diff --git a/.github/workflows/dependabot-automerge.yml b/.github/workflows/dependabot-automerge.yml
index 047758eb..f750d57d 100644
--- a/.github/workflows/dependabot-automerge.yml
+++ b/.github/workflows/dependabot-automerge.yml
@@ -1,7 +1,7 @@
 name: Dependabot auto-merge
 
 on:
-  pull_request:
+  pull_request_target:
     branches:
       - main
 
@@ -20,16 +20,19 @@ jobs:
         with:
           github-token: '${{ secrets.GITHUB_TOKEN }}'
 
-      - name: Enable auto-merge for patch, minor, and indirect updates
+      - name: Generate app token
+        if: steps.metadata.outputs.update-type == 'version-update:semver-patch' || steps.metadata.outputs.update-type == 'version-update:semver-minor' || steps.metadata.outputs.dependency-type == 'indirect'
+        id: app-token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.APP_ID }}
+          private-key: ${{ secrets.APP_PRIVATE_KEY }}
+
+      - name: Approve and auto-merge
         if: steps.metadata.outputs.update-type == 'version-update:semver-patch' || steps.metadata.outputs.update-type == 'version-update:semver-minor' || steps.metadata.outputs.dependency-type == 'indirect'
         run: |
-          # Enable auto-merge to handle future check completions
-          gh pr merge --auto --squash "$PR_URL"
-          # If all required checks are already passing, merge immediately since
-          # auto-merge only triggers on subsequent check completions, not existing ones
-          if [ "$(gh pr view "$PR_URL" --json mergeable --jq '.mergeable')" = "true" ]; then
-            gh pr merge --squash "$PR_URL"
-          fi
+          gh pr review --approve "$PR_URL"
+          gh pr merge --squash --admin "$PR_URL"
         env:
           PR_URL: ${{ github.event.pull_request.html_url }}
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_TOKEN: ${{ steps.app-token.outputs.token }}
diff --git a/scripts/setup-dependabot-app.sh b/scripts/setup-dependabot-app.sh
new file mode 100755
index 00000000..0018abca
--- /dev/null
+++ b/scripts/setup-dependabot-app.sh
@@ -0,0 +1,128 @@
+#!/usr/bin/env bash
+# setup-dependabot-app.sh
+#
+# Configures a repository to use the org-wide "dependabot-automerge-petry"
+# GitHub App for Dependabot auto-merge. The app must already be created and
+# installed on the org (see PR #71 for context).
+#
+# What this script does:
+#   1. Stores APP_ID and APP_PRIVATE_KEY as repo secrets
+#   2. Adds the app to the repo's ruleset bypass list (if a matching ruleset exists)
+#   3. Copies the dependabot-automerge workflow into the repo
+#
+# Prerequisites: gh (authenticated), python3
+# Usage:
+#   bash scripts/setup-dependabot-app.sh                          # current repo
+#   bash scripts/setup-dependabot-app.sh owner/other-repo         # specific repo
+#   APP_PRIVATE_KEY_FILE=path/to/key.pem bash scripts/setup-dependabot-app.sh
+
+set -euo pipefail
+
+# ── Configuration ─────────────────────────────────────────────────────────────
+APP_ID="${APP_ID:-3167543}"
+APP_NAME="dependabot-automerge-petry"
+RULESET_NAME="${RULESET_NAME:-protect-branches}"
+
+# Target repo: first arg, or detect from current directory
+if [ -n "${1:-}" ]; then
+  REPO="$1"
+else
+  REPO="$(gh repo view --json nameWithOwner -q .nameWithOwner 2>/dev/null || true)"
+  if [ -z "$REPO" ]; then
+    echo "Usage: $0 [owner/repo]"
+    exit 1
+  fi
+fi
+
+echo "=== Dependabot Auto-Merge Setup ==="
+echo "  App:  $APP_NAME (ID: $APP_ID)"
+echo "  Repo: $REPO"
+echo ""
+
+# ── Preflight ─────────────────────────────────────────────────────────────────
+for cmd in gh python3; do
+  command -v "$cmd" >/dev/null || { echo "Error: $cmd is required"; exit 1; }
+done
+gh auth status >/dev/null 2>&1 || { echo "Error: gh not authenticated"; exit 1; }
+
+# ── Step 1: Store secrets ─────────────────────────────────────────────────────
+echo "Step 1/3: Storing secrets..."
+
+# Locate private key
+KEY_FILE="${APP_PRIVATE_KEY_FILE:-}"
+if [ -z "$KEY_FILE" ]; then
+  # Search common locations
+  for candidate in \
+    "$HOME/dependabot-automerge-petry.pem" \
+    "$HOME/dependabot-google-app-scripts"*.pem \
+    "$HOME/.ssh/dependabot-automerge-petry.pem"; do
+    if [ -f "$candidate" ]; then
+      KEY_FILE="$candidate"
+      break
+    fi
+  done
+fi
+
+if [ -z "$KEY_FILE" ] || [ ! -f "$KEY_FILE" ]; then
+  echo "Error: Private key file not found."
+  echo "Set APP_PRIVATE_KEY_FILE or place the .pem file in your home directory."
+  exit 1
+fi
+
+echo "$APP_ID" | gh secret set APP_ID --repo "$REPO"
+echo "  ✓ APP_ID"
+
+gh secret set APP_PRIVATE_KEY --repo "$REPO" < "$KEY_FILE"
+echo "  ✓ APP_PRIVATE_KEY (from $KEY_FILE)"
+
+# ── Step 2: Add app to ruleset bypass list ────────────────────────────────────
+echo ""
+echo "Step 2/3: Updating ruleset bypass list..."
+
+RULESET_ID=$(gh api "repos/$REPO/rulesets" -q ".[] | select(.name == \"$RULESET_NAME\") | .id" 2>/dev/null || echo "")
+
+if [ -z "$RULESET_ID" ]; then
+  echo "  ⏭ No '$RULESET_NAME' ruleset found — skipping"
+else
+  CURRENT=$(gh api "repos/$REPO/rulesets/$RULESET_ID")
+
+  UPDATED=$(echo "$CURRENT" | python3 -c "
+import sys, json
+r = json.load(sys.stdin)
+app_id = $APP_ID
+bypass = r.get('bypass_actors', [])
+if not any(a.get('actor_id') == app_id and a.get('actor_type') == 'Integration' for a in bypass):
+    bypass.append({'actor_id': app_id, 'actor_type': 'Integration', 'bypass_mode': 'always'})
+    print(json.dumps({
+        'name': r['name'], 'target': r.get('target', 'branch'),
+        'enforcement': r['enforcement'], 'conditions': r.get('conditions', {}),
+        'rules': r.get('rules', []), 'bypass_actors': bypass
+    }))
+else:
+    print('ALREADY_PRESENT')
+")
+
+  if [ "$UPDATED" = "ALREADY_PRESENT" ]; then
+    echo "  ✓ App already in bypass list"
+  else
+    echo "$UPDATED" | gh api "repos/$REPO/rulesets/$RULESET_ID" --method PUT --input - >/dev/null
+    echo "  ✓ App added to '$RULESET_NAME' bypass list"
+  fi
+fi
+
+# ── Step 3: Ensure workflow exists ────────────────────────────────────────────
+echo ""
+echo "Step 3/3: Checking workflow..."
+
+WORKFLOW_EXISTS=$(gh api "repos/$REPO/contents/.github/workflows/dependabot-automerge.yml" --jq '.name' 2>/dev/null || echo "")
+
+if [ -n "$WORKFLOW_EXISTS" ]; then
+  echo "  ✓ dependabot-automerge.yml already exists"
+else
+  echo "  ⚠ dependabot-automerge.yml not found in $REPO"
+  echo "    Copy .github/workflows/dependabot-automerge.yml into the repo."
+fi
+
+# ── Done ──────────────────────────────────────────────────────────────────────
+echo ""
+echo "=== Setup complete for $REPO ==="