Claude Code: Cain is showing RUNTIME_ERROR status. I need you to:

scripts/sync_hf.py

@@ -186,6 +186,7 @@ class OpenClawFullSync:
         self.enabled = False
         self.dataset_exists = False
         self.api = None
+        self._last_upload_hash = None  # Track last uploaded state
 
         if not HF_TOKEN:
             print("[SYNC] WARNING: HF_TOKEN not set. Persistence disabled.")
@@ -199,6 +200,44 @@ class OpenClawFullSync:
         self.api = HfApi(token=HF_TOKEN)
         self.dataset_exists = self._ensure_repo_exists()
 
+    def _compute_files_hash(self):
+        """Compute a hash of file paths and mtimes to detect changes efficiently."""
+        import hashlib
+        file_hash = hashlib.sha256()
+
+        # Get all files, sorted for consistent hashing
+        files_list = []
+        for root, dirs, files in os.walk(OPENCLAW_HOME):
+            for fn in files:
+                # Skip ignored patterns
+                if any(fn.endswith(p.strip('*')) for p in ['*.log', '*.lock', '*.tmp', '*.pid']):
+                    continue
+                if '__pycache__' in root:
+                    continue
+                fp = os.path.join(root, fn)
+                files_list.append(fp)
+
+        # Hash based on file paths and modification times (much faster than reading content)
+        for fp in sorted(files_list):
+            try:
+                stat = os.stat(fp)
+                # Include path, size, and mtime in hash
+                file_hash.update(fp.encode())
+                file_hash.update(str(stat.st_size).encode())
+                file_hash.update(str(stat.st_mtime).encode())
+            except Exception:
+                # File might be locked or inaccessible - skip it
+                pass
+
+        return file_hash.hexdigest()
+
+    def _has_changes(self):
+        """Check if any files have changed since last upload."""
+        current_hash = self._compute_files_hash()
+        if self._last_upload_hash is None:
+            return True
+        return current_hash != self._last_upload_hash
+
     # ── Repo management ────────────────────────────────────────────────
 
     def _ensure_repo_exists(self):
@@ -284,6 +323,11 @@ class OpenClawFullSync:
         self._patch_config()
         self._debug_list_files()
 
+        # Initialize hash after restore to avoid unnecessary first upload
+        if self.enabled and OPENCLAW_HOME.exists():
+            self._last_upload_hash = self._compute_files_hash()
+            print(f"[SYNC] Initialized change detection hash")
+
     # ── Save (periodic + shutdown) ─────────────────────────────────────
 
     def save_to_repo(self):
@@ -299,6 +343,11 @@ class OpenClawFullSync:
             print(f"[SYNC] Dataset {HF_REPO_ID} unavailable - skipping save")
             return
 
+        # Check for changes before attempting upload
+        if not self._has_changes():
+            print(f"[SYNC] No changes detected since last sync. Skipping upload.")
+            return
+
         print(f"[SYNC] ▶ Uploading ~/.openclaw → dataset {HF_REPO_ID}/{DATASET_PATH}/ ...")
 
         try:
@@ -334,6 +383,9 @@ class OpenClawFullSync:
             )
             print(f"[SYNC] ✓ Upload completed at {datetime.now().isoformat()}")
 
+            # Update hash after successful upload
+            self._last_upload_hash = self._compute_files_hash()
+
             # Verify (summary only)
             try:
                 files = self.api.list_repo_files(repo_id=HF_REPO_ID, repo_type="dataset")
@@ -343,6 +395,12 @@ class OpenClawFullSync:
                 pass
 
         except Exception as e:
+            error_msg = str(e)
+            # Handle empty commit gracefully - this is not an error
+            if "No files have been modified" in error_msg or "empty commit" in error_msg.lower():
+                print(f"[SYNC] No changes to commit (already in sync)")
+                self._last_upload_hash = self._compute_files_hash()
+                return
             print(f"[SYNC] ✗ Upload failed: {e}")
             traceback.print_exc()