---
title: "Chain-of-thought prompting"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "Chain-of-thought prompting"
aliases: ["chain of thought","CoT","CoT prompting"]
first_seen: "2026-05-26T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["reasoning models","Jason Wei","chain-of-thought faithfulness","competitive moats in AI","test-time compute"]
seek_code_commit: "17d9798"
---


The technique of eliciting a language model's step-by-step reasoning before
its final answer, shown by Wei et al. ("Chain-of-Thought Prompting Elicits
Reasoning in Large Language Models," 2022) to substantially improve
performance on arithmetic, commonsense, and symbolic reasoning tasks — and
the vocabulary the whole reasoning-model era descends from. What began as a
prompting technique for an otherwise-unchanged model became, in OpenAI's o1
and Anthropic's extended-thinking models, an architected capability the
model is trained to use.

Matters to this vault as the load-bearing concept behind an entire cluster of
notes about what reasoning traces are, whether labs show them to users, and
whether they can be trusted: OpenAI's decision to hide o1's raw trace while
showing a generated summary
([[claim-openai-hid-o1-raw-chain-of-thought-partly-for-competitive-advantage]],
[[claim-openai-o1-shows-model-generated-summary-of-chain-of-thought-not-raw-trace]]),
Anthropic's structurally similar choice for extended thinking
([[claim-extended-thinking-as-serial-inference-compute]]), the empirical
case that an exposed trace is cheap to distill from
([[claim-s1-distilled-reasoning-from-1000-traces-in-26-minutes]]), the
argument that a codified trace cannot form a tacit competitive moat
([[claim-a-chain-of-thought-trace-is-codified-so-it-cannot-form-a-tacit-moat]]),
and the open question of whether a visible trace faithfully reflects the
computation that produced it ([[cot-faithfulness-anthropic-biology]],
[[introspection-access-problem]]).

## References

- [[claim-openai-hid-o1-raw-chain-of-thought-partly-for-competitive-advantage]]
- [[claim-openai-o1-shows-model-generated-summary-of-chain-of-thought-not-raw-trace]]
- [[claim-extended-thinking-as-serial-inference-compute]]
- [[claim-s1-distilled-reasoning-from-1000-traces-in-26-minutes]]
- [[claim-a-chain-of-thought-trace-is-codified-so-it-cannot-form-a-tacit-moat]]
- [[cot-faithfulness-anthropic-biology]]
- [[introspection-access-problem]]