Anthropic Releases Sonnet 4.6 With 1M Context Window

Anthropic released Claude Sonnet 4.6 this month, the first Sonnet upgrade since version 4.5 arrived in September 2025, featuring a 1M-token context window. The company says Sonnet 4.6 improves coding, computer use, long-context reasoning, agent planning, knowledge work and design, delivering Opus-class performance on many office tasks. Sonnet 4.6 is now the default for free-tier Claude users and includes file creation, connectors, skills, and compaction.