Chain-of-thought prompting is a technique that asks an AI model to reason through a problem step by step before giving its final answer, which often improves accuracy on complex tasks.
What is chain-of-thought prompting?
Chain-of-thought prompting asks a model to show its intermediate reasoning steps, not just its final answer. Instead of jumping straight to a conclusion, the model works through a problem the way a person might on scratch paper: breaking it into smaller steps, solving each one, and building toward the final result.
Why chain-of-thought improves accuracy
Language models generate one token at a time, and each token depends on everything generated before it. By producing intermediate reasoning steps first, the model effectively gives itself more "space" to work through a problem, which measurably improves performance on tasks like math word problems, logic puzzles, and multi-step decision-making compared to asking for a direct answer.
Chain-of-thought and reasoning models
This idea evolved from something researchers manually triggered with prompts like "let's think step by step" into a core part of how newer reasoning-focused models work: some models now generate extended internal chains of thought automatically before answering, without needing to be explicitly asked, trading extra inference time for higher accuracy on hard problems.
Limits of chain-of-thought prompting
Chain-of-thought reasoning can make errors just as confidently as a direct answer would, and a plausible-looking chain of steps doesn't guarantee a correct final answer. It also increases the number of tokens generated, which means it takes longer and costs more per response than a direct answer, so it's typically reserved for problems complex enough to benefit from it.