The agent harness

The agent harness
Why agent demos break in production, and why the harness, the state, gates, traces, verification, and engineering around the model, is often the actual product.
Author

Yee Seng Chan

Published

2026 · April 14

A demo agent and a production agent run the same model. The difference is everything around it: how state is carried, where the run is gated, what gets traced, how output is verified before it is trusted. This series argues that this scaffolding, the harness, is usually where reliability is won or lost.

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