Anthropic
anthropic.com › news › claude-opus-4-5
Introducing Claude Opus 4.5
November 24, 2025 - 4: A fetch-enabled version of BrowseComp-Plus. Specifically, the improvement was from 70.48% without using the combination of techniques to 85.30% using it. ... All evals were run with a 64K thinking budget, interleaved scratchpads, 200K context window, default effort ...
Claude Docs
platform.claude.com › docs › en › about-claude › models › whats-new-claude-4-5
What's new in Claude 4.5 - Claude Docs
1 month ago - Claude Haiku 4.5: Our fastest and most intelligent Haiku model with near-frontier performance. Available with a 200k token context window. Claude Opus 4.5 represents our most intelligent model, combining maximum capability with practical performance.
Is Claude Code Sonnet 4.5 With 1M Context Actually Better Than 200k?
I clear context around 200k-250k. Performance degrades too much after that. More on reddit.com
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November 20, 2025Context Length limits finally SOLVED!
People on this sub have reported that when it compresses it, you lose a lot of performance and context from the compressed data... I wouldn't celebrate just yet. More on reddit.com
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1 month agoThe context window simply needs to be larger with Opus as the default
Opus 4.5 does not use tokens faster. In fact in many cases, Anthropic tests showed Opus uses fewer tokens (because it gets to the right answer more directly). Set to a medium effort level, Opus 4.5 matches Sonnet 4.5’s best score on SWE-bench Verified, but uses 76% fewer output tokens. At its highest effort level, Opus 4.5 exceeds Sonnet 4.5 performance by 4.3 percentage points—while using 48% fewer tokens. And since Opus 4.5 is also less expensive per token than Opus 4.1, this means it often costs the same or less in $$ when paying for raw tokens for Opus 4.5 than for Sonnet 4.5. That is why their raised the usage limits. The old limits were to stop people from using a very expensive and not more efficient model. The new model is more efficient and more effective and doesn't cost them more on average. More on reddit.com
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1 month agoHas anyone noticed how Sonnet 4.5 context window is smaller in desktop app?
Check the stats with /context and see exactly it is using. More on reddit.com
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October 4, 2025Videos
14:27
Claude Code just had a MAJOR update. Here's how to use it. - YouTube
07:26
Claude Opus 4.5: The only model you need - YouTube
24:45
The only Claude Code guide you'll ever need (Opus 4.5) - YouTube
09:13
Claude Code: 1 Million Tokens + Unlimited Agents Changes Everything ...
31:28
Make Claude Code 100x BETTER (Context Engineering) - YouTube
Reddit
reddit.com › r/claudecode › the context window simply needs to be larger with opus as the default
r/ClaudeCode on Reddit: The context window simply needs to be larger with Opus as the default
1 month ago -
I'm on the 20x Max plan. I get that Opus will use tokens faster, and Anthropic acknowledged this by increasing the total token usage to be something equivalent to the same amount of usage you'd get with Haiku (whether or not that is really true remains to be seen). However, they didn't raise the context window token limit of 200k (I don't have access to the 1M limit).
I just used my first prompt (which was a pretty standard one for me) to help find an issue that threw an error on my front-end, and after its response (which wasn't that helpful), I'm already down to 9% context remaining before auto-compacting.
If Anthropic is going to acknowledge that token consumption will be higher with Opus and scale some of the limits up accordingly, they really should increase the context limit as well.
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Opus 4.5 does not use tokens faster. In fact in many cases, Anthropic tests showed Opus uses fewer tokens (because it gets to the right answer more directly). Set to a medium effort level, Opus 4.5 matches Sonnet 4.5’s best score on SWE-bench Verified, but uses 76% fewer output tokens. At its highest effort level, Opus 4.5 exceeds Sonnet 4.5 performance by 4.3 percentage points—while using 48% fewer tokens. And since Opus 4.5 is also less expensive per token than Opus 4.1, this means it often costs the same or less in $$ when paying for raw tokens for Opus 4.5 than for Sonnet 4.5. That is why their raised the usage limits. The old limits were to stop people from using a very expensive and not more efficient model. The new model is more efficient and more effective and doesn't cost them more on average.
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Preserve the main context for actual useful work - Use sub agents, the main should basically be the orchestration and leave all the 'grunt work' to subs.
Substack
simonw.substack.com › p › claude-opus-45-and-why-evaluating
Claude Opus 4.5, and why evaluating new LLMs is increasingly difficult
1 month ago - The model supports enhanced computer use, specifically a zoom tool which you can provide to Opus 4.5 to allow it to request a zoomed in region of the screen to inspect. “Thinking blocks from previous assistant turns are preserved in model context by default“ - apparently previous Anthropic models discarded those. I had access to a preview of Anthropic’s new model over the weekend. I spent a bunch of time with it in Claude Code, resulting in a new alpha release of sqlite-utils that included several large-scale refactorings - Opus 4.5 was responsible for most of the work across 20 commits, 39 files changed, 2,022 additions and 1,173 deletions in a two day period.
Anthropic
anthropic.com › claude › opus
Claude Opus 4.5
Hybrid reasoning model that pushes the frontier for coding and AI agents, featuring a 200K context window ... Claude Opus 4.5 is our most intelligent model to date. It sets a new standard across coding, agents, computer use, and enterprise workflows.
Data Studios
datastudios.org › post › claude-opus-4-5-vs-claude-sonnet-4-5-model-differences-pricing-structure-context-windows-and-mor
Claude Opus 4.5 vs Claude Sonnet 4.5: Model Differences, Pricing Structure, Context Windows, and more
1 month ago - Opus 4.5 focuses on higher reasoning quality within its large context rather than maximum window expansion, prioritizing structured logic, better dependencies across segments and superior performance under cognitive load.
Microsoft Azure
azure.microsoft.com › blog home › ai + machine learning › introducing claude opus 4.5 in microsoft foundry
Introducing Claude Opus 4.5 in Microsoft Foundry | Microsoft Azure Blog
1 month ago - Opus 4.5 is also one of the strongest tool-using models available today, capable of powering agents that work seamlessly across hundreds of tools. Developers gain access to several important upgrades: Programmatic Tool Calling: Execute tools directly in Python for more efficient, deterministic workflows. Tool Search: Dynamically discover tools from large libraries without using up space in the context window.
Milvus
blog.milvus.io › ai-quick-reference › whats-the-recommended-context-window-size-for-claude-opus-45-production-workloads
What’s the recommended context window size for Claude Opus 4.5 production workloads?
Claude Opus 4.5 supports a 200K-token context window, but for production workloads developers are encouraged to use smal
Medium
medium.com › @leucopsis › claude-opus-4-5-review-1d9b46bb053a
Claude Opus 4.5 - First Look. When Anthropic released Claude Opus 4.5… | by Barnacle Goose | Nov, 2025 | Medium
3 weeks ago - Earlier parts of a conversation or project are summarised and re-encoded so that logically important constraints are preserved even when the raw text has been pushed far into the past. But I think the base Opus 4.5 context window remained the same as before i.e. 200K. In API one can use the new memory tool that enables Claude to store and retrieve information outside the context window.
Reddit
reddit.com › r/claudecode › is claude code sonnet 4.5 with 1m context actually better than 200k?
Is Claude Code Sonnet 4.5 With 1M Context Actually Better Than 200k? : r/ClaudeCode
November 20, 2025 - The general consensus at my work, of those who use Roo with Claude 4.5 under the hood, is to keep the context window at 200 ... Its useful for long running complex prompts such as debugging an issue where short ones will just lead to it going around in circles.
Reddit
reddit.com › r/claudeai › context length limits finally solved!
r/ClaudeAI on Reddit: Context Length limits finally SOLVED!
1 month ago -
With the introduction of Opus 4.5, Anthropic just updated the Claude Apps (Web, Desktop, Mobile):
For Claude app users, long conversations no longer hit a wall—Claude automatically summarizes earlier context as needed, so you can keep the chat going.
This is so amazing and was my only gripe I had with Claude (besides limits), and why I kept using ChatGPT (for the rolling context window).
Anyone as happy as I am?
Skywork
skywork.ai › home › claude 4.5 context length: how extended memory improves conversations
Claude 4.5 Context Length & Extended Memory Explained
September 30, 2025 - Extended memory is the notebook ... of 2025‑09‑30, Anthropic states that Claude Sonnet 4 and 4.5 can support very large windows in developer environments....
LessWrong
lesswrong.com › posts › HtdrtF5kcpLtWe5dW › claude-opus-4-5-is-the-best-model-available
Claude Opus 4.5 Is The Best Model Available
3 weeks ago - Michael Trazzi: Claude Opus 4.5 feels alive in a way no model has before. We don’t need superintelligence to make progress on alignment, medicine, or anything else humanity cares about. This race needs to stop. The ability to have longer conversations is to many a big practical upgrade. Knud Berthelsen: Clearly better model, but the fact that Claude no longer ends conversations after filling the context window on its own has been a more important improvement.
PromptLayer
blog.promptlayer.com › opus-4-5-what-we-expect
Opus 4.5: What We Expect
October 23, 2025 - Opus 4.1 arrived in August 2025, introducing extended thinking modes and a massive 200,000-token context window. Then came Sonnet 4.5 in late September, and this is where things got interesting.
Google Cloud
cloud.google.com › blog › products › ai-machine-learning › claude-opus-4-5-on-vertex-ai
Claude Opus 4.5 on Vertex AI | Google Cloud Blog
1 month ago - Improve performance and reduce ... with flexible Time To Live (TTL) up to one hour, efficient batch predictions, a 1M token context window for Claude Sonnet 4.5 (in beta), and web search (preview)....
OpenRouter
openrouter.ai › anthropic › claude-opus-4.5
Claude Opus 4.5 - API, Providers, Stats | OpenRouter
November 24, 2025 - Opus 4.5 supports advanced tool use, extended context management, and coordinated multi-agent setups, making it well-suited for autonomous research, debugging, multi-step planning, and spreadsheet/browser manipulation.
ClaudeLog
claudelog.com › home › faqs › what is context window
What is Context Window in Claude Code | ClaudeLog
November 11, 2025 - The context window is Claude's memory capacity for a single conversation. It includes your messages, Claude's responses, file contents, and tool outputs. Most Claude models have a 200K token context window, but Claude Sonnet 4.5 via API offers ...
Cline
cline.bot › blog › anthropics-claude-opus-4-5-is-live-in-cline
Anthropic's Claude Opus 4.5 is Live in Cline - Cline Blog
1 month ago - Claude Opus 4.5 is now available through the Cline provider. It's highly performant on benchmarks: 80.9% SWE-bench Verified, 59.3% on Terminal-bench 2.0. Up to 65% fewer tokens than previous models on comparable tasks. Pricing is $5/$25 per million tokens with a 200K context window.
Amazon Web Services
aws.amazon.com › generative ai › amazon bedrock › anthropic
Claude by Anthropic - Models in Amazon Bedrock – AWS
1 week ago - By default, Anthropic's Claude models have a 200,000 token context window enabling you to relay a large volume of information to Claude. This translates to roughly 150,000 words, or over 500 pages of material. Sonnet 4 and 4.5 now offers an expanded context length of 1 million tokens (preview).
Artificial Analysis
artificialanalysis.ai › articles › claude-opus-4-5-benchmarks-and-analysis
Claude Opus 4.5 Benchmarks and Analysis
1 month ago - Claude Opus 4.5 (Thinking) scores 5% on CritPt, a frontier physics eval reflective of research assistant capabilities. It sits only behind Gemini 3 Pro (9%) and ties GPT-5.1 (high, 5%) 📈 Largest increases in coding and agentic tasks: Compared to Claude Sonnet 4.5 (Thinking), the biggest uplifts appear across coding, agentic tasks, and long-context reasoning, including LiveCodeBench (+16 p.p.), Terminal-Bench Hard (+11 p.p.), 𝜏²-Bench Telecom (+12 p.p.), AA-LCR (+8 p.p.), and Humanity's Last Exam (+11 p.p.).