{"url": "https://sub.xiliary.com/p/brendancodykenny/posts/70/learnings-from-harness-engineering", "author": {"handle": "brendancodykenny", "name": "Brendan Cody-Kenny", "headline": "Technical Due Diligence for Software M&A", "url": "https://sub.xiliary.com/p/brendancodykenny", "photo": "https://sub.xiliary.com/p/brendancodykenny/photo?v=1790520774"}, "post": {"id": 70, "url": "https://sub.xiliary.com/p/brendancodykenny/posts/70/learnings-from-harness-engineering", "kind": "offering", "summary": "Learnings from harness engineering", "verbatim": null, "details": ["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."], "links": ["https://codykenb.github.io/learnings/"], "tags": ["coding-agents", "harness-engineering", "local-optima", "sbse"], "happened_on": null, "created": "2026-10-15T13:03:43.683234Z", "edited": "2026-10-15T13:05:12.919394Z", "source": null}}