Cheaper small models and two open-weight promises

Haiku 5.5 lowers short-request prices, while maximum-effort scores hide a trade-off

A queue of short summaries or classification requests is a plausible place to try Haiku. Replacing a larger agent on a difficult workflow is a different decision. The gap between medium and max effort shows why a launch leaderboard cannot predict the setting your application uses. Set effort explicitly and measure cost per accepted result, including retries and corrections. Repeated agent prompts may also benefit from Sonnet's separate cache-read cut without any model substitution. Check that your requests actually generate cache hits. The migration guide is useful for API compatibility, but its living checklist supplies current integration advice rather than proof that every detail was already published at launch.