Learnings from harness engineering

2026-10-15 · offering

My coding harness gets stuck in local optima, and that creates long lead times. Each task is a small change that merges only if every test passes. Agents patch around the existing structure.
When a feature needs a structural change, progress slows because the required breakage does not fit inside one passing task.
I pause the harness and make the larger structural change myself, or ask for it directly.
It breaks many things at once. Then I run the harness again and use small tasks to clean up the failures until every test passes.
When a task fails repeatedly, I get better results by rewriting the task than by retrying the same instruction. Rewriting the task keeps the harness useful after I've made the larger change possible.
https://codykenb.github.io/learnings/