Fix MCP server startup for Claude Code compatibility

- Suppress stderr output (Claude Code rejects servers with stderr)
- Make SyncEngine.start() non-blocking (blocking sync caused 15s+ timeout)
- Skip Content-Length header lines gracefully (NDJSON transport)
- Silently ignore malformed JSON lines instead of sending error responses

src/claude_memory/mcp_server.py

@@ -600,19 +600,11 @@ class MemoryServer:
         try:
             for line in sys.stdin:
                 line = line.strip()
-                if not line:
+                if not line or line.startswith("Content-Length:"):
                     continue
                 try:
                     message = json.loads(line)
-                except json.JSONDecodeError as e:
+                except json.JSONDecodeError:
-                    print(
-                        json.dumps({
-                            "jsonrpc": "2.0",
-                            "id": None,
-                            "error": {"code": -32700, "message": f"Parse error: {e}"},
-                        }),
-                        flush=True,
-                    )
                     continue
                 response = self.process_message(message)
                 if response is not None:
@@ -623,6 +615,11 @@ class MemoryServer:
 
 
 def main() -> None:
+    # Suppress all stderr output — MCP clients (e.g. Claude Code) may treat
+    # any stderr as a fatal error and refuse to load the server.
+    sys.stderr = open(os.devnull, "w")
+    logging.disable(logging.CRITICAL)
+
     server = MemoryServer()
     server.run()
 

src/claude_memory/sync.py

@@ -87,14 +87,7 @@ class SyncEngine:
         return self._last_sync_success
 
     def start(self) -> None:
-        """Run initial sync (blocking), then start background thread."""
+        """Start background sync thread (non-blocking)."""
-        try:
-            self._sync_once()
-            self._last_sync_success = True
-        except Exception:
-            logger.warning("Initial sync failed, starting in offline mode")
-            self._last_sync_success = False
-
         self._thread = threading.Thread(target=self._sync_loop, daemon=True)
         self._thread.start()