Simon Willison’s Weblog

[...] The disappointing releases of both GPT-4.5 and Llama 4 have shown that if you don't train a model to reason with reinforcement learning, increasing its size no longer provides benefits.

Reinforcement learning is limited only to domains where a reward can be assigned to the generation result. Until recently, these domains were math, logic, and code. Recently, these domains have also included factual question answering, where, to find an answer, the model must learn to execute several searches. This is how these "deep search" models have likely been trained.

If your business idea isn't in these domains, now is the time to start building your business-specific dataset. The potential increase in generalist models' skills will no longer be a threat.

— Andriy Burkov