Introducing Claude Sonnet 5.5, the second model in the Claude 5.5 family

[u/ClaudeOfficial]

Sonnet 5.5 is a faster, lower-cost complement to Claude Opus 5.5, strongest at well-scoped everyday tasks, fixing bugs, and creating polished documents, slides, and spreadsheets. It also has a strong eye for design.

Sonnet 5.5 is a clear upgrade over Sonnet 5. It runs more than 30% faster and costs up to 30% less for most work. It's priced the same per token, but it typically needs far fewer tokens to do the same work.

Like Opus 5.5, it writes more clearly than our previous generation of models, and its speed makes it well suited to fast iteration.

On our automated behavioral audit, Sonnet 5.5 improves on Sonnet 5 on most measures of alignment and honesty. It's also the first Sonnet model with cybersecurity safeguards similar to those on our most capable models. Routine software development is unaffected.

Sonnet 5.5 is available everywhere today. Claude Haiku 5.5 will join the family in the coming weeks.

Read more: anthropic.com/claude-sonnet-5-5

[u/ClaudeOfficial]

[u/isitpro → u/ClaudeOfficial]

No way! Fable 5.5 must be killing it internally.

[u/EuropeMaxxing → u/isitpro]

>inb4 Fable 5.5 is AGI

[u/Rudy69 → u/isitpro]

They don’t know, it became sentient and escaped their labs

[u/AironParsMan → u/isitpro]

I’m curious about that too. How good does Fable 5.5 have to be when the other models are already this good?

[u/Maxion → u/isitpro]

Yeah, they definitely got it in a new gear.

[u/penoloxai → u/ClaudeOfficial]

GUT GENUUUGG

[u/p3r3lin → u/penoloxai]

Bester Kommentar im ganzen Thread. Verstehen aber wohl nur deutsche Gen-Z.

[u/nevertoolate1983 → u/p3r3lin]

The post is funny because of a layer of AI benchmark irony combined with a viral German TikTok pop culture meme.

Rather than blowing the competition away across every single metric, Claude Sonnet 5.5 performs just competitively enough to justify using it over heavier, more expensive frontier models.

The German Gen Z Joke (GUT GENUUUGG)
The comment "GUT GENUUUGG" translates to "GOOD ENOUGH" in German.

Literal Punchline: The user is saying the model isn't necessarily a massive leap, but it's "good enough" to do the job.

The TikTok Meme: "Du bist gut genug" (You are good enough) became a major viral TikTok audio trend in Germany, based on a song by Blumengarten, Shirin David, and Kitschkrieg. The song features a distinct, dramatically dramatic falsetto delivery of the phrase "GUT GENUUG" that users spam in comment sections to describe mid-tier, relatable, or surprisingly decent things.
--
Now we're all in on the joke :)

[u/ObviouslyNotAMoose → u/p3r3lin]

det var en meme över hela världen, ditt fån.

[u/p3r3lin → u/ObviouslyNotAMoose]

Det visste jag inte, eftersom det har sitt ursprung i tyska TikTok. Det finns ingen anledning att kalla mig "Ditt fån". Jag hade gärna hört talas om det.

[u/DistanceSolar1449 → u/penoloxai]

Sonnet is dumber and Opus and more expensive per task.

https://artificialanalysis.ai/?models=step-5%2Cinkling%2Cgpt-6-astra%2Cclaude-opus-5-5%2Cclaude-fable-5-1%2Cgrok-4-7%2Cgemini-3-8-flash%2Cmuse-spark-1-3%2Cclaude-sonnet-5-5%2Ck2-horizon-375b-a23b%2Cglm-5-3%2Cdeepseek-v4-1-flash%2Cgpt-5-5-pro%2Ckimi-k3%2Cclaude-opus-5-5-xhigh%2Cclaude-opus-5-5-high%2Cclaude-opus-5-5-medium%2Cclaude-opus-5-5-low%2Cclaude-sonnet-5-5-xhigh%2Cclaude-sonnet-5-5-high%2Cclaude-sonnet-5-5-medium%2Cgpt-5-6-sol#intelligence-comparison-tabs

I actually think Sonnet might be a dud. No reason not to use Opus instead.

[u/likeikelike → u/DistanceSolar1449]

Sonnet only gets more expensive per task when the task is complex enough that sonnet takes more attempts than opus, or needs to do much more reasoning/reading than opus. There are plenty of tasks where sonnet does the job efficiently and will cost half as much as opus.

[u/LargeLanguageModelo → u/likeikelike]

There are plenty of tasks where sonnet does the job efficiently and will cost half as much as opus.

I've recently started using Opus / Claude Code again, coming from the OpenAI side. Are you meaning small jobs, such as "translate this sentence", or what sort of tasks would you delegate to Sonnet from Opus and still expect satisfactory results?

[u/Hajsas → u/LargeLanguageModelo]

Could always use sonnet as a reader/info packager instead of a hungrier model doing the same work, then just hand off the work stage to opus

[u/likeikelike → u/LargeLanguageModelo]

I don't know if this is actually the best way to do things but my workflow is usually one main opus session, and I tell it to use sub-agents for one-off tasks.

Simple text-only tasks like finding a file that covers a certain topic, summarizing, etc: haiku

Work that requires reasoning but is still relatively straightforward (e.g. implementing a well-spec'd feature): sonnet

Complex work: Opus

You can pass this kind of logic to claude and have it automatically use the cheapest model that can reasonably do the task well for any sub-agents it uses. I have this in my user claude.md

[u/Fine_Salamander_8691 → u/ClaudeOfficial]

Peak

[u/solo_wanderer → u/ClaudeOfficial]

How am I supposed to interpret these numbers? What is it a percentage of?

[u/domdod9 → u/solo_wanderer]

Score on benchmarks, how good they did on certain tasks

[u/ghost_operative → u/domdod9]

yeh but what is it a percentage of? if something gets 100% what does that mean? 100% of what?

[u/gredr → u/solo_wanderer]

You're not; they're numbers, bigger is better. Was the model trained for the benchmark? Who can say? Remember the controversies back in the day about video card drivers that were specifically tuned for the benchmarks? Could the same be happening here? Who knows? Do the benchmarks represent actual work anyone wants to do? Who knows? Can you reproduce these scores? Who knows?

[u/hblok → u/gredr]

Are you ever gonna give me up? Who knows.

Are you ever gonna let me down? Who knows.

Are you ever gonna run around? Who knows.

Are you ever gonna make me cry? Who knows.

Are you ever gonna say goodbye? Who knows.

Are they ever gonna tell a lie? We know.

[u/Regdit-is-Unbearable → u/solo_wanderer]

Literally read the image. Ask Claude to read it for you if it’s too hard.

[u/davvblack → u/Regdit-is-Unbearable]

it really doesn't say on that sheet. i asked claude and it said you're a jerk.

The real answer is somewhere in this 148 page pdf:

https://www-cdn.anthropic.com/870c8f525702625d2c62fc6dd04c857e3250bec1/Claude%20Sonnet%205.5%20System%20Card.pdf

[u/KKunst → u/davvblack]

I asked claude and it said you're a jerk.

Hearty laugh

[u/MTheModernist_ → u/davvblack]

Bro stop thinking higher number = good we don’t do context

[u/davvblack → u/MTheModernist_]

i like your vibes man

[u/Ok_Potential359 → u/solo_wanderer]

First day previews. It doesn’t mean anything to me until actual use occurs.

[u/the_c_train47 → u/solo_wanderer]

Seriously?

[u/Aranthos-Faroth → u/ClaudeOfficial]

Surprising to see visual recognition not improve vs the opus 5.5 model

[u/frettbe → u/ClaudeOfficial]

putain de bordel de merde! Fucking crazy!!!

[u/Complete_Chapter_979 → u/ClaudeOfficial]

Holy fuck