Scale and Selection: What Makes Automatic Harness Evolution Work for Visual-Interface Robot Agents
arXiv:2609.39304v2 Announce Type: replace-cross Abstract: When an off-the-shelf coding agent is used directly as a robot policy, observing a browser-based 3D interface through screenshots and acting by posing a virtual target gripper through a few tools, the agent's harness, its prompts, tools, and control rules, largely determines success, and until now it has been written by hand. We show that this harness can be improved automatically by another coding agent, the optimizer agent, and report…