Xiaomi's HarnessX rewrites its own AI scaffolding mid-task — and smaller models gain the most

As enterprise AI agents take on increasingly complex, long-horizon tasks, their performance is often restricted by their harness, the software scaffolding that connects the backbone LLM to its environment. Currently, harnesses are largely static and hand-crafted. Improving them is largely manual and they do not automatically improve based on the execution data they collect from their environment.To address this engineering bottleneck, researchers at Xiaomi introduced HarnessX, a framework that treats the AI harness as a composable object and autonomously applies improvements to its code. In real-world enterprise applications, this automated adaptation enables AI systems to dynamically adjust to application-specific requirements. Practical tests showed HarnessX delivering substantial perfor…