% to 33%, but the AutomationBench-AA score of 35% may be underestimated due to safety refusal issues.
- Anthropic ResearchSelectedAnthropic releases Claude Haiku 5.5 System Card
Anthropic releases the System Card for Claude Haiku 5.5, reporting pre-deployment evaluation results across seven areas: RSP, cybersecurity, guardrails and helpfulness, agent safety, alignment, model welfare, and capabilities. RSP evaluations show Haiku 5.5's overall capabilities are below Claude Opus 5, and it does not cross the CB-2 or Autonomy-2 thresholds, but it does meet the CB-1 and Autonomy-1 thresholds and applies the corresponding mitigations. On cyber capabilities, it is notably stronger than Haiku 4.5 but weaker than Opus 5.5, Claude Mythos 5.1, and even Opus 5, so its cyber guardrails trigger on a narrower range than other recent releases. Agent safety evaluations call it the most robust Haiku-tier model against prompt injection to date, with robustness approaching frontier models against adaptive attackers in coding and computer-use environments. The model's knowledge cutoff is June 2026.
Related discussion
- Older than 72 hours · Not included in the 72-hour figures
- 网页新智元Just now, Claude Haiku 5.5 released! Price drops 90%(opens the original post in a new tab)
- XX @arenaReal-world results are in for Claude Haiku 5.5 (High) by @AnthropicAI.(opens the original post in a new tab)
- RedditReddit r/AnthropicClaude Haiku 5.5 just dropped and the price is probably more interesting than the model itself(opens the original post in a new tab)
- 网页开源中国 · 资讯Claude Haiku 5.5 is here: price cut to a quarter, agent capability jumps from 0 to 39%(opens the original post in a new tab)
- 网页cnBetaAnthropic releases Claude Haiku 5.5: prices cut significantly, but the new tokenizer consumes more tokens(opens the original post in a new tab)
- 网页智东西Claude's strongest mini model arrives, price drops 90%, closing in on DeepSeek?(opens the original post in a new tab)
- 网页SiliconANGLE · AIAnthropic releases Claude Haiku 5.5 small model and halves Sonnet 5.5 cache read prices(opens the original post in a new tab)
- 网页IT之家Anthropic's fastest, cheapest model: Claude Haiku 5.5 debuts, with running costs about 75% lower than 4.5(opens the original post in a new tab)
- XX @haider1WTF is going on with Haiku 5.5(opens the original post in a new tab)
- XX @bchernyHaiku 5.5 is a good Haiku.(opens the original post in a new tab)
- XX @arenaClaude Haiku 5.5 by @AnthropicAI is now in the Arena. Head to Agent Arena to test it out, scores coming soon!(opens the original post in a new tab)
- 网页TechmemeAnthropic prices Haiku 5.5 at $0.10/1M input and $0.50/1M output tokens for requests up to 100K tokens, and $0.50 and $2.50 above, vs. $1 and $5 for Haiku 4.5 (Frederic Lardinois/The New Stack)(opens the original post in a new tab)
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