Claude Haiku 5.5 Cuts Small-Model Prices to One Tenth of Haiku 4.5 and Jumps From 15.7% to 72.4% on OSWorld

Anthropic released Claude Haiku 5.5 on October 7, nine days after Claude Sonnet 5.5. The release completes the 5.5 family and replaces Haiku 4.5, the model at the center of this week's Philadelphia incident. The price is $0.10 per million input tokens and $0.50 per million output tokens for prompts up to 100,000 tokens. Above that length the price rises to $0.50 and $2.50. Cache reads start at $0.01 per million tokens, and batch requests cost half. That is one tenth of Haiku 4.5's list price, and Anthropic says real workloads come out about 75% cheaper on average. Context grows from 200,000 to one million tokens, with output up to 128,000 tokens and a June 2026 knowledge cutoff.

Anthropic's own benchmark numbers show the largest gains on agentic tasks. On the offline subset of OSWorld 2.1, the score rises from 15.7% to 72.4%. On Terminal-Bench 4.0, Haiku 5.5 scores 39.2%, compared with 0% for Haiku 4.5, 16.4% for OpenAI's GPT-6 Luna and 70.6% for Sonnet 5.5. It scores 64.8% on SWE-Bench Pro. On SWE-bench Multilingual it scores 83.7%, against Haiku 4.5's 67.4%, a smaller gain than the agentic tests show. These numbers come from the vendor. The one independent figure so far is Artificial Analysis's Intelligence Index score of 43 at maximum effort, second of 182 models in its price class.

The price cut puts downward pressure on the rest of the market. Sonnet 5.5 already lists at $2 input and $10 output and runs about 30% faster than Sonnet 5. Meta entered paid APIs with Muse Spark 1.1 at $1.25 and $4.25, a price reported as roughly a quarter of what OpenAI and Anthropic charged at the time. Haiku 5.5 now costs less than Muse Spark on both input and output for prompts under 100,000 tokens. Practitioners should note that the price rises fivefold above that length, so the advertised long context carries a separate price curve.