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Claude Opus 4.5: Anthropic's Most Capable Model in the Claude 4.5 Family

Claude Opus 4.5 is Anthropic's advanced large language model, released on November 25, 2025, as the flagship in their Claude 4.5 family. It sits above Claude Sonnet 4.5 and Haiku 4.5 in raw intelligence and depth of reasoning.

Claude Opus 4.5 uses a large context window (on the order of hundreds of thousands of tokens) and long outputs, so it can work across big codebases, long documents, or multi-step plans in one session.

What Claude Opus 4.5 Excels At

Claude Opus 4.5’s key capabilities break down into three big buckets: advanced software engineering, strong agentic behavior, and high-end office/knowledge work.

Software Engineering in Depth

Claude Opus 4.5 represents a significant leap forward in AI-assisted software development.

• Long-horizon coding: Claude Opus 4.5 can understand and modify large, multi-file codebases, plan a multi-step refactor, update tests, and iterate until CI passes, rather than just editing a single snippet.​
• Higher benchmark performance: On internal coding benchmarks (including SWE-bench Verified and Terminal Bench–style tasks), it fixes more real bugs and completes more tasks while using significantly fewer tokens than Sonnet 4.5, making it viable as a primary coding engine.​
• Practical workflows: Possible use cases of Claude Opus 4.5 include cross-repo refactors, framework or language migrations, large code reviews that focus on real issues instead of noise, and acting as the “lead” model behind tools like Claude Code, Cursor, or GitHub Copilot-style experiences.​

Agentic and Tool-Using Behavior

Claude Opus 4.5 is also built to sustain complex, goal-directed agentic work over extended periods.

• Multi-step planning: Claude Opus 4.5 is optimized for long-running “agent” workflows where the model decomposes a goal into steps, makes a plan file, and executes it while updating progress, instead of jumping straight to an answer.​
• Tool and sub-agent orchestration: Opus 4.5 can coordinate a team of sub-agents (e.g., one reading docs, one editing files, one running tests) and use advanced tool features like programmatic tool calling, tool search, and memory to keep state over hours-long tasks.​
• Better autonomy: In internal evals on deep research and complex enterprise tasks, it maintains direction for long periods, avoids dead ends more often than earlier models, and can use browsing, code execution, and computer-use tools together to complete workflows with minimal supervision.​

Office Works and Analysis

Claude Opus 4.5 brings AI capability to the everyday tools that drive business operations—spreadsheets, presentations, documents, and desktop applications.

• Spreadsheet and modeling strength: Claude Opus 4.5 offers more accuracy and efficiency in Excel and financial modeling evaluations, making it suited to building multi-sheet models, checking formulas, and automating complex spreadsheet tasks.​
• Slides, docs, and long content: It handles 10–15 page documents (reports, chapters, specs) with good structural consistency and can keep a long conversation going by summarizing and compacting its own context as needed.​
• Computer use upgrades: With improved “computer use” and a zoom action for screen regions, it can reliably read fine UI text, operate across browser tabs, and drive desktop automation apps (e.g., Claude for Chrome, Claude for Excel), which is what powers the “use my computer” style workflows.​

What's New of Claude Opus 4.5 Compared to Claude Opus 4.1

Claude Opus 4.5 offers better reasoning and coding quality than previous Opus versions, especially on long-horizon tasks where it must keep track of many moving parts. It's more efficient and often solves problems with fewer tokens, which makes it cheaper to run in practice at similar or better quality.

Claude Opus 4.5 also supports an “effort” control: you (or an app) can adjust how hard it “thinks” (low/medium/high) to trade off speed/cost against depth of reasoning.

Specs & Benchmark Comparison

Aspect	Claude Opus 4.5	Gemini 3 Pro	GPT-5.1	Claude Sonnet 4.5	Claude Haiku 4.5
Release Date	November 24, 2025	November 18, 2025	November 12, 2025	September 2025	October 2025
Context Window	200,000 tokens	1,000,000 tokens	400,000 tokens	200,000 tokens	200,000 tokens
Key Strengths	Coding, agents, computer use; outperforms on complex workflows and enterprise tasks	Multimodal reasoning, agentic coding, visual context; excels in broad problem-solving	Conversational AI, adaptive reasoning, efficiency; strong in math/coding with tool integration	Coding and agentic workflows; balanced for mid-tier tasks	Fast, cost-efficient assistance; good for high-volume, simple queries
SWE-bench Verified (Coding Accuracy)	80.9%	76.2%	77.9% (Codex-Max variant: 76.3%)	77.2%	-
Pricing (Input/Output per M Tokens)	$5 / $25	$2 / $12 ($4 / $18 for >200K tokens)	$1.25 / $10	$3 / $15	$1 / $5
Access	Claude API, apps, cloud platforms; Max/Team/Enterprise tiers	Gemini app, AI Studio, Vertex AI; Pro/Ultra plans	ChatGPT, API; Plus/Pro tiers	Same as Opus	Same as Opus

Best Ways to Access Claude Opus 4.5

You can use Claude Opus 4.5 either through the official Claude website and upgrade to a paid tier. Or you can access it through coding tools like Claude Code/Cursor or via developer APIs.

But sometimes the official access may come with restrictions. And you may not be able to use it smoothly all the time. If you want a beginner-friendly, restriction-free way to get access to Claude Opus 4.5, we suggest you try HIX AI!

HIX AI is an all-in-one AI agent platform coming with all the cutting-edge language models. We offer easy and stable access to these advanced models for everyone, including Claude Opus 4.5, Claude Sonnet 4.5, Haiku 4.5, Gemini 3 Pro, GPT-5.1 and more.