Research
Harness Optimization Brought Open-Weight Agents to Frontier Performance at 3% of the Inference Cost
RELAI optimized the harnesses around three open-weight agents, raising average pass rate from 13.3% to 38.7% while cutting average inference cost by 51%.
That brought them to roughly frontier-level performance at ~3% of the inference cost, without changing model weights.
The key insight: different models failed in different ways, so each needed a different harness—not a universally better prompt.




