Anthropic launches Claude Sonnet 5 as a cheaper agentic model

Claude Sonnet 5 launches at $2/M input tokens and $10/M output tokens through August 31, then $3/$15. It promises performance close to Opus 4.8 while being cheaper than GPT-5.5 and Gemini 3.1 Pro, with significant improvements over Sonnet 4.6 in agentic coding (63.2% vs 69.2%).