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Claude Haiku 5.5 is out, almost a year after Haiku 4.5. On paper, it was worth the wait. Per million tokens, for prompts up to 100K: Input: $0.10 (Haiku 4.5: $1) Output: $0.50 (Haiku 4.5: $5) Longer prompts cost half as much as on Haiku 4.5. Anthropic puts the average saving at around 75%.

I expect it to earn a place as a subagent on well-specified work: implementing a plan, triage in code review, codebase research. Sonnet and Opus keep complex agentic coding. Prompting guide tip: at low and medium effort it sometimes reports a change as done without running a check. Name the check.

Same update: Sonnet 5.5 cache reads drop from $0.20 to $0.10 per million tokens. Anthropic puts the saving at around 20% on most agentic work, in line with my own estimate. With Haiku taking the right subagent work, I expect my Claude Max plans to go much further.