{"url": "https://sub.xiliary.com/p/brendancodykenny/posts/83/stop-reimplementing-functionality-start-engineering-systems", "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": 83, "url": "https://sub.xiliary.com/p/brendancodykenny/posts/83/stop-reimplementing-functionality-start-engineering-systems", "kind": "published", "summary": "Stop reimplementing functionality. Start engineering systems.", "verbatim": null, "details": ["A lot of software repeats functionality already implemented thousands of times: date pickers, authentication, pagination, CRUD and workflows. Much of the expected behaviour is understood.", "AI has learned from those implementations. Software construction becomes selecting, translating and combining known solutions, not specifying every behaviour from scratch.", "We could reuse the tests too. HTTP has specifications and conformance suites. Generic behavioural contracts and property-based tests could check functionality across languages and frameworks.", "Combinations still need engineering. Correct components don't guarantee a correct system. Architecture, security and reliability can deteriorate while every feature passes its tests.", "Spend less effort rediscovering functionality and more on whole-system -ilities: maintainability, reliability, security, observability, scalability and recoverability."], "links": [], "tags": ["ai", "software-engineering", "testing", "verification"], "happened_on": null, "created": "2026-10-28T02:09:52.542229Z", "edited": "2026-10-28T02:13:01.550039Z", "source": null}}