Claude Opus 5.5

Claude Opus 5.5 is Anthropic's larger Claude model in the 5.5 line, released 2026-09-22. OpenRouter lists a 1,000,000-token context, text, image and PDF input, text output, and a price of $4 per million input tokens and $20 output. That is cheaper than the earlier Opus 5, which listed at $5 and $25, so teams that priced the older model should recheck their budgets. It is closed and proprietary, so there are no weights to self-host; you reach it through Anthropic, a cloud marketplace or a gateway. We would suggest it for long, hard agent tasks where the cost of a wrong answer is higher than the cost of tokens, and Sonnet 5.5 for everyday work. The limit is price: at twice the input rate of Sonnet 5.5, it needs a reason to be the default. Prices and specifications come from the OpenRouter listing we checked on 31 October 2026, and we have not tested the model ourselves.