Lightweight o4-mini activates after users hit usage limits, offering shorter but thorough answers with 45.6% accuracy compared to deep research’s 51.5%.

OpenAI is introducing a new version of its ChatGPT deep research tool that it says is cheaper to operate. The “lightweight” model is available now to free users, as well as those on several of the company’s paid tiers.

Creating a new kind of deep research tool is an attempt from OpenAI to reduce the heavy usage of existing deep research modes it's seeing from users. These kinds of queries can be more expensive for AI providers to execute, due to their process of running more complicated commands and returning more information.