From 924bd2313cc644e9d3a414aa80a219e366535cd9 Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 13:31:11 +0100
Subject: [PATCH 1/2] docs: add Signed commits section to CONTRIBUTING

Owner ruling D218. See docs/SIGNING-POLICY.adoc in hyperpolymath/standards.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WRvDivYwLSeVCJUrfjic3f
---
 .github/CONTRIBUTING.md | 17 +++++++++++++++++
 CONTRIBUTING.adoc       | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 95e38e8..70c37ac 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -119,3 +119,20 @@ We follow [Conventional Commits](https://www.conventionalcommits.org/):
 [optional body]
 
 [optional footer]
+
+## Signed commits
+
+Every commit that reaches the default branch must be signed; a ruleset refuses
+unsigned pushes. Estate policy:
+[SIGNING-POLICY](https://github.com/hyperpolymath/standards/blob/main/docs/SIGNING-POLICY.adoc).
+
+- **People and interactive agents** sign with an SSH key registered on GitHub
+  as a *signing* key (`gpg.format=ssh`, `user.signingkey=<key>.pub`,
+  `commit.gpgsign=true`). The committer email must be verified on that account.
+- **Apps, bots and workflows** never `git push` local commits. They write
+  through the API (`createCommitOnBranch` or the estate `signed-push` action)
+  so that GitHub signs each commit.
+- Merge PRs with **squash**. The ruleset checks every commit on the PR branch,
+  not just the result, so one unsigned commit blocks the merge. Re-create such a
+  branch with signed commits (`git cherry-pick -S`) and open a new PR.
+  Rebase-merge replays commits unsigned and is disabled.
diff --git a/CONTRIBUTING.adoc b/CONTRIBUTING.adoc
index 858f44f..1510ca2 100644
--- a/CONTRIBUTING.adoc
+++ b/CONTRIBUTING.adoc
@@ -69,3 +69,20 @@ link:CODE_OF_CONDUCT.md[Code of Conduct].
 
 By contributing, you agree that your contributions will be licensed
 under the same license as the project (see LICENSE).
+
+== Signed commits
+
+Every commit that reaches the default branch must be signed; a ruleset refuses
+unsigned pushes. Estate policy:
+https://github.com/hyperpolymath/standards/blob/main/docs/SIGNING-POLICY.adoc[SIGNING-POLICY].
+
+* **People and interactive agents** sign with an SSH key registered on GitHub
+  as a *signing* key (`gpg.format=ssh`, `user.signingkey=<key>.pub`,
+  `commit.gpgsign=true`). The committer email must be verified on that account.
+* **Apps, bots and workflows** never `git push` local commits. They write
+  through the API (`createCommitOnBranch` or the estate `signed-push` action)
+  so that GitHub signs each commit.
+* Merge PRs with **squash**. The ruleset checks every commit on the PR branch,
+  not just the result, so one unsigned commit blocks the merge. Re-create such a
+  branch with signed commits (`git cherry-pick -S`) and open a new PR.
+  Rebase-merge replays commits unsigned and is disabled.

From 661ceb2be97c36646d7f415bc41a4cfd73563e0e Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 22:33:26 +0100
Subject: [PATCH 2/2] Update .github/CONTRIBUTING.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>
---
 .github/CONTRIBUTING.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 70c37ac..610071a 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -134,5 +134,7 @@ unsigned pushes. Estate policy:
   so that GitHub signs each commit.
 - Merge PRs with **squash**. The ruleset checks every commit on the PR branch,
   not just the result, so one unsigned commit blocks the merge. Re-create such a
-  branch with signed commits (`git cherry-pick -S`) and open a new PR.
+  branch with signed commits (`git cherry-pick -S`) and force-push the updated
+  branch. Keep the existing PR; open a new PR only if branch rules prevent
+  updating the branch.
   Rebase-merge replays commits unsigned and is disabled.