diff --git a/.github/workflows/governance-drift.yml b/.github/workflows/governance-drift.yml
new file mode 100644
index 0000000..f19c4c7
--- /dev/null
+++ b/.github/workflows/governance-drift.yml
@@ -0,0 +1,21 @@
+name: Governance drift
+
+on:
+  schedule:
+    - cron: '23 3 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  drift:
+    name: drift
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Compare the twin repositories
+        run: sh pr-governance/scripts/check-twin-drift.sh
diff --git a/VERSION b/VERSION
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/VERSION
@@ -0,0 +1 @@
+3
diff --git a/pr-governance/README.md b/pr-governance/README.md
index fea5198..025ed62 100644
--- a/pr-governance/README.md
+++ b/pr-governance/README.md
@@ -23,6 +23,10 @@ A pull request may merge when all of these hold:
 Branch protection, not this action, is the merge constraint. The action only
 publishes evidence; it cannot merge, label, or write repository contents.
 
+The gate applies to repositories that build, deploy or run code. A repository
+that only publishes a static site through a `pages` workflow keeps that
+deployment workflow and is exempt from the gate.
+
 ## Risk tiers
 
 | Tier | Typical paths | Requirement |
@@ -124,6 +128,15 @@ a fresh review instead of silently reusing one.
 ## Private repositories
 
 GitHub Free does not provide branch protection or secret scanning for private
-repositories, and hosted Actions may be billing-blocked. Use the local track:
-the same policy file, a pre-push hook and `scripts/local` commands recording
-the same receipt and scan results locally. See `docs/private-repositories.md`.
+repositories, and hosted Actions may be billing-blocked. Private repositories
+use a local enforcement track instead: Git hooks that reject staged credentials,
+unconventional commit headers, direct pushes to a protected branch, and
+non-fast-forward pushes, plus an audit over the tracked tree.
+
+
+## Twin repositories
+
+`pr-governance/` is byte-identical in `Pigbibi/governance`, `GdeiAssistant/.github`
+and `QuantStrategyLab/.github`; `VERSION` names the shared revision. Each
+repository runs `scripts/check-twin-drift.sh` weekly and on demand. A change to
+any shared file is applied to all three before the drift check can pass.
diff --git a/pr-governance/scripts/check-twin-drift.sh b/pr-governance/scripts/check-twin-drift.sh
new file mode 100755
index 0000000..d892b20
--- /dev/null
+++ b/pr-governance/scripts/check-twin-drift.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+# Compare the shared governance content across the three twin repositories.
+set -eu
+
+REPOS="Pigbibi/governance GdeiAssistant/.github QuantStrategyLab/.github"
+base=$(cd "$(dirname "$0")/../.." && pwd)
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+status=0
+
+for repo in $REPOS; do
+  slug=$(printf '%s' "$repo" | tr '/' '_')
+  mkdir -p "$tmp/$slug"
+  archive="$tmp/$slug.tar.gz"
+  if ! curl --fail --silent --show-error --location --retry 2 \
+      "https://codeload.github.com/$repo/tar.gz/refs/heads/main" --output "$archive"; then
+    echo "cannot download $repo" >&2
+    status=1
+    continue
+  fi
+  if ! tar -xzf "$archive" -C "$tmp/$slug" --strip-components=1; then
+    echo "cannot extract $repo" >&2
+    status=1
+    continue
+  fi
+  for path in pr-governance VERSION; do
+    if ! diff -ru -x '__pycache__' "$base/$path" "$tmp/$slug/$path"; then
+      echo "drift: $path differs from $repo" >&2
+      status=1
+    fi
+  done
+done
+
+exit $status