From 91b99b090d620a9e0f47248e1054702dc715bb67 Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 08:05:25 +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 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index f5881e7..e6c68cf 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -124,3 +124,20 @@ Footer: issue reference, e.g. Closes #123
 
 [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.

From 2614a6fce3ea399ec7842e9460e97f5c677285e7 Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 22:21:35 +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 | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index e6c68cf..f967733 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -138,6 +138,5 @@ unsigned pushes. Estate policy:
   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.
+  not just the result, so one unsigned commit blocks the merge. Re-sign the commits (`git cherry-pick -S`), then force-push the rewritten history to the existing PR branch.
   Rebase-merge replays commits unsigned and is disabled.