The DCO check fails any PR with an unsigned commit, and the rule appeared
nowhere in the repo — not AGENTS.md, CONTRIBUTING.md, README.md, or the Copilot
mirror. A hard merge gate that is invisible until it fails, whose remedy is a
history rewrite, is exactly what AGENTS.md exists to capture. It blocked #1978.
Added to the "When work is complete" list beside the other PR-hygiene gates,
weighted toward prevention over recitation: `git config format.signOff true`
once per clone beats remembering `-s`, because the failure is only discovered
after pushing. The repair path (`git rebase --signoff` + `--force-with-lease`)
carries the rebase caveat and the empty-remediation-commit alternative for when
you are not the sole author, plus a note that the signoff is a DCO assertion in
the author's own name and is never applied on someone else's behalf.
Mirrored into .github/copilot-instructions.md in the same PR, as AGENTS.md
requires for PR-hygiene rules — two lines next to `Closes #N` and the version
label, since the mirror is read on every review and is a distillation, not a
copy.
Not added to CONTRIBUTING.md: external contributors file issues rather than
PRs, so DCO never reaches them, and documenting it there would muddy that.
Closes#1979
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Signed-off-by: cliffhall <cliff@futurescale.com>
f4529df219