Harness Engineering: Build the 6 Layers Backwards (6→1, Not 1→6)

Sat, 18 Apr 2026 16:00:00 +0800

The 6 layers of Harness Engineering are not equal.

That sentence breaks the standard advice. Every talk, every framework diagram, every “what is Harness Engineering” explainer puts the 6 layers in a tidy stack and tells you to build them in order: Context → Tools → Execution → Memory → Evaluation → Recovery. Sensible, easy to teach, completely wrong if you actually want a stable agent in production.

Production AI on Bruce on AI Engineering

Harness Engineering: Build the 6 Layers Backwards (6→1, Not 1→6)