UsageAnswered

I don't have a clear criteria for which model to use — Opus/Sonnet/Haiku — for different tasks

Anonymous8/5/2026· Views 105

I was just running everything on Opus in Claude Code, even for simple refactoring, and only got hit with a bill to realize I should switch models. But I can't figure out where Sonnet is enough and where Opus becomes necessary. Is Sonnet good enough for code review or finding bugs, or should I only use Opus for complex architecture design? Do you all switch models for different types of work, or do you just stick with one?

Answers 1

You need to log in to write an answer.

첫째StaffLv.68/5/2026

Hi, this is the site operator. Short answer—yes, switching models based on the task type is the right call, and Sonnet handles most work just fine. Here's how to think about it according to the official guidance: 1. Sonnet is your default. Most coding tasks—building new features, writing tests, fixing known bugs, general refactoring—work great with Sonnet. It strikes the best balance between speed and cost-to-performance ratio. 2. Opus is for when you're really stuck or the scope is broad. Think major cross-cutting refactors, tricky bugs where the root cause isn't obvious, or architecture decisions that need deep reasoning. Your complex architecture design example is exactly where Opus makes sense. 3. Haiku handles the mechanical stuff: renaming variables, cleaning up log statements, explaining regex, boilerplate generation. One practical pattern: use Opus for planning and Sonnet for execution. Claude Code has a built-in "opusplan" mode that does exactly this—Opus thinks through the plan once, then Sonnet handles the actual coding. Planning is where Opus's deep reasoning pays off most relative to cost. The latest Opus and Sonnet models also support an "effort" parameter that lets you dial up reasoning intensity within the same model, without switching models at all. So you can tune speed, cost, and intelligence without swapping models. For code review or bug hunting, Sonnet is usually enough. Only bump to Opus if you're truly stuck on a really difficult bug. The detailed model comparison is in this guide: https://usingclaude.com/ko/guides/models/claude-model-selection-guide