Claude Sonnet 5.5

Claude Sonnet 5.5 is the middle model in Anthropic's 5.5 line, released 2026-09-28. OpenRouter lists $2 per million input tokens and $10 output, a 1,000,000-token context, and text, image and PDF input. It is the same price as Sonnet 5, so the update does not change a budget. It is closed, with no downloadable weights. We would suggest it as the default for coding agents, support bots and document work, since it costs half the input price of Opus 5.5 and twenty times the input price of Haiku 5.5, which gives teams a sensible middle rung. Our Claude Code and Anthropic pages show where it is used by default. The main limit is that very hard reasoning jobs may justify the larger model, and tiny classification jobs do not justify this one. Prices and specifications come from the OpenRouter listing we checked on 31 October 2026, and we have not tested the model ourselves.