Claude Haiku 5.5 is an announced but not yet released Anthropic model from the 5.5 generation. The only public source remains the Claude Opus 5.5 announcement of 22 September 2026, in which Anthropic said Claude Sonnet 5.5 and Claude Haiku 5.5 would reach users "in the coming weeks".
Anthropic has disclosed no specifications for the model: there is no API identifier, no pricing, no context window size, no knowledge cutoff and no benchmark results. No specific release date has been given either.
Under Anthropic's convention to date, the Haiku variant is the fastest and cheapest member of a generation, aimed at high-volume, low-latency tasks. For the 5.5 generation this has not been officially confirmed, so treating that role as settled would be an assumption rather than a fact. The reference point remains the released Claude Opus 5.5 at $4 per million input tokens and $20 per million output, with fast mode priced at $8 and $40. This entry will be completed after the model ships.
