# Agent harnesses are changing, not dying, as Harness-Zero trains harness behavior into a model

> Original title: Are agent harnesses dying? What harness distillation changes.

- Source: O'Reilly Radar
- Published: 2026-10-27T10:54:38.000Z
- Bad Influence: https://badinfluence.news/items/ankm7tb17058yekyqukz4qec0
- Original: https://www.oreilly.com/radar/are-agent-harnesses-dying-what-harness-distillation-changes/

## Summary

A Peking University research team trained a small model, Qwen3.5-9B, on corrected runs produced by a harness, then removed the harness. The distilled model's average task success rose 21 points over its untrained predecessor, beating the model-plus-harness combination. The article argues that harnesses remain necessary for tools, data, users, and environment, and that teams should tag traces with harness and model versions, then disable components one at a time when a new model ships.