Claude Opus

weights

closed

data

closed

code

closed

license

Proprietary(API/Bedrock/Vertex/claude.ai)

Anthropic distributes no weights for Opus in any form, serving it only through the API, Bedrock, Vertex and claude.ai. That holds across the whole Opus 4.x line, so it is closed on every dimension regardless of which point release is read.

• https://www.anthropic.com/claude-opus-5-5 recorded 2026-09-29

  Latest Opus release: "Claude Opus 5.5 is now available on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure." Searched the body for weights, self-host, on-prem and license: none.

• https://www.anthropic.com/news/claude-4 recorded 2026-09-29

  Launch post for the Opus 4 line: "Both models are available on our API, Amazon Bedrock, and Google Cloud's Vertex AI." Searched the body for weights, self-host, on-prem and license: none.

• https://www.anthropic.com/news/claude-opus-4-8 recorded 2026-09-29

  Anthropic sells Opus 4.8 as metered API access: "Claude Opus 4.8 is available everywhere today. Pricing for regular usage is unchanged from Opus 4.7: $5 per million input tokens and $25 per million output tokens". Searched the body for weights, open source, license, self-host and on-prem: none.

Opus is Anthropic's premium tier. Its launch post carries enterprise testimonials from partners such as Replit and Vercel but no per-model usage or user figure, so this reading is directional rather than measured.

• https://openrouter.ai/rankings recorded 2026-08-13

  "Live LLM rankings based on benchmarks and real data from millions of people using models through OpenRouter" - the leaderboard itself is client-rendered, so a plain fetch shows the page exists but not which models rank where

• https://www.anthropic.com/news/claude-opus-4-7 recorded 2026-08-13

  named enterprise testimonials (Cursor's Michael Truell on CursorBench, Harvey on BigLaw Bench, Replit's Michele Catasta); no quantitative per-model usage or user figure anywhere on the page

This score reads Claude Opus 5.5, the tier's current and strongest release. It leads the Artificial Analysis index, ahead of Anthropic's own Sonnet and Fable models and of OpenAI's and Google's flagships, and Anthropic calls it its new leading model. The Opus 4.x releases sit well below it on the same index.

• https://artificialanalysis.ai/leaderboards/models recorded 2026-10-08

  The leaderboard's embedded model records, ranked by intelligenceIndex, put Claude Opus 5.5 (Max) first at 57.62, then Claude Sonnet 5.5 (Max) 56.0, Claude Fable 5.1 (Max) 53.35, GPT-6 Astra (Max) 52.67, Gemini 4 Argon (High) 52.56, GPT-6.1 Sol (Max) 51.83 and Muse Spark 1.3 (Max) 48.09 among models not marked deprecated; Grok 4.7 (Xhigh) follows at 46.45, Gemini 3.8 Flash (High) at 40.93, K2 Horizon 375B A23B at 30.5 and Gemini 3.1 Pro Preview at 29.72. The digest drifts between fetches because the page carries live pricing and throughput figures.

• https://artificialanalysis.ai/models/claude-opus-5-5 recorded 2026-10-08

  "scores 58 on the Artificial Analysis Intelligence Index, placing it well above average among comparable models (median: 26)"; Intelligence rank "# 1 / 225"; no deprecation banner.

• https://platform.claude.com/docs/en/models/overview recorded 2026-10-08

  Models overview lists "Claude Fable 5.1 Claude Opus 5.5 Claude Sonnet 5.5 Claude Haiku 5.5" as current, and says "start with Claude Opus 5.5 for most workloads. Use Claude Fable 5.1 for demanding reasoning and long-horizon agentic work".

• https://www.anthropic.com/claude-opus-5-5 recorded 2026-10-08

  Anthropic's Opus 5.5 page: "Opus 5.5 is a major step up from Opus 5. It's the new leading model" and "On our benchmarks, Claude Opus 5.5 leads in agentic coding, computer use, and knowledge work." Vendor-reported.