// Adapt the Interface, Not the Model //
I am fascinated by the results across my cheap-model-plus-good-harness builds.
This new paper also shows good signs of the code-as-agent-harness thesis.
The idea is really simple. Do not touch the model. Instead, modify the runtime interface that wraps the frozen LLM. Then convert recurring interaction failures into reusable interventions on the harness side.
The paper reports an average relative improvement 88.5% across 7 deterministic environments, 126 model-environment settings, and 18 backbones.
A harness learned from one model trajectory generalizes to 17 other backbones. That tells you the harness is capturing environment structure, not model-specific patterns.
If you ship agents in production, your harness work is more portable than you might assume.
Paper: https://arxiv.org/abs/2605.22166
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