Phase 1 · Building with LLMs · Prompting
Reasoning models and effort
When models think before answering, and how to control it.
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Why it matters
Modern models can think before they answer. They work through a problem in private, then write the reply. That's why they can now plan an analysis, fix broken code or weigh the options in a brief. But thinking costs tokens, and tokens cost time and money. You can set how hard the model thinks, one task at a time. That setting is one of the biggest levers you have on quality, speed and cost.
What you'll be able to do
- Explain what thinking is and why it improves answers to hard problems
- Set the effort level on a request and choose it for a task
- Read thinking blocks in a response, and ask for readable summaries
- Budget max_tokens and cost for requests that think
Inside this lesson
- 11 short sections
- 4 code examples you can edit and run
- a practice exercise that checks your code
- a 5-question quiz
- 4 review cards for spaced repetition
What it covers
- What thinking is
- Adaptive thinking and effort
- Reading thinking in a response
- Thinking costs tokens
- Worked example: what does more effort cost?
- Keeping thinking blocks in conversations
A taste of the code
body = {
"model": "claude-opus-5-5",
"max_tokens": 8000,
"output_config": {"effort": "low"}, # low, medium, high, xhigh or max
"messages": [{"role": "user", "content": "Tag this review: 'Arrived chipped.'"}],
}
Try a quiz question
You run 200,000 review-tagging requests a day on Claude Opus 5.5 and they're slower than you'd like. What should you try first?