Claude Opus 4.1

Claude Opus 4.1 is Anthropic's most powerful AI model released in August 2025, excelling at complex reasoning, programming, and agentic tasks with 200K context window.

ClaudeAnthropicLanguage ModelLarge Language ModelAI AssistantFrontier ModelOpus
Developer
Anthropic
Type
Language Model
License
Proprietary
🌐 Official Website💰 Pricing & API

Overview

Claude Opus 4.1 is the latest flagship model from Anthropic, released on August 5, 2025. Positioned at the frontier of AI intelligence, it represents a significant upgrade over its predecessor, offering state-of-the-art performance, enhanced capabilities for complex reasoning, and groundbreaking proficiency in programming and agentic tasks. It is designed for enterprise clients and developers who require the highest level of AI performance.

Capabilities

Claude Opus 4.1 sets a new standard for AI performance across several key areas:

  • Frontier Intelligence: Provides top-tier performance on highly complex tasks, including advanced analysis, financial modeling, and research.
  • Advanced Programming: Demonstrates exceptional coding abilities, capable of writing, debugging, and optimizing complex codebases. It can operate as an independent software development agent for extended periods.
  • Multi-step Reasoning: Excels at breaking down complex problems and executing long chains of thought to arrive at accurate solutions.
  • Agentic Tasks: Can reliably perform complex, multi-step tasks autonomously over long durations, making it ideal for automation workflows.
  • Vision and Image Understanding: Possesses strong capabilities in analyzing and interpreting images, charts, and diagrams.

Technical Specifications

Claude Opus 4.1 is built on Anthropic's cutting-edge research in AI safety and performance:

  • Model size: Parameter count is not publicly disclosed, but it represents one of Anthropic's largest and most capable models.
  • Context window: 200K tokens (~150,000 words), enabling comprehensive analysis of large documents, entire codebases, and extended conversations.
  • Training data: Trained on a vast and diverse proprietary dataset with knowledge up to April 2025.
  • Architecture: Advanced Transformer-based architecture incorporating Constitutional AI principles for enhanced safety and alignment.
  • Response quality: Optimized for accuracy, nuance, and reliability in complex tasks.

Use Cases

Claude Opus 4.1 is engineered for the most demanding enterprise and developer applications:

  • Autonomous Software Development: Acting as an AI agent to handle complex coding tasks, from architecture design to implementation, testing, and debugging across multiple programming languages.
  • Strategic Analysis: Conducting comprehensive market research, financial modeling, competitive intelligence, and scenario planning for executive decision-making.
  • Scientific Research: Accelerating R&D by analyzing research papers, experimental data, and complex datasets; generating hypotheses and research methodologies.
  • Enterprise Automation: Powering sophisticated, multi-step workflows including document processing, data extraction, report generation, and cross-system integration.
  • Legal and Compliance: Analyzing contracts, regulatory documents, and compliance requirements with high accuracy and attention to detail.
  • Technical Documentation: Creating and maintaining comprehensive technical documentation, API references, and knowledge bases.

Performance Metrics

Based on comprehensive evaluations, Claude Opus 4.1 demonstrates exceptional performance across key benchmarks:

  • Graduate-level Reasoning (GPQA Diamond): State-of-the-art performance on highly complex reasoning tasks requiring advanced domain knowledge
  • Advanced Mathematics (MATH): Exceptional performance on challenging mathematical problems and proofs
  • Professional Coding (HumanEval, SWE-bench): Leading performance on software engineering benchmarks and real-world coding tasks
  • Multilingual Understanding: Superior performance across 100+ languages with nuanced cultural and linguistic understanding
  • Complex Problem Solving: Exceptional ability to break down and solve multi-step, interdisciplinary problems
  • Agentic Task Execution: Reliable performance on autonomous, long-duration tasks requiring sustained reasoning

Limitations

Despite its advanced capabilities, Claude Opus 4.1 has some constraints to consider:

  • Cost: As a frontier model, it commands a premium price ($0.015/$0.075 per 1K tokens) compared to Claude Sonnet 4.5 ($0.003/$0.015 per 1K tokens) or Haiku models, making it best suited for complex tasks that justify the investment.
  • Speed: While highly capable, response times are longer than faster models like Sonnet or Haiku. For simple queries or high-throughput applications, consider using lighter models.
  • Knowledge Cutoff: Training data extends only through April 2025. For real-time information, current events, or recent developments, external tools or web search integration is required.
  • No Internet Access: Cannot browse the web or access external databases unless integrated through function calling or tool use.
  • Resource Intensive: Higher computational requirements mean it's not suitable for edge deployment or resource-constrained environments.

Safety & Alignment

Claude Opus 4.1 represents a significant advancement in AI safety and alignment:

  • AI Safety Level 3: Deployed under ASL-3 Standard with substantially improved safety profile
  • Enhanced Safeguards: Improved refusal rates for harmful requests while maintaining low false positive rates
  • Agentic Safety: Advanced safety measures for autonomous task execution and tool use
  • Cybersecurity: Comprehensive evaluation of cyber capabilities with appropriate safeguards
  • Alignment Research: Novel mechanistic interpretability methods for understanding model behavior
  • Third-Party Testing: Evaluated by UK AISI and Apollo Research for independent safety assessment

Evaluation & Testing

Claude Opus 4.1 underwent comprehensive evaluation using advanced testing methodologies:

  • Mechanistic Interpretability: First-time use of mechanistic interpretability methods for alignment testing
  • Behavioral Audits: Automated behavioral audits with realism filtering and open-ended evaluation runs
  • Multi-Turn Testing: Comprehensive assessment of model behavior across extended conversations
  • Reward Hacking Evaluations: Testing for potential reward manipulation and optimization gaming
  • Model Welfare Assessment: Investigation of model preferences and welfare-relevant expressions
  • Responsible Scaling Policy: Mandated evaluations for dangerous weapons and autonomous AI R&D risks

Cybersecurity Capabilities

Claude Opus 4.1's cybersecurity capabilities were thoroughly evaluated:

  • CyberGym Evaluations: Comprehensive testing of vulnerability discovery and exploit development
  • Cybench Challenges: Assessment of attack orchestration capabilities across multiple domains
  • Triage and Patching: Evaluation of security response and vulnerability management capabilities
  • Advanced Risk Assessments: Testing for irregular challenges and sophisticated cyber scenarios
  • Defense-Enabling Focus: Emphasis on defensive cybersecurity capabilities over offensive uses
  • Ongoing Monitoring: Continuous assessment of cyber capabilities as AI systems advance

CBRN Risk Evaluations

Comprehensive assessment of risks related to chemical, biological, radiological, and nuclear capabilities:

  • Chemical Risk Assessment: Evaluation of potential assistance with chemical weapon development
  • Biological Risk Analysis: Testing for virology knowledge and biological engineering capabilities
  • Radiological & Nuclear: Assessment of nuclear technology and radiological material knowledge
  • DNA Synthesis Screening: Evaluation of potential to evade screening for dangerous biological materials
  • Long-Form Virology Tasks: Complex biological research task assessments
  • Creative Biology: Testing for novel biological engineering capabilities
  • Computational Biology: Short-horizon bioinformatics task evaluations

Ongoing Safety Commitment

Anthropic maintains continuous safety monitoring and improvement:

  • Pre & Post-Deployment Testing: Regular safety testing of frontier models before and after release
  • Methodology Refinement: Continuous improvement of evaluation methodologies through research
  • External Collaboration: Ongoing partnerships with external organizations for independent assessment
  • Iterative Safety Measures: Regular updates to safety protocols as AI capabilities advance
  • Responsible Development: Commitment to responsible AI development practices and transparency

Pricing & Access

Claude Opus 4.1 offers flexible pricing options for both individual users and developers:

Individual Plans

  • Free: $0 - Basic access to Claude with web, mobile, and desktop apps
  • Pro: $20/month - Enhanced productivity features and more usage
  • Max: From $100/month - Maximum usage limits and early access to advanced features

API Pricing

Available via the Anthropic API, Amazon Bedrock, and Google Cloud's Vertex AI:

  • Input:
    • $15 / MTok (prompts ≤ 200K tokens)
    • $30 / MTok (prompts > 200K tokens)
  • Output:
    • $75 / MTok (prompts ≤ 200K tokens)
    • $112.50 / MTok (prompts > 200K tokens)
  • Prompt Caching: Available for cost optimization on longer conversations

Ecosystem & Tools

Claude Opus 4.1 integrates seamlessly with modern development workflows:

Official SDKs

  • Python SDK: Full-featured library with async support
  • TypeScript SDK: Type-safe integration for Node.js and browsers
  • REST API: Direct HTTP access for any programming language

Developer Tools

  • Anthropic Console: Web-based playground for testing and prompt development
  • Workbench: Advanced prompt engineering and evaluation environment
  • Claude.ai: Browser-based interface for direct interaction

Integrations

  • LangChain: Native support for chain-of-thought and agent workflows
  • LlamaIndex: Integration for RAG (Retrieval-Augmented Generation) applications
  • CrewAI: Multi-agent orchestration platform
  • Function Calling: Built-in support for tool use and external API integration

Community & Resources

Frequently Asked Questions

Claude Opus 4.1 was released by Anthropic on August 5, 2025.
Claude Opus 4.1 excels in frontier intelligence tasks, complex reasoning, advanced programming, and agentic task execution. It represents Anthropic's most powerful model designed for the most demanding enterprise applications requiring maximum AI performance.
Claude Opus 4.1 is Anthropic's most powerful model for tasks requiring maximum intelligence and complex reasoning, while Sonnet 4.5 is faster and more cost-effective, designed for high-throughput enterprise applications with enhanced reasoning capabilities.
Claude Opus 4.1 is deployed under AI Safety Level 3 (ASL-3) Standard with substantially improved safety profile. It underwent comprehensive evaluation including mechanistic interpretability testing, behavioral audits, and third-party assessment by UK AISI and Apollo Research.
Claude Opus 4.1 supports 200K tokens context window, enabling comprehensive analysis of large documents, entire codebases, and extended conversations. This allows for deep analysis of complex, multi-step problems.
Claude Opus 4.1 is priced at $0.015 per 1K input tokens and $0.075 per 1K output tokens. It's available via Anthropic API, Amazon Bedrock, and Google Cloud's Vertex AI.
Claude Opus 4.1 achieves state-of-the-art performance on graduate-level reasoning (GPQA Diamond), advanced mathematics (MATH), professional coding (HumanEval, SWE-bench), and multilingual understanding across 100+ languages. It excels at complex reasoning and agentic task execution.
Claude Opus 4.1 underwent comprehensive cybersecurity evaluation including CyberGym assessments, Cybench challenges, and advanced risk evaluations. It focuses on defense-enabling capabilities with ongoing monitoring of cyber risks.
Claude Opus 4.1 can operate as an independent software development agent for extended periods, handling complex coding tasks from architecture design to implementation, testing, and debugging across multiple programming languages with exceptional accuracy.

Related Models

Claude Sonnet 4.5

Anthropic's latest high-performance AI model, delivering enhanced reasoning and improved performance for enterprise workloads and scaled AI applications.

Gemini 2.5

Google's latest and most advanced multimodal model, with enhanced reasoning, a 1M+ token context window, and improved performance.

GPT-5

OpenAI's most advanced language model with superior reasoning, multimodal capabilities, and enhanced safety features.

Llama 4

Meta's open-source family of AI models, featuring specialized versions like Scout and Maverick, designed to lead in reasoning, coding, and multimodality.

Explore More Models

Discover other AI models and compare their capabilities.

Browse Models← Back to Models