Lesson 3.2 · D3 Product & Model Selection · 4 min
Differentiate Haiku, Sonnet and Opus
The three tiers trade capability against speed and cost.
What the exam tests
Knowing which tier suits which kind of work. Model versions change; the tier logic is what's examined.
Key ideas
- Haiku
- Fastest and most economical. Suits high-volume, well-defined tasks: classification, routing, tagging, short extraction, real-time suggestions that people review.
- Sonnet
- The balanced choice for everyday drafting, summarising and analysis where both quality and responsiveness matter.
- Opus
- Most capable. Suits complex, high-stakes reasoning over long or conflicting material where quality matters more than speed or cost.
- Versions move on
- New generations arrive regularly; choose by tier characteristics, not by assuming “newest” or “largest” is always right.
Common traps
- “Always use the most capable model to be safe.”
- “Model choice doesn't matter.”
- Switching tiers to fix a problem that is really a vague prompt or missing context.
Remember
Haiku = volume and speed. Sonnet = everyday balance. Opus = hardest, highest-stakes thinking.