AREX agentic research model checks answers requirement by requirement
The standout finding is that verification-driven harness design, not raw model scale, drives much of the gain, since the harness alone added up to 10 points and a 4B fine-tune outperformed a 35B baseline. Teams building research agents can replicate the check-gaps-research loop without large models. It offers a concrete benchmark point against other deep-research agent stacks.
