02 · Model Architectures

Reasoning Model

Trained to think before answering

A model optimized to spend additional inference compute on multi-step reasoning before returning a final answer. Some systems generate hidden reasoning tokens or use repeated sampling and search; extra compute can improve difficult math, logic, and coding tasks, but not uniformly.

Concrete example

Given a tricky logic puzzle, a reasoning model can spend more compute testing intermediate steps before it returns an answer.

Why it matters

Since 2024, test-time compute has become a major axis of model development alongside larger training runs.

Evidence

Sources for this definition

  1. 1
    Learning to reason with LLMs

    OpenAI · Announcement · checked 2026-07-13