Haiku 4.5 for production: where it actually wins
Haiku 4.5 punches above its price tier. Three patterns where swapping it in saves real money without quality loss.
Haiku 4.5 quietly became one of the most useful models in the lineup. It's fast, cheap, and — on the right tasks — within striking distance of Sonnet 4.6.
Three patterns where Haiku 4.5 wins
1. Sub-agent workers in fan-out
In an orchestrator-worker setup, the orchestrator wants strong reasoning (Sonnet 4.6 or Opus 4.7). The workers, doing narrow well-scoped subtasks, are perfect for Haiku 4.5. 80% of the cost reduction comes from this swap.
2. Classifiers and routers
Intent classification, sentiment, language detection, "is this a billing question or a tech question?" — Haiku 4.5 hits >95% on most production classifiers and runs at near-Sonnet latency.
3. Streaming UI hot paths
Autocomplete, inline suggestions, real-time summarization — wherever p99 latency is a hard constraint, Haiku 4.5 buys you headroom Sonnet doesn't.
Where Haiku 4.5 loses
- Multi-step reasoning over long inputs.
- Code generation longer than a few dozen lines.
- Anything that benefits from extended thinking.
Model ID: claude-haiku-4-5-20251001. The dated suffix matters — the exam tests model identifiers precisely.