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Chain of thought

Chain of thought is the step-by-step reasoning a model can work through before it answers.

Prompting 4 min read Updated 2026-05-22
— Definition

Chain of thought, in plain words

Chain of thought is the step-by-step reasoning a model can work through before it answers.

Present chain of thought as a reasoning trigger, not a magic trick.

A concrete example

I type "solve this problem step by step, show me your reasoning before you answer." The quality jumps up a notch.

Why it matters

This is the technique that unlocked models on math, code, and logic. Every reasoning model rests on it.

You mostly hear it around logic, planning, math, and reasoning models.

Don't mix it up with

Reasoning model: A reasoning model takes more time to think before answering a complex task.

Prompt engineering: Prompt engineering means phrasing a request with enough context, examples, and constraints to get a useful answer.

Common mistakes

  • Assuming every task benefits from chain of thought.
  • Forgetting it burns a lot more output tokens.
  • Thinking a model that reasons is automatically more accurate (sometimes it reasons badly).

Quick checklist

  • First I check whether the word names a concept, a tool, a risk, or a metric.
  • I tie it to a concrete case: I type "solve this problem step by step, show me your reasoning before you answer." The quality jumps up a notch.
  • I keep the main trap in mind: Assuming every task benefits from chain of thought.

Quick questions

What is Chain of thought in AI?

Chain of thought is the step-by-step reasoning a model can work through before it answers.

Where will I run into Chain of thought?

You mostly hear it around logic, planning, math, and reasoning models.

Which word should I read next?

Start with Reasoning model, Prompt engineering, Reasoning effort.

Want to keep going in order?

Head back to the full glossary, search a word, then open only the pages that deserve more than a short definition.

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