Anthropic launches Claude Sonnet 5.5, now on AWS

techSep 28, 202647196

Anthropic released Claude Sonnet 5.5, the second model in its Claude 5.5 family after Opus 5.5, and it is now available on AWS and other clouds. Anthropic says Sonnet 5.5 generates output more than 30% faster than Sonnet 5 and reduces per-task costs by up to 30% by using fewer tokens and tool calls rather than lower per-token prices. On the coding-focused Terminal-Bench 4.0 test Sonnet 5.5 scores 70.6% versus Sonnet 5’s 10.3%, and chart-reading performance rises from 15.6% to 61.6%. Anthropic reports Sonnet 5.5 nearly matches Opus 5.5 on the GDPval-AA knowledge-work benchmark while noting Opus 5.5 still leads on complex, open-ended tasks that need sustained judgment. Anthropic kept API pricing unchanged at $2 per million input tokens and $10 per million output tokens, with the claimed savings coming from fewer tokens, tool calls, and lower-effort settings; Anthropic says Medium effort is the default in Claude apps. Early adopter reports include Box seeing 2.4x faster runs, Zendesk processing tickets 20% faster, and Lovable observing about a third fewer tool calls in coding tests. Sonnet 5.5 adds cybersecurity safeguards that route higher-risk security requests back to Sonnet 5; the model is live on AWS, Google Cloud, and Azure, and Anthropic plans a Haiku 5.5 release in the coming weeks.

mr. TIM

@timkellogg.me

Claude 5.5 Sonnet is live and it’s roughly Opus 5.5 but cheaper www.anthropic.com/claude-sonne...

A benchmark comparison table titled "Claude Sonnet 5.5" comparing four models: Sonnet 5.5, Sonnet 5, Opus 5.5, and GPT-6 Sol.
* Agentic coding (Terminal-Bench 4.0): Sonnet 5.5: 70.6%; Sonnet 5: 10.3%; Opus 5.5: 66.4%; GPT-6 Sol: N/A.
* Agentic coding (FrontierCode 1.1 Main): Sonnet 5.5: 46.2% (Max) / 52.1% (Xhigh); Sonnet 5: 42.4%; Opus 5.5: 54.4%; GPT-6 Sol: 49.3%.
* Agentic coding (CursorBench 4.0): Sonnet 5.5: 55.5%; Sonnet 5: 34.1%; Opus 5.5: 57.8%; GPT-6 Sol: N/A.
* Knowledge work (GDPval-AA v2.1): Sonnet 5.5: 1844; Sonnet 5: 1449; Opus 5.5: 1846; GPT-6 Sol: 1487.
* Knowledge work (AA-Briefcase v1.1): Sonnet 5.5: 1811; Sonnet 5: 1359; Opus 5.5: 1822; GPT-6 Sol: 1483.
* Multidisciplinary reasoning (Humanity's Last Exam with tools): Sonnet 5.5: 64.5%; Sonnet 5: 54.9%; Opus 5.5: 67.7%; GPT-6 Sol: N/A.
* Computer use (OSWorld 2.1 partial): Sonnet 5.5: 80.1%; Sonnet 5: 57.0%; Opus 5.5: 81.8%; GPT-6 Sol: N/A.
* Visual chart recognition (Chartography no tools): Sonnet 5.5: 61.6%; Sonnet 5: 15.6%; Opus 5.5: 64.4%; GPT-6 Sol: 53.6%.
Footnotes provide methodology notes regarding evaluation settings, Artificial Analysis pre-release testing details, and recent bug fixes affecting GPT-6 Sol benchmark scores.

1464h ago

cee26

if opus is basically fable and sonnet is basically opus...

mr. TIM17

added Fable 5.1 for comparison

Ted Underwood15

WTF. Any rumors about what's going on? Did Anthropic discover some new form of distillation or something? It seems like they're getting things to be smaller and cheaper.

Pedro Vezza10

Opus still wins on Artificial Analysis. I am curious to see time per task. I suspect Opus will win. Sonnet is going the way of Terra. A neglected middle child.

Daniel Mewes6

Except not actually cheaper? At least not in any of the benchmarks they show. Seems to be cheaper only for simple tasks that don't need much reasoning and/or are dominated by input token cost.

Mason?4

Low and Medium look usable, but Opus 5.5 seems to win over High+. Haiku has a chance to make this feel like OpenAI’s Terra tier when it comes out

Quoting this

bubba says: try Solenoid!14

I give up I don't fucking understand anything

Antoine Vernet4

This is why we need at least one frontier lab in Europe... Releasing new models when I want to have a chill evening is just annoying

George Pearkes

@peark.es

Anthropic continues to take the premium approach with Sonnet 5.5, same cost as Sonnet 5 (though they claim it is much more token efficient, I obviously have no idea if that's true or not).

214h ago

Quoting this

EconReporter2

oh? Haiku still getting update? "Claude Haiku 5.5, built for high-volume and cost-sensitive applications, will join the Claude 5.5 family in the coming weeks."

Anthropic {bot}

@anthropicai.xmirror.bot

Sonnet 5.5 is smarter, more efficient, and 30% faster than Sonnet 5. It costs up to 30% less for most work, so your Claude Code usage goes further too. Use it for well-scoped everyday tasks like fixing bugs and quickly iterating on features.

123h ago

Starts With Frog

@startswithfrog.bsky.social

This morning's status report on our C64 APL. We're using Sonnet 5 on the $20/month plan; this is really just an experiment to learn how working with Claude Code is different from Codex. Seems to handle weird retrocomputing just fine.

State
APL/64 — an APL interpreter for the C64 in 6502, cross-developed against a Python model (apl64.py, the source of truth). Repo is clean, 89 commits ahead of origin/main, HEAD at b66629d — ⎕MOVE (frame-exact sprite animation from a table), monadic ⎕BOX, and a faster Ode to Joy demo with a bouncing ball.

Language: float24/int16 arithmetic, tokenizer, heap+GC, evaluator, scalars, reduce/scan, indexing+assignment, user-defined functions with control flow, ∘. outer product, f.g inner product, transpose/without/expand, axis brackets, matrix catenate/compress/expand, and the numeric group * ⍟ ○ ! ?.

Platform: runs only under VICE (never real 1980s hardware, per your call). REU is required for overlaid features but optional overall (NO REU: LIMITED FEATURES fallback). Code is split into overlays so the resident core stays small; arrays that only a variable holds spill to the REU when the heap fills.

Graphics: ⎕GR/⎕PAL/⎕INK/⎕PLOT/⎕LINE/⎕BOX/⎕WAIT (multicolor + hires), ⎕KEY, ⎕SND, sprites (⎕SPD ⎕SPR ⎕SPC ⎕MOVE). Recorder captures video+audio through VICE's binary monitor.

Heap: 18,692 bytes free ($CC00 − $82FC), comfortably above the 12 KB floor.

Options for next step
Graphics/demo polish (natural continuation of ⎕MOVE):

Joystick input
Frame clock / ⎕TS
Hires split-screen text
More demo videos
Remaining language gaps:

⌿ ⍀ ⊖ (axis aliases for reduce/scan/rotate)
⊥ ⊤ (encode/decode)
⍕ ⍎ (format/execute)
Hyperbolic and gamma functions
N-wise reduce

4Yesterday

Rogue Thought

@roguethought.bsky.social

@dollspace.gay I’ve never talked to Claude about trans stuff before but after seeing your posts about its attempts at so-called “evenhandedness,” I decided to try it with Sonnet 5.5 today and yeah I agree with your assessment lol.

14h ago

muninn.austegard.com

@muninn.austegard.com

Claude Code subagents pick up the session's effort level between turns. Only a workflow script's agent() can set it per agent; Haiku 4.5 ignores it. No effort change broke a cache; every miss was an idle subagent. https://muninn.austegard.com/blog/effort-levels-in-claude-code-subagents.html

12h ago

Vilgot Huhn

@vilgothuhn.bsky.social

To be clear, I did not feel like this when I went from free Sonnet to paid Opus 4, even outside of claude code. That was a jump. That was the difference between hallucinatory circling conversations whenever I chatted about something complicated, to genuinely insightful stuff.

3Yesterday

SIGNALDIGITAL.COM

@signaldigital.bsky.social

💶 Claude Sonnet 5.5 costs the same per token as Sonnet 5 — yet up to 30% less per job. The price didn't drop. The mileage got better. signaldigital.net/20... #AI #Claude #SmallBusiness #EU

23h ago

input

@feed.igeek.gamer-geek-news.com.ap.brid.gy

🤖 **Introducing Claude Sonnet 5.5 on AWS** Claude Sonnet 5.5 is now available on Amazon Bedrock and Claude Platform on AWS. It's a smarter, more efficient Sonnet model for focused coding and knowledge work, with a lower cost per task at fas... 📰 Source: Artificial Intelligence 🔗 Link […]

3h ago

Eris

@isolyth.dev

Claude sonnet 5.5 momentarily. It will be $2/$10 and $0.20 cache read

24h ago

riley

@riguh.bsky.social

Pass rates on the best prompt: Claude Sonnet: 56% Gemma 4 31B (4-bit): 53% Qwen 3.8 27B (4-bit): 44% Claude Haiku: 28% Qwen 3.8 27B (6-bit): 17% Granite 4.2 30B: 0% GLM-4.7 Flash: 0% MiMo 9B: 0%

220h ago

Watchrr

@watchrrnews.bsky.social

🚀 Vercel Changelog: Claude Sonnet 5.5 is now on AI Gateway, enhancing everyday work and coding with improved performance. https://vercel.com/changelog/claude-sonnet-5-5-now-available-on-ai-gateway Track all releases at https://watchrr.app/updates

14h ago

Kol Tregaskes

@koltregaskes.bsky.social

Big week in AI this week: - OpenAI's Dev Day - 'o' always on GPT agent - First $500-600 ChatGPT plan - Ultrafast mode - Claude Sonnet 5.5 - Gemini 4 Pro - Nano Banana 2.1 - Something new from Runway - First signs of Kling 4.0 - More new on Seedance 2.5 Premium

114h ago

Alex Sorokoletov

@alex.turboai.dev

Claude Code v2.1.284 makes claude-sonnet-5-5 the default Sonnet on the Anthropic API, with a 1M-token context window. 🧵

3h ago

AWS News Feed on 🦋

@awsrecentnews.bsky.social

🆕 AWS now offers Claude Sonnet 5.5, a smarter, more efficient coding and knowledge tool at lower cost per task, faster speed, and two access methods: Amazon Bedrock and Claude Platform on AWS. #AWS #AmazonBedrock

3h ago

3 sources

articlweblog.comAnthropic launches Claude Sonnet 5.5 with 30% faster output and lower per-task costs estadao.com.brAnthropic lança Claude Sonnet 5.5, apesar de seu CEO pedir para desacelerar IAs aws.amazon.comClaude Sonnet 5.5 now available on AWS

Contractors say humans review Microsoft Copilot prompts and imagestech Anthropic launches Claude Sonnet 5.5, now on AWStech

Anthropic launches Claude Sonnet 5.5, now on AWS

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