Haiku 5.5's Price Sheet Is Not Its Bill
Matching a rival's per-token price means little when a model reasons longer, counts text differently and charges five times as much past a context line.
Where the discount leaks out
Three mechanics sit between the headline price and your invoice. The first is token burn. Artificial Analysis found that Haiku 5.5 needs about 55,000 output tokens to match GPT-6 Luna's index score of 38. Luna needs 50,000. Haiku's five-point lead at maximum effort costs about 162,000 tokens, roughly three times what Luna uses at the same per-token price.
The second is counting. Anthropic's new tokenizer counts the same text as roughly 25-30% more tokens. Reasoning defaults to medium and cannot be fully turned off. The third is the context cliff. Above 100,000 tokens, Haiku charges $0.50 for input and $2.50 for output. Haiku matches Luna's list price only below 100,000 tokens, so for longer prompts Luna can be cheaper at list price.
Independent evaluators already see the effect. Vals found that Haiku 5.5 costs more per test than Haiku 4.5 on every benchmark the two share. On one legal research task it took 59 reasoning steps where its predecessor took 17. This is how Cursor can call the model "10x cheaper" for short coding requests while Anthropic claims "75% cheaper on average." Both can be true. The shape of your workload decides which one you get.
Counting requests instead of dollars
Anthropic says about 90% of Haiku 4.5 requests fit under the 100,000-token line. That figure counts requests, not dollars, and long prompts carry most of the tokens. Take an illustrative mix of 90 short requests at 10,000 tokens and 10 long ones at 300,000. The long requests make up about 94% of input spend. If your agents load whole documents into context, the headline cut may barely touch your bill.
Why it is still worth taking
None of this makes Haiku 5.5 a bad buy. It leads its tier on agentic coding, scoring 33% on Terminal-Bench against Luna's 13%. It also beat Sonnet 5 on Devin's FrontierCode at about one-eighth the cost per task. Anthropic halved Sonnet 5.5 cache reads to $0.10 per million tokens, which it says makes long-running agent work about 20% cheaper. GitHub Copilot and Devin already run Haiku as the worker beneath an Opus or Sonnet lead.
One gap is temporary but real. An over-refusal bug currently holds Haiku's automation score at 35%, against 53-60% for its rivals, until Artificial Analysis re-runs the test.
Expect the price war to continue. Observers are openly calling on OpenAI to respond. The Information also reports, in a headline without detail, that Microsoft cut its internal Claude spending by about a third, so even the largest buyers shop around. The advantage goes to whoever can re-benchmark fastest. A price cut only helps companies that can evaluate and re-route a workload within weeks.
A model that matches a rival's price per token can still cost three times as much per finished task.
The smart move
Make model selection a recurring, measured decision owned by one team rather than a one-time purchase. Price every workload on cost per completed task at its real context length. Set context and effort limits by policy instead of leaving them to individual engineers. Keep contracts short enough to capture the next price cut.
What to do
Commission a 30-day bake-off of Haiku 5.5, GPT-6 Luna and Gemini on your top three high-volume AI workloads, scored on cost per completed task at real context lengths, ending in one decision memo.
Issue a company-wide AI usage policy this quarter: keep worker calls under 100K tokens, set a default effort level for each workload class, and allow maximum effort only by exception.
Cap new model commitments at 12 months with price-protection clauses, and keep two vendors live in production for every critical workload.