Claude Haiku 5.5

Pelicans riding bicycles for Haiku at the different thinking levels: https://tools.simonwillison.net/markdown-svg-renderer?url=ht...

Low messes up the bicycle frame, but medium/high/xhigh/max all get the bicycle frame right.

The max one took 5 minutes 9 seconds and cost 3.3826 cents. The cheapest one (low) cost 0.0936 cents and took 7 seconds.

The most recent release of my llm-anthropic plugin queries the Anthropic model listing API directly, so I didn't have to upgrade the plugin to add support for this model:

  llm install llm-anthropic -U                                
  llm anthropic refresh
  llm -m claude-haiku-5.5 'prompt goes here'

Pricing is...a bit weird.

    Input
    $0.10 / MTok for prompts up to 100,000 tokens
    $0.50 / MTok for prompts over 100,000 tokens

    Output 
    $0.50 / MTok for prompts up to 100,000 tokens
    $2.50 / MTok for prompts over 100,000 tokens

In both cases, still much cheaper than Haiku 4.5's $1 input / $5 output and these prices better compete with GPT-6 Luna. ($0.10 input / $0.50 output, but with no token threshold [EDIT: the threshold for Luna is apparently 272k])

> Second, this week, we’ll roll out a new monthly API credit to all Max and Team subscribers for use on the Claude Platform. Max 5x users will get $100 in credits per month, Max 20x users will get $200, and Team subscribers will receive up to $500, pooled across their users

This is a very big benefit for me. I can now ship actual ai enhanced features behind my subscription without paying extra or fully relying on on-device models. I do worry that this is to soften the blow for user-unfriendly changes

My complaint about Haiku 4.5 was that it was 10x the price of GPT-6 Luna.

> Claude Haiku 5.5 is priced 90% lower than Claude Haiku 4.5 for requests up to 100,000 tokens, and 50% lower for requests over 100,000 tokens

Haiku and Luna now have the exact same price up to 100,000 tokens. Luna is now cheaper for anything after 100,000 tokens, even after Luna's own price increases at 270,000 it's still less than Haiku.

So it sounds like they've directly addressed that problem. Their self-reported benchmarks are all higher than Luna too.

Ran image -> html tests for this. I was curious if this smaller model was good enough for complex UI. It was not.

Haiku 5.5: https://html.non.io/lcars-haiku-5.5/

Opus 5.5 for comparison: https://html.non.io/lcars-opus-5.5

Designs it was building from: https://diffui.ai/app/canvas/5093e689-1e74-4f26-b632-2a4500f...

One interesting thing is it took a look at the job at hand, and immediately delegated it to Opus 5.5. It at least knows what it isn't good at. Very fast though, and likely best used for small subagent tasks / tightly scoped work.

The monthly API credits for Max plan seems fantastic, especially considering Haiku pricing. Being able to actually use my Claude plan for other harnesses and use-cases on top of regular CC usage is everything I wanted.

Anthropic has really been doing all the right things in the past few weeks, while OpenAI continues to fumble the bag.

Alright its still little early since there is not enough independent testing but this looks very promising and I wasn't expecting anthropic to beat GPT-6 Luna especially at the same price. Haiku 5.5 beats Luna on every shared benchmark Anthropic published, particularly computer use and agentic coding.

This is great! Been using GPT 6 Luna for decompiling my childhood favorite game (Age of Mythology) and this means I can throw Haiku into the mix as well. 17352/21965 functions matched so far...

About time Anthropic released a competitive cheap model. Haiku 4.5 has been too expensive compared to its performance for months now (in fact I don't remember being too impressed even when it was released). This one actually looks worth using in some scenarios. If it's really as much of a step up from Luna as the benchmarks they've shown indicate, it'll probably replace Luna in my workflows. 100k tokens is a pretty low threshold before the price goes up, but I tend to use these smaller models for smaller tasks anyway.

Finally! I understand Haiku is the less intelligent model, but the gap between Sonnet and Opus has been far too wide for about a year now.

At work we use haiku 4.5 for a handful of latency sensitive tasks that are fairly simple. It performs well. Just started testing 5.5 as I’ve been anticipating a nice improvement since it was teased. Results so far are trash. Prompt leakage even. And it’s slower. I guess it’s cheap but I think they got the balance wrong on this.

> Claude Haiku 5.5 is our fastest model to date at each model’s standard speed, although it runs less quickly than our Opus models in Fast Mode.

Opus 5.5 runs 117 tps average on Openrouter, so it must be at least 10-20 tps slower for them to mention. IDK why they mention this as it does not help for marketing though. https://openrouter.ai/anthropic/claude-opus-5.5

https://www.anthropic.com/claude-haiku-5-5#further-updates

This section makes the reader think: why would I not pick Sonnet 5.5 instead of Haiku 5.5?

I wonder if we have an AI LLM equivalent to Moore's Law. Like how often do we expect improvement in this technology and with what timing?

> we’ll roll out a new monthly API credit to all Max and Team subscribers for use on the Claude Platform. Max 5x users will get $100 in credits per month, Max 20x users will get $200

They’re definitely planning to make the subscriptions API based so they can charge you full price.

Top of the page in 17 minutes? Now I know what y'all do while your agents are working.

131tok/s P50 according to OpenRouter currently, though might move up or down over the coming days. If it sticks at that speed, roughly twice the throughput of Luna and far lower latency (up to 2sec depending on provider) is impressive, though the 5x price increase beyond 100k is painful.

Was a big fan of Haiku 4.5, though understand why for most Sonnet was the far better option back then.

Good to see Anthropic back alternative OSes.

> Second, this week, we’ll roll out a new monthly API credit to all Max and Team subscribers for use on the Claude Platform. Max 5x users will get $100 in credits per month, Max 20x users will get $200, and Team subscribers will receive up to $500, pooled across their users. These credits are designed to allow our users to experiment with building tools, apps, and agents that call our API.

This is kind of nuts

I am perpetually confused about every name and version combination from both OpenAI and Anthropic. Especially in conjunction with the effort levels.

From these selected benchmarks, it looks like it smokes Luna capability-wise. Excited to put it through its paces

The forgotten model is back on the map. I actually got OK mileage when I tried it for coding months ago. Maybe I'll try it again, with Opus guiding it, and see how it goes.

Apparently quite a bit smarter than Luna, I wonder what use cases it can cover. I actually honestly don't need a Haiku level AI to be that smart, and looks like you pay for it in the per token cost, I need speed mainly. I might even rather have a dumber but much faster model for things like web searching and parsing to retrieve results for the app or other LLM to do things with.

How are y'all using Haiku though? I rarely select it.

According to AA benchmarks, it uses 162k output tokens per task (with max reasoning) - over double GLM-5.3 Flash for similar level of Intelligence

no AA benchmarks yet and the last chart in the announcement makes Haiku look useless vs new Sonnet pricing, interesting to see what 3rd party benchmarks show because i think Anthropic are costpertaskmaxxing here and it's going to look more like that bottom chart than the top ones.

Seeing people talking about the Agents SDK -> credits change makes me wonder does it impact Zed or likes.

It’s about time Haiku got an update!

The important question though...how does it do making a pelican on a bicycle?

It's finally here ! Need to take a look at some benchmark now

It fails the "How many r's in <word>?" test.

I ask:

> how many r's in diminished

It answers:

> Diminished has 1 r.

Happy about the Sonnet cache read price cut.

How does the price compare to Luna? At least looking at the numbers it is noticeably better at most tasks.

Finally it has arrived.

> Second, this week, we’ll roll out a new monthly API credit to all Max and Team subscribers for use on the Claude Platform. Max 5x users will get $100 in credits per month, Max 20x users will get $200, and Team subscribers will receive up to $500, pooled across their users. These credits are designed to allow our users to experiment with building tools, apps, and agents that call our API. They can be used on any of our models. For more information, see our Help Center article.

Did anyone read this? We get free API credits on some plans now

Wow, the rate of improvements in the AI era is staggering.

GDPval-AA v2.1 as of now: 1620

GDPval-AA v2.1 for Haiku 4.5: 735

The 100k tokens pricing makes sense, looks to be a hedge against OpenAI's decisions API and Jev or its open source alternatives that are springing up.

Nice release, congrats to Anthropic.

Begging Anthropic to let us use Claude subs with harnesses other than Claude Code at this point.

will use it to replace luna in production !

The important question is, does it talk in incomprehensible Claude-ese like the other Claude 5.x models?

Where is Pelican? ehehhe

I remember a friend asking me why LLMs suck so bad. She was using Haiku 4.5 and that poor model couldn't keep track of the context within 3 messages.

She said she was using Haiku 4.5 because she was advised to be careful with the spending.

I hate that model so much lol.

Probably the same scam as the last Haiku update I guess. Uses more tokens to compensate for the lower price.

    > but they still block penetration testing and other techniques more likely to be used by attackers.
    > 
    > Haiku 5.5’s biology safeguards are the same as for Sonnet 5, Sonnet 5.5, and Opus 5. They allow research biology questions but restrict access to requests that we judge as likely to cause harm. Organizations working on wider-ranging biology and cyber activities can apply to our Life Sciences Verification Program and Cyber Verification Program.

These are the examples from "Detecting and countering misuse of AI: September 2026" - https://news.ycombinator.com/item?id=49647300

    > Importantly, because our biological safety classifiers robustly block content involving high-risk biological research (in this case, the construction of enhanced pandemic potential pathogens), all of these exchanges occurred on models in our weakest class of models (specifically, the models were Claude Sonnet 4 and Haiku 4.5, the latter of which the user began using after Sonnet 4 was deprecated). 
    >
    > Upon a detailed examination of the exchanges, we estimate that the uplift provided by Claude was primarily clerical assistance in data analysis, study ideation and design. This is consistent with our understanding of the capabilities of Sonnet 4 and Haiku 4.5, which are not able to perform expert-level biology research tasks; we estimate that the uplift provided to the researcher was limited and substantially lower than it would have been from one of our more capable models.

While doing my best to avoid comment, please note, they're talking about a domain expert in a state research institution using Claude to do paperwork.

What did they save us from? What bioweapons did these filters prevent? From the front matter report,

    > The above LLM platform is not the only route via which researchers engaged in viral gain-of-function research have used our platform. In May 2026, we discovered a researcher outside the US using Claude in their research on highly-pathogenic avian influenza (“bird flu”). The research focused on viruses’ adaptation to mammals, and the mechanism by which it causes severe disease beyond the respiratory tract.

    > The researcher pursued this work in a credible institutional context, and interacted with Claude over the course of several weeks, exchanging thousands of messages. In these exchanges, the researcher leveraged Claude’s knowledge of the scientific literature to assist the researcher in study planning and design, data analysis, and the interpretation and prioritization of experiments. The researcher also used Claude for editorial assistance in writing up the research.

What "uplift" are you providing to scientists working at specialized global BSL-4 labs that already have – and I quote their report - "physical access to such isolates." (as in samples of viruses)? Are we uplifting their grammar?

These "safeguards" are being expanded. The scientists I know can't use Claude for grammar checks or anything serious. You can try it for yourself.

> Haiku 5.5’s cybersecurity safeguards are more restrictive than Haiku 4.5’s, but somewhat less restrictive than those we’ve applied to other recent models. In cybersecurity, they permit a wider range of defensive tasks than our safeguards for Sonnet 5.5, but they still block penetration testing and other techniques more likely to be used by attackers.

If you block pentest or "other techniques more likely to be used by attackers", then what does "permit a wider range of defensive tasks" even mean?

Any defensive task that's meaningful is almost indistinguishable from legitimate red-teaming that then falls under 'likely to be used by attackers". If only they would just stop nerfing these models, that'd be great. No APT is waiting around for Anthropic's permission, so might as well let us have some cool stuff.

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Does anyone still use Haiku model?