# Chain-of-thought prompting

> Asking a model to work through intermediate reasoning steps before giving its final answer, which helps on multi-step problems.

Source: Promptea — https://www.promptea.me/en/glossary/chain-of-thought · Language: English · Last updated: 2026-11-09

## What it means

- Definition: instead of jumping to an answer, the model writes out the steps — restating the problem, working through the logic, then concluding. The technique is usually triggered with a phrase such as 'think step by step' or a structure with a reasoning block and an answer block.
- Why it matters: on multi-step math, logic and planning, errors compound when the model answers in one hop; showing the steps makes them less likely and lets you see where the reasoning broke.
- How to apply it: ask for the reasoning first and the final answer last, keep the two separated (for example in tags) so a program can read only the answer, and ask it to check its work before concluding.
- Common mistake: adding it by reflex. Models that reason internally often do not need an explicit 'think step by step', and extra process instructions can get in their way — see the guide on reasoning models and check the provider's advice for the model you use.

## Example

```text
Problem: [describe the problem]

First, inside <reasoning> tags: restate what is asked, list what is known and what is missing, then work through the logic in small steps.
Then, inside <answer> tags: give only the final answer in one or two sentences.
Before the answer, check your reasoning for a mistake.
```

[Open in Promptea](https://www.promptea.me/en/analyzer?prompt=Problem%3A+%5Bdescribe+the+problem%5D%0A%0AFirst%2C+inside+%3Creasoning%3E+tags%3A+restate+what+is+asked%2C+list+what+is+known+and+what+is+missing%2C+then+work+through+the+logic+in+small+steps.%0AThen%2C+inside+%3Canswer%3E+tags%3A+give+only+the+final+answer+in+one+or+two+sentences.%0ABefore+the+answer%2C+check+your+reasoning+for+a+mistake.&purpose=text&target=claude)

## Frequently asked questions

### Does chain-of-thought always improve accuracy?

No. It helps most on multi-step problems. For simple lookups or classification it adds length and cost without much benefit.

### Should I show the reasoning to end users?

Usually not. Keep reasoning and answer in separate blocks and display only the answer; use the reasoning for debugging.

## Related

- [Chain-of-thought prompting: make the model show its reasoning](https://www.promptea.me/en/guides/chain-of-thought)
- [How to prompt reasoning models (GPT-6, Claude Opus 5.5, Gemini, Grok, DeepSeek)](https://www.promptea.me/en/guides/reasoning-model-prompts)
- [How to debug a prompt that gives bad output](https://www.promptea.me/en/guides/prompt-debugging)
- [Prompt chaining](https://www.promptea.me/en/glossary/prompt-chaining)
- [Zero-shot prompting](https://www.promptea.me/en/glossary/zero-shot)