claude-sonnet-4.5-20250929

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model, optimized for real-world agents and coding workflows. It achieves state-of-the-art results on coding benchmarks like SWE-bench Verified, with notable improvements in system design, code security, and following specifications. Designed for extended autonomous operation, the model maintains task continuity across sessions and offers fact-based progress tracking. Sonnet 4.5 features enhanced agentic abilities, such as improved tool orchestration, speculative parallel execution, and more efficient context and memory management. With better context tracking and awareness of token usage across tool calls, it excels in multi-context and long-running workflows. Key use cases include software engineering, cybersecurity, financial analysis, research agents, and other areas requiring sustained reasoning and tool use.