diff --git a/packages/leann-core/src/leann/embedding_server_manager.py b/packages/leann-core/src/leann/embedding_server_manager.py
index 4358b00..2432325 100644
--- a/packages/leann-core/src/leann/embedding_server_manager.py
+++ b/packages/leann-core/src/leann/embedding_server_manager.py
@@ -185,6 +185,7 @@ class EmbeddingServerManager:
         self.backend_module_name = backend_module_name
         self.server_process: Optional[subprocess.Popen] = None
         self.server_port: Optional[int] = None
+        self._server_pid: Optional[int] = None  # Adopted server PID when not launched here
         self._atexit_registered = False
         # Also register a weakref finalizer to ensure cleanup when manager is GC'ed
         try:
@@ -221,6 +222,8 @@ class EmbeddingServerManager:
 
         if is_compatible:
             logger.info(f"Found compatible server on port {actual_port}")
+            # Adopt the existing server so we can clean it up on exit
+            self._adopt_existing_server(actual_port, model_name, passages_file)
             return True, actual_port
 
         # Start a new server
@@ -368,12 +371,36 @@ class EmbeddingServerManager:
 
     def stop_server(self):
         """Stops the embedding server process if it's running."""
-        if not self.server_process:
+        if not self.server_process and not self._server_pid:
             return
 
-        if self.server_process.poll() is not None:
+        # If we have an adopted PID and no Popen handle, try PID-based stop
+        if not self.server_process and self._server_pid:
+            try:
+                proc = psutil.Process(self._server_pid)
+                logger.info(f"Terminating adopted server process (PID: {self._server_pid})...")
+                proc.terminate()
+                try:
+                    proc.wait(timeout=5)
+                    logger.info(f"Adopted server process {self._server_pid} terminated gracefully.")
+                except psutil.TimeoutExpired:
+                    logger.warning(
+                        f"Adopted server process {self._server_pid} did not terminate within 5 seconds, force killing..."
+                    )
+                    proc.kill()
+                finally:
+                    self._server_pid = None
+                    self.server_port = None
+            except Exception as e:
+                logger.warning(f"Failed to terminate adopted server PID {self._server_pid}: {e}")
+                self._server_pid = None
+                self.server_port = None
+            return
+
+        if self.server_process and self.server_process.poll() is not None:
             # Process already terminated
             self.server_process = None
+            self.server_port = None
             return
 
         logger.info(
@@ -412,6 +439,7 @@ class EmbeddingServerManager:
             logger.warning(f"Error during process cleanup: {e}")
         finally:
             self.server_process = None
+            self.server_port = None
 
     def _finalize_process(self) -> None:
         """Best-effort cleanup used by weakref.finalize/atexit."""
@@ -420,6 +448,34 @@ class EmbeddingServerManager:
         except Exception:
             pass
 
+    def _adopt_existing_server(self, port: int, expected_model: str, passages_file: str) -> None:
+        """Adopt an existing compatible server so that we can stop it on exit.
+
+        This scans processes to find the PID listening on the given port that matches
+        our expected config, then records its PID and registers atexit cleanup.
+        """
+        try:
+            adopted_pid: Optional[int] = None
+            for proc in psutil.process_iter(["pid", "cmdline"]):
+                if not _is_process_listening_on_port(proc, port):
+                    continue
+                cmdline = proc.info.get("cmdline") or []
+                if _check_cmdline_matches_config(cmdline, port, expected_model, passages_file):
+                    adopted_pid = proc.info["pid"]
+                    break
+
+            if adopted_pid:
+                self._server_pid = adopted_pid
+                self.server_port = port
+                logger.info(f"Adopted existing embedding server PID {adopted_pid} on port {port}")
+                if not self._atexit_registered:
+                    atexit.register(self._finalize_process)
+                    self._atexit_registered = True
+            else:
+                logger.warning(f"Could not find PID to adopt for server on port {port}")
+        except Exception as e:
+            logger.warning(f"Failed to adopt existing server on port {port}: {e}")
+
     def _launch_server_process_colab(self, command: list, port: int) -> None:
         """Launch the server process with Colab-specific settings."""
         logger.info(f"Colab Command: {' '.join(command)}")