diff --git a/github_webhook_updater.py b/github_webhook_updater.py
index 6c66d2d..99ea99e 100644
--- a/github_webhook_updater.py
+++ b/github_webhook_updater.py
@@ -48,7 +48,7 @@ def verify_signature(payload: bytes, signature: str) -> bool:
     return hmac.compare_digest(expected, signature)
 
 
-def pull_and_restart(changed_files: list[str]) -> tuple[bool, str]:
+def pull_and_restart(changed_files: list[str], before: str = '', after: str = '') -> tuple[bool, str]:
     """Pull latest changes from main and restart pm2 processes."""
     try:
         # Change to repo directory
@@ -79,6 +79,17 @@ def pull_and_restart(changed_files: list[str]) -> tuple[bool, str]:
 
         logger.info(f"Pull successful: {pull_result.stdout.strip()}")
 
+        # If the payload commits list was empty (e.g. GitHub PR merge), derive
+        # changed files from the before/after SHAs instead.
+        if not changed_files and before and after and before != '0' * 40:
+            diff_result = subprocess.run(
+                ['git', 'diff', '--name-only', before, after],
+                capture_output=True, text=True, timeout=15
+            )
+            if diff_result.returncode == 0:
+                changed_files = [f for f in diff_result.stdout.splitlines() if f]
+                logger.info(f"Derived changed files from git diff: {changed_files}")
+
         # Determine which processes to restart based on changed files
         processes_to_restart = []
 
@@ -242,6 +253,8 @@ def webhook():
     # Extract changed files from commits
     commits = payload.get('commits', [])
     pusher = payload.get('pusher', {}).get('name', 'unknown')
+    before = payload.get('before', '')
+    after = payload.get('after', '')
     logger.info(f"Push from {pusher} with {len(commits)} commit(s)")
 
     changed_files = []
@@ -253,7 +266,7 @@ def webhook():
     logger.info(f"Changed files: {changed_files}")
 
     # Pull and restart
-    success, message = pull_and_restart(changed_files)
+    success, message = pull_and_restart(changed_files, before, after)
 
     if success:
         logger.info(f"Webhook update successful: {message}")