Technology & AI
Fedor Zhilkin
Dec 19, 2025
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Updated on
Dec 19, 2025
On November 24, 2025, Anthropic released Claude Opus 4.5—the most powerful model in the Claude lineup to date. According to developers, this is the world's best model for programming, creating autonomous agents and computer control.
Model price decreased 66% compared to previous version, while performance significantly increased. Opus 4.5 uses fewer tokens to achieve the same results, making it more economical for large-scale projects.
What Is Claude Opus 4.5
Claude Opus 4.5 is a large language model from Anthropic, specifically optimized for working with complex programming tasks, data analysis and long-term projects.
Main difference from predecessors—ability to understand task context without additional explanations. Anthropic's internal testers noted that the model "just understands," handling tasks that were nearly impossible for Sonnet 4.5 literally weeks ago. When a model is pointed to a complex bug in a multi-component system, Opus 4.5 finds a solution itself.
Model available through Anthropic API (identifier claude-opus-4-5-20251101), claude.ai web application, iOS and Android mobile apps, and through cloud platforms Amazon Bedrock, Google Vertex AI and Azure. Context window is 200,000 tokens, maximum output up to 64,000 tokens, knowledge base current through March 2025.
Main Opus 4.5 Achievements
The result of 80.9% on the SWE-bench Verified test is the best score among all existing models. This test checks the ability to solve real software development tasks, including fixing bugs in open GitHub projects. For comparison: GPT-5.1 Codex Max showed 77.9%, Gemini 3 Pro—76.2%, and Claude Sonnet 4.5—77.2%.
On the SWE-bench Multilingual test, the model leads in seven of eight programming languages. This speaks to its universality—works equally well with Python, JavaScript, Java, C++ and other languages.
Anthropic also conducted internal tests where models solved difficult exams for candidates for performance engineer positions. Within the two-hour limit, Opus 4.5 scored higher than any human in the entire history of this exam.
Effort Parameter — Unique Feature
Unique feature of Claude Opus 4.5—new effort parameter in API that allows controlling how much computational resources a model spends thinking about a task. The parameter has three values: low, medium and high. High level set by default—maximum reasoning depth.
When set to medium level, Opus 4.5 achieves the same result as Sonnet 4.5 at maximum but uses 76% fewer output tokens. At a high level, the model surpasses Sonnet 4.5 by 4.3 percentage points while using 48% fewer tokens.
This means developers can choose between speed and quality depending on the task. For simple questions can use low level, for complex programming tasks—high.
Security and Protection
Anthropic claims Claude Opus 4.5 is the safest and most aligned model among all modern large language models. The company significantly improved protection against prompt injection—attacks where malicious actors try to inject harmful instructions into normal queries.
In tests developed by Gray Swan company, Opus 4.5 showed best resistance to such attacks among all models in industry. The test included only very difficult attacks capable of fooling most existing models.
The model also shows a minimal level of unwanted behavior by the behavior metric. This metric measures a wide spectrum of problematic behavior—from cooperating with malicious actors to unwanted actions the model initiates itself.
Comparison with Competitors
The large language model market in late 2025 sees fierce competition. In November-December, several flagship models were released at once: Claude Opus 4.5 from Anthropic, GPT-5.2 and GPT-5.1 from OpenAI, and Gemini 3 Pro from Google. Each company claims breakthrough results, but actual metrics differ.
Key comparison parameters—performance on standard tests (especially SWE-bench for programming), usage price, context window size and additional capabilities like working with images or computer control. Speed and availability through various platforms are also important.
Feature | Claude Opus 4.5 | Claude Sonnet 4.5 | GPT-5.2 | GPT-5.1 Codex Max | Gemini 3 Pro |
Release date | Nov 24, 2025 | Sep 29, 2025 | Dec 12, 2025 | Nov 2025 | Nov 2025 |
Developer | Anthropic | Anthropic | OpenAI | OpenAI | Google DeepMind |
Context | 200K tokens | 200K / 1 M (beta) | 128K tokens | ~200K tokens | 2M tokens |
Max output | 64K tokens | 64K tokens | 64K tokens | ~16K tokens | 64K tokens |
Price in/out | $5 / $25 per 1M | $3 / $15 per 1M | $2 / $10 per 1M | $1.25 / $10 per 1M | $2 / $12 per 1M |
SWE-bench Verified | 80.9% 🥇 | 77.2% | ~78% | 77.9% | 76.2% |
Programming | Best | Excellent | Excellent | Excellent | Excellent |
Computer use | Excellent | Excellent | Average | Good | Good |
Agents | Best | Excellent | Good | Good | Good |
Mathematics | Excellent | Excellent | Excellent | Excellent | Excellent |
Multimodal | Text + images | Text + images | Text + images + audio | Text + images + audio | Text + images + video |
Speed | Medium | Fast | Fast | Medium | Fast |
Effort parameter | ✅ Yes | ❌ No | ❌ No | ❌ No | ❌ No |
Extended thinking | ✅ Yes | ✅ Yes | ✅ Yes (o1) | ✅ Yes (o1) | ❌ No |
Memory | ✅ Beta | ✅ Beta | ✅ Yes | ✅ Yes | ❌ No |
Attack protection | Best | Excellent | Good | Good | Good |
IDE integration | GitHub Copilot, Cursor | GitHub Copilot, Cursor | GitHub Copilot, Cursor | GitHub Copilot | Android Studio |
Comparison Conclusions:
Claude Opus 4.5 shows best programming results (80.9% on SWE-bench) and offers a unique effort parameter for work quality control. This is the only model where you can choose reasoning depth, critical for cost optimization on large projects. However, it's more expensive than most competitors—$5/$25 vs $2/$10 for GPT-5.2 and $2/$12 for Gemini 3 Pro.
Pricing and Usage
Claude Opus 4.5 usage cost through API is $5 per million input tokens and $25 per million output tokens. This is 66% cheaper than previous version Opus 4.1, which cost $15 and $75 respectively.
Additional savings available through prompt caching mechanisms (up to 90% discount) and batch processing (50% discount). This makes the model accessible even for large projects with high query volumes.
Access Through Applications
In web application and mobile apps, models available to Max, Team and Enterprise tier users. For Max and Team Premium users, Anthropic removed special limits on Opus 4.5 and increased overall usage limits. Now approximately as many Opus 4.5 tokens are available as Sonnet had before.
The model is also available through cloud platforms: Amazon Bedrock, Google Vertex AI and Microsoft Azure. Each platform uses its own pricing, but base cost remains close to official $5/$25.
Claude Code and Other Products
Claude Code—autonomous coding agent from Anthropic—received two important updates with Opus 4.5 release. First is Plan Mode, where the model first asks clarifying questions, then creates an editable plan in the plan.md file, and only then starts execution. This reduces errors and lets the user control the process.
Second update—Claude Code now available in desktop application, allowing running multiple local and remote sessions in parallel. For example, one agent can fix bugs, second—research GitHub, and third—update documentation.
Claude for Chrome—browser extension allowing models to control tabs, fill forms and execute tasks on the internet—now available to all Max tier users. Claude for Excel, announced in October, received expanded access for Max, Team and Enterprise users.
What Opus 4.5 Is Best For
Complex programming tasks where need maximum accuracy and code quality. Refactoring large codebases, migrating projects between technologies, fixing complex bugs in multi-component systems.
Creating autonomous agents that can work for hours without human intervention. Anthropic reports model capable of maintaining task focus for over 30 hours.
Deep analysis and research using multiple sources. Extended thinking and a large context window allow the model to process complex multi-step tasks.
Working with office documents—presentations, spreadsheets, reports. Excel integration and file creation support make Opus 4.5 useful for business tasks.
Conclusion
Claude Opus 4.5 is the most powerful programming model for December 2025 with 80.9% result on SWE-bench Verified. Unique effort parameters, 66% price reduction and improved security make it an attractive choice for complex projects.
However, it is worth considering that for many tasks cheaper alternatives like Sonnet 4.5 ($3/$15) or GPT-5.2 ($2/$10) may be sufficient. Model choice depends on specific project requirements—budget, necessary accuracy and work volume.
Frequently Asked Questions (FAQ)
When was Claude Opus 4.5 released?
Claude Opus 4.5 was released November 24, 2025 by Anthropic. This is the newest and most powerful model in Claude lineup at release time.
How much does Claude Opus 4.5 cost?
Claude Opus 4.5 price is $5 per million input tokens and $25 per million output tokens. This is 66% cheaper than previous version Opus 4.1, which cost $15/$75. Additionally can get up to 90% discount when using prompt caching.
How does Claude Opus 4.5 differ from Sonnet 4.5?
Main differences: Opus 4.5 is more powerful (80.9% vs 77.2% on SWE-bench), has effort parameters for reasoning depth control and better handles long-term tasks. Sonnet 4.5 is faster, cheaper ($3/$15 vs $5/$25) and available with 1M token context in beta version.
What is the effort parameter in Claude Opus 4.5?
The effort parameter is a unique Claude Opus 4.5 feature allowing control of the model's reasoning depth. Three levels available: low (quick answers), medium (balance, saves 76% tokens) and high (maximum quality). This allows optimizing costs depending on task complexity.
What is Claude Opus 4.5 result on SWE-bench Verified?
Claude Opus 4.5 showed 80.9% on the SWE-bench Verified test—best result among all existing models. For comparison: GPT-5.2 ~78%, GPT-5.1 Codex Max—77.9%, Claude Sonnet 4.5—77.2%, Gemini 3 Pro—76.2%.
Is Claude Opus 4.5 available in GitHub Copilot?
Yes, Claude Opus 4.5 available in GitHub Copilot from November 24, 2025 for Pro, Pro+, Business and Enterprise tier users. The model can be selected in the model selection menu in VS Code, Visual Studio, JetBrains IDEs, Xcode and Eclipse.
What is the context window size of Claude Opus 4.5?
Claude Opus 4.5 context window is 200,000 tokens for input and up to 64,000 tokens for output. This is sufficient for processing large codebases, long documents and complex multi-step tasks.
Does Claude Opus 4.5 support images?
Yes, Claude Opus 4.5 supports working with images. The model can analyze screenshots, diagrams, graphs, tables and other visual data. This is useful for interface analysis, debugging from screenshots and working with presentations.
Is Claude Opus 4.5 safer than competitors?
Yes, according to Anthropic, Claude Opus 4.5 is the safest model in the industry. It showed best resistance to prompt injection attacks in Gray Swan tests and has minimal level of unwanted behavior. Model classified at ASL-3 safety level—most stringent at Anthropic.
Where can Claude Opus 4.5 be used?
Claude Opus 4.5 available through: Claude API (claude-opus-4-5-20251101), claude.ai web application, iOS and Android mobile apps, cloud platforms Amazon Bedrock, Google Vertex AI and Microsoft Azure, GitHub Copilot, Claude Code (desktop application), Claude for Chrome and Claude for Excel extensions.
Fedor Zhilkin
Dec 19, 2025
