Small mechanical guardrails so drift, stranded files, and branch litter fail loudly instead of accumulating — distilled from Random AI Prompt’s large-restructure experience, where each of these bit repeatedly until a guard made it self-catching. The canonical copy is in the repository at hub/standards/repo-hygiene.md, with portable zero-dependency starter scripts under hub/templates/.

The rules

• Doc-drift gate — a broken-link checker. A script walks every tracked .md and fails the build on any relative link whose target doesn’t exist. Wired into the test gate and CI, so a rename that leaves a dangling link turns red before it merges.
• Uncommitted-file guard. A script fails on any untracked, non-ignored file — the exact signature of “someone wrote a doc and never committed it”. Run before finishing a session.
• Nothing useful is ever left uncommitted. Notes are committed as you go; the changelog entry rides in the same commit as its change; every process report gets committed.
• Rename / move / remove → sweep the docs in the same change. The link gate catches dangling links; git grep the old name catches prose. Fix current-state docs; leave dated history intact.
• Delete spent branches — with one non-obvious guard. Enable delete_branch_on_merge, but protect the long-lived work branch so the first dev → main release PR doesn’t auto-delete dev.

The policy half of doc drift lives in docs-lifecycle; this standard is the mechanical enforcement.