Developer's Own CI Rule Flags Their Explanation of That Same Rule on Day One

A developer building a documentation linter for their project discovered that 47 documents already violated their own 45-line rule, including a 1,203-line offender, before CI was even active. Rather than creating an ignore list or fixing all violations upfront — both seen as traps that delay enforcement or freeze progress — they designed the checker to flag only files that grew longer in a given pull request, not pre-existing violations. This approach uses git's merge-base comparison to avoid creating a second source of truth and to prevent penalizing contributors who make small, unrelated fixes. The rules file itself had to be split into eight separate documents to comply with the very standard it defined. On the first real run, CI flagged the developer's own file mid-edit — the doc explaining the new growth-detection rule had just crossed 46 lines.