OpenAI Releases the o1 Reasoning Model

OpenAI introduced the o1 model family in September 2024 with a focus on spending more computation before producing an answer. The models were especially aimed at mathematics, coding, and scientific reasoning tasks.

Instead of immediately generating a short response, o1 used additional internal inference steps to work through difficult problems. This changed the cost model of language-model use: quality could improve by allocating more computation at answer time, not only by training a larger network.

The release made “test-time compute” a major AI research and product topic. It also created a practical trade-off for developers because harder reasoning could mean higher latency and cost. Fast chat responses and deep problem solving were becoming separate model-design targets.