Claude Sonnet 4.5
It's the strongest model for building complex agents. It's the best model at using computers. And it shows substantial gains on tests of reasoning and math.
README.md
Claude Sonnet 4.5
Release Date: September 29, 2025
Context Window: 200K tokens
Model Type: Hybrid Reasoning Model
Developer: Anthropic
🚀 Overview
Claude Sonnet 4.5 is Anthropic’s most advanced hybrid reasoning model, offering superior intelligence for agents, enhanced coding and computer-use capabilities, and a massive 200K context window.
Designed for long-running tasks and intelligent multi-agent systems, Sonnet 4.5 brings state-of-the-art performance in coding, finance, cybersecurity, and research—while maintaining exceptional reliability and safety.
🧠 Key Features
- Hybrid Reasoning Architecture: Combines symbolic and neural reasoning for deeper understanding and planning.
- 200K Context Window: Handle large documents, repositories, and multi-step workflows effortlessly.
- Enhanced Agent Intelligence: Optimized for long-running agents and complex tool use.
- Superior Coding Capabilities: Industry-leading performance in code generation, debugging, and refactoring.
- Advanced Domain Knowledge: Expanded expertise in finance, cybersecurity, and business automation.
- Fine-Grained Thinking Control: Adjust reasoning depth and latency for API use cases.
💡 Use Cases
🧩 Agentic Workflows
Build long-running, autonomous agents with advanced reasoning, tool selection, and self-correction capabilities.
💻 Code Generation
Powerful for end-to-end software development—planning, implementation, debugging, maintenance, and large-scale refactors.
Supports outputs up to 64K tokens for comprehensive codebases and architecture planning.
🌐 Computer & Browser Use
Industry leader in browser-based automation and computer control.
Handles complex workflows like competitive analysis, procurement, and customer onboarding with precision.
🛡 Cybersecurity
Use Claude Code agents to autonomously detect and patch vulnerabilities, transitioning from reactive to proactive defense.
💰 Financial Analysis
Automate regulatory monitoring, predictive modeling, and intelligent risk management across global data streams.
🧾 Business Tasks
Generate and edit documents, slides, and spreadsheets with professional accuracy and tone control.
🔍 Research
Integrate internal and external data for deep synthesis and cross-domain insight generation.
✍️ Content Generation & Analysis
Write, edit, and analyze content with nuanced understanding of style, tone, and context.
📊 Benchmarks
| Benchmark | Metric | Result |
|---|---|---|
| SWE-bench Verified | Coding | 77.2% |
| OSWorld | Computer Use | 61.4% |
Sonnet 4.5 sets new records for agentic reasoning, coding accuracy, and real-world computer interaction.
💻 Availability & Pricing
Claude Sonnet 4.5 is available on:
- Claude.ai (Web, iOS, and Android)
- Claude Developer Platform
- Amazon Bedrock
- Google Cloud Vertex AI
Pricing:
- $3 / million input tokens
- $15 / million output tokens
- Up to 90% savings with prompt caching
- Up to 50% savings with batch processing
Learn more on the pricing page →
🔒 Trust & Safety
Anthropic has conducted extensive testing and evaluation of Sonnet 4.5 with external experts to ensure:
- Safety and reliability in real-world deployment
- Security for sensitive data and autonomous agents
- Compliance with industry best practices
More details are available in the official Model Card.
📚 Previous Versions
| Model | Release Date | Highlights |
|---|---|---|
| Claude Sonnet 4 | — | Major coding improvements over 3.7; strong all-around performance. |
| Claude Sonnet 3.7 / Claude Code | Feb 24, 2025 | First hybrid reasoning model; state-of-the-art coding and planning. |
🧭 Quick Links
🏁 Summary
Claude Sonnet 4.5 represents the frontier of intelligent agents, coding assistance, and reasoning.
It’s the world’s best model for agents, coding, and computer use—built for developers and enterprises that demand reliability, intelligence, and depth.
© 2025 Anthropic. All rights reserved.
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