fix(harness): wrap async-only config tools for sync client execution (#2878)

* fix(harness): wrap async-only config tools for sync clients

* refactor(tools): share async tool sync wrapper

backend/packages/harness/deerflow/tools/sync.py

@@ -0,0 +1,36 @@
+"""Utilities for invoking async tools from synchronous agent paths."""
+
+import asyncio
+import atexit
+import concurrent.futures
+import logging
+from collections.abc import Callable
+from typing import Any
+
+logger = logging.getLogger(__name__)
+
+# Shared thread pool for sync tool invocation in async environments.
+_SYNC_TOOL_EXECUTOR = concurrent.futures.ThreadPoolExecutor(max_workers=10, thread_name_prefix="tool-sync")
+
+atexit.register(lambda: _SYNC_TOOL_EXECUTOR.shutdown(wait=False))
+
+
+def make_sync_tool_wrapper(coro: Callable[..., Any], tool_name: str) -> Callable[..., Any]:
+    """Build a synchronous wrapper for an asynchronous tool coroutine."""
+
+    def sync_wrapper(*args: Any, **kwargs: Any) -> Any:
+        try:
+            loop = asyncio.get_running_loop()
+        except RuntimeError:
+            loop = None
+
+        try:
+            if loop is not None and loop.is_running():
+                future = _SYNC_TOOL_EXECUTOR.submit(asyncio.run, coro(*args, **kwargs))
+                return future.result()
+            return asyncio.run(coro(*args, **kwargs))
+        except Exception as e:
+            logger.error("Error invoking tool %r via sync wrapper: %s", tool_name, e, exc_info=True)
+            raise
+
+    return sync_wrapper