Reasoning model (thinks step by step before answering, thinking depth)
Japanese 推論モデル
A reasoning model is an AI that works through a problem step by step before it answers. More thinking helps on hard problems, but takes more time and cost.
A reasoning model does not answer the moment it gets a question. It first breaks the problem into several steps in its head, then replies. It is like a student who writes the working on scrap paper instead of jotting down only the final answer to a hard maths problem. The amount of this inner thinking is called thinking depth, and some services let you pick low, medium or high.
Watch out The deeper it thinks, the slower the answer and the higher the cost can be. So many people keep it shallow for simple customer replies and deep for complex calculations or programming. Some services also count the inner thinking as usage, so check the price list.
Source: OpenAI API docs 'Reasoning models' · Anthropic docs 'Extended thinking'