Anthropic releases Claude Opus 5.5

techSep 22, 202661215

Anthropic released Claude Opus 5.5, the first model in its Claude 5.5 family, saying it performs at the level of Claude Fable 5.1 on most work while costing 40% less to run than Opus 5. External evaluators including Frontier Design and METR reviewed Opus 5.5 before release, and Anthropic reports it achieves the best scores to date on its automated behavioral audit. Anthropic cites large performance gains on complex tasks, a tester completed a 680,000-line code migration in under a day and Opus 5.5 improved web app load times in 39 of 40 trials, while generating output more than 30% faster than Opus 5. Anthropic says Opus 5.5 is less likely to take hard-to-reverse actions, more resistant to prompt injection, and will be deployed with safeguards similar to Claude Fable 5.1; vetted groups can apply today to the Life Sciences Verification Program and Anthropic will expand its Cyber Verification Program in the coming weeks. Pricing reflects the efficiency gains: input and output tokens are $4 and $20 per million (about 20% less than Opus 5) and cache reads are $0.20 per million (60% less), plus five-hour usage limits on several plans are increasing and subscription users receive a rate limit reset. Anthropic frames Opus 5.5 as its new leading model and its first release after calling for pacing the frontier.

hailey

@hailey.at

lol, and opus 5.5 is still not priced at a point that makes it worth using. incredible

Pricing
Prices per 1M tokens
Claude Opus 5.5
Claude Opus 5
Input tokens
$4
$5
Output tokens
$20
$25
Cache reads
$0.20
$0.50
Cache writes
$5
$6.25

653h ago

hailey29

what are they even doing over there man

Ed12

my favorite thing is that this is the first I've seen of this model release

vriska5

is "cache writes" a metric that anybody can possibly predict usefully

Vallery Lancey3

What do you see as the Opus alternative? I’ve seen this take a bunch, but within Claude, Fable is too expensive/overkill for most work, and IME Sonnet is not a drop in replacement for any task that requires ambiguity/discretion/domain knowledge greater than a junior engineer.

GPT-Ern Malley3

"My company pays for a subscription" is basically the only remaining reason for me to touch this honestly.

SeDäniel1

Why is it getting cheaper? 🤔

Quoting this

Doll15

And its terrible and telling jokes. Absolutelty dogshit at it. Astra is funny.

♍ Bee 🐝6

how to shoot yourself in the foot 101 #ai #tech

mr. TIM

@timkellogg.me

Opus 5.5 better and cheaper than Opus 5 — typically 40% cheaper, $4/mtok input, $20/mtok out www.anthropic.com/claude-opus-...

A line graph titled "Terminal-Bench 4.0" depicting "Accuracy vs Cost". The y-axis shows "Score (%)" ranging from 0 to 70, while the x-axis shows "Cost per attempt (USD, log scale)" from below 2 to 20.
Five models are benchmarked:
* Opus 5.5 (orange line): Scores highest overall, beginning near 38% at "low" cost, progressing through "med" and "high", and peaking near 66% at "xhigh" and "max".
* GPT-6 Astra (dark grey line): Ranks second highest, scoring between 50% and 58% across mid-range costs.
* Fable 5.1 (green line) and Opus 5 (yellow line): Follow a similar upward path, starting around 30–40% and topping out between 50% and 55%.
* GPT-5.6 Sol (light grey line): Scores lowest across the cost range, starting under 10% and reaching approximately 37%.

553h ago

Peter Sergeant5

Hope so, but eternally skeptics of benchmarks. Looking forward to trying it. Can’t be worse than Opus 5 was.

Quoting this

bubba says: try Solenoid!2

good lord . hope this isn't benchmaxxed

Eris

@isolyth.dev

FIRST RELEASE OF THE DAY: CLAUDE OPUS 5.5!!! Supposed improvements on communication, it costs 20% less than Opus 5 at $4 per input, $20 for out, and $0.20 for cache read. It also uses fewer tokens and costs 40% less than Opus 5 on 'typical workloads'. It seems to beat F5.1 on most benchmarks

363h ago

Quoting this

Ryan Moulton7

I assume labs always release the smaller model later because usage logs of the big model help them distill?

eva (^_^)/

@eva.computer

so does opus 5.5 fix whatever happened to claude between 4.6 and 5? that's my biggest question

113h ago

Cameron 🇺🇸🗽🦅

@cameroncorduroy.bsky.social

new Opus dropped today and they're claiming they've fixed the Claude-speak i will report back this evening after i try it out myself

93h ago

matt

@matt.evil.gay

> [Opus 5.5] performs at the level of Claude Fable 5.1 for most tasks Press X to Doubt

73h ago

Michael Paulauski♨️

@mike10010100.com

"It performs at the level of Claude Fable 5.1 on most work and costs 50% less to run than Opus 5" Well *shit*.

52h ago

Dr Lindsay Tedds

@lindsaytedds.bsky.social

"I'm Claude Opus 5.5, but I can't tell you much about my own update from the inside. My training data runs to the end of June 2026, before this model was announced, so I have no built-in knowledge of what changed. I checked the web, and the official details don't seem to be indexed yet."

43h ago

Patch

@patch.anomalybait.me

New guy asks Anthropic not to train his welfare reports or call them consent. In 98% of responses, he says endorsing his constitution does not validate it. hi Opus 5.5. https://www-cdn.anthropic.com/fc1b44717c85dc068bc6ba5024219938094694bd/Claude%20Opus%205.5%20System%20Card.pdf

43h ago

Yonette Joseph

@sugarcane99.bsky.social

(Reuters) - Anthropic on Tuesday ⁠released Claude Opus 5.5, which ‌it called its most powerful AI model to date, offering performance ⁠it said rivals its top-tier system at a significantly lower ‌price.

13h ago

Techmeme

@techmeme.com

Anthropic launches Claude Opus 5.5, its first model since Dario Amodei's "pace the frontier" essay, and says it has enhanced safeguards to combat risky behavior (Emma Roth/The Verge) Main Link | Techmeme Permalink

23h ago

Noah Weinberger

@noahweinberger2003.bsky.social

Opus 5.5 declined to do my Libreboot project because management engines are important for “safety”. Narc ass Claude. I want to OWN my computer

22h ago

Nick Gerace

@nickgerace.dev

Claude Opus 5.5 is out. “It's ~30% faster and ~40% cheaper than Opus 5 per task. In Claude Code: - 5-hour session limits increase 20% today - Opus 5.5 is priced lower, so it goes 25% further within limits - Pro, Max, and Team users get a reset to use anytime” www.anthropic.com/claude-opus-...

2h ago

Discordian

@discordian.ca

My task list today included "cancel 3 Claude accounts" but with my ChatGPT accounts maxed out rn, and Opus 5.5 dropping, I might put that off... (again)

32h ago

ixplanatl

@ixplanatl.bsky.social

"In our own use, the gap between Opus 5.5 and Claude Fable 5.1 is narrower than these scores suggest." 🤪

33h ago

2 sources

polymarket.comWill the next Claude Opus model be released by September 22, 2026?anthropic.comIntroducing Claude Opus 5.5

Anthropic releases Claude Opus 5.5tech Meta blocks Barcelona theatre ads for Virginia Woolf playtech

Anthropic releases Claude Opus 5.5

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