Recover from missing DCO sign-off on commits. Handles the single-commit amend, older-commit recovery via interactive rebase or cherry-pick, and explains the Probot DCO check that blocks PRs without sign-off. Use when a PR fails the DCO check, when a commit needs a Signed-off-by trailer added retroactively, or when sign-off was forgotten during rebase / cherry-pick / amend.
73
91%
Does it follow best practices?
Run evals on this skill
Adds up to 20 points to the overall score
View guide
Passed
No findings from the security scan
All commits in this repo must carry a Signed-off-by: trailer (Developer Certificate of Origin). The Probot DCO check on PRs blocks merge until every commit is signed.
The standard way to add it is with --signoff at commit time. This skill handles the cases where that was missed.
git commit --amend --signoff -S --no-edit
git push --force-with-lease--force-with-lease is preferred over plain --force — it refuses if someone else has pushed to the branch since you last fetched.
Find the commit hash of the oldest unsigned commit:
git log --pretty='%h %s %(trailers:key=Signed-off-by,valueonly)' origin/main..HEAD
# Any line with an empty trailing field is unsignedThen interactively rebase from one commit before that:
git rebase -i <parent-of-unsigned-commit>
# In the editor, change `pick` to `edit` for each unsigned commit
# Save and exit; the rebase stops at each `edit` line so you can amendFor each commit in the rebase, replace it with a signed version:
git commit --amend --signoff -S --no-edit
git rebase --continueWhen done, force-push:
git push --force-with-leaseCherry-pick with sign-off baked in:
git cherry-pick --signoff <sha>If you already cherry-picked without it, fall back to Case 1 or Case 2 above.
Before pushing, verify every commit ahead of origin/main has both DCO and GPG:
git log --format='%G? %(trailers:key=Signed-off-by,valueonly,separator=%x20) %h %s' origin/main..HEADEach line must start with G or U (good GPG signature) AND carry a non-empty Signed-off-by value before the SHA. Codes N / B / E need investigation. See .claude/rules/commit-workflow.md for the canonical signing policy.
The check passes when every commit message includes a Signed-off-by: Name <email> trailer matching the commit author's email. The --signoff (or -s) flag adds this trailer automatically using your user.name and user.email git config.
A failing DCO check on a PR will show a "Details" link explaining which commits are missing sign-off.
7038855
If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.