Developer finds CI checks silently broken for months, catching nothing despite green status

A software developer audited 2,864 CI check runs across nine repositories and discovered that some checks had never functioned correctly despite always appearing to pass. Among the findings was a Vale linting rule designed to block em dashes from published content, which had silently failed to catch anything since it was first written due to a regex word-boundary bug. The rule appeared green on every run because both a broken check and a working one produce silence when no violations are triggered. The audit also revealed that failure rates were heavily clustered around migration and setup periods rather than spread evenly, making raw statistics misleading without contextual knowledge. The developer concluded that a passing CI status carries a hidden assumption — that the check is actually capable of catching what it was designed to catch.