Anthropic’s New AI Powers Through Code: “World’s Best” Claude Sonnet 4.5 Debuts
Anthropic released Claude Sonnet 4.5 on Sept. 29, 2025, claiming it outperforms rivals in coding and complex agent tasks. The model ran autonomous coding sessions for over 30 hours in tests and set new records on SWE-Bench Verified benchmarks. GitHub and Microsoft 365 Copilot are integrating Sonnet 4.5. Pricing matches the previous version at $3 per million input tokens.