Claude Sonnet 4.5 is the best coding model in the world. It's the strongest model for building complex agents. It's the best model at using computers. And it shows substantial gains in reasoning and math.
Modalities
Context window
1,000,000
Pricing
input / output per 1M
Reasoning
Streaming
Real-time token-by-token response streaming
Function calling
Connect the model to external tools and systems
Structured outputs
Return responses in JSON schema format
Reasoning
Extended thinking before responding
Memory
Persistent memory across conversations
Context editing
Edit conversation context dynamically
Web search
Search the internet for real-time information
File search
Search and retrieve from uploaded files
Code execution
Execute code in a sandboxed environment
Computer use
Control and interact with computer interfaces
File creation
Create documents, spreadsheets, and slides
| SWE BENCH VERIFIED | 77.2 |
| OSWORLD | 61.4 |
| HIGH COMPUTE SWE BENCH | 82.0 |
| Release date | 2025-09-29 |
| Model ID | claude-sonnet-4.5 |
| Provider | Anthropic |