fix(community): fall back to the default SearXNG max_results on an unparseable value (#5821)

* fix(community): fall back to the default SearXNG max_results on an unparseable value

A blank `max_results:` in config.yaml loads as None, and int(None) then fails inside web_search_tool's try block, so every SearXNG search returns an error payload instead of results. Coerce like the sibling providers do: warn and keep the documented default.

* test(community): cover SearXNG max_results that cannot be parsed

backend/packages/harness/deerflow/community/searxng/tools.py

@@ -41,7 +41,17 @@ async def web_search_tool(query: str, time_range: SearchTimeRange | None = None)
         max_results = 5
         if cfg is not None:
             raw = cfg.get("max_results", max_results)
-            max_results = int(raw) if not isinstance(raw, int) else raw
+            if isinstance(raw, int):
+                max_results = raw
+            else:
+                try:
+                    max_results = int(raw)
+                except (TypeError, ValueError):
+                    logger.warning(
+                        "Invalid SearXNG max_results=%r; using default %s",
+                        raw,
+                        max_results,
+                    )
 
         client = _get_searxng_client()
         search_kwargs: dict[str, object] = {"max_results": max_results}

backend/tests/test_searxng_client.py

@@ -269,6 +269,24 @@ class TestSearxngTools:
         call_kwargs = mock_client.search.call_args.kwargs
         assert call_kwargs["max_results"] == 3
 
+    @patch("deerflow.community.searxng.tools._get_searxng_client")
+    async def test_web_search_tool_unparseable_max_results_uses_default(self, mock_get_client):
+        """A max_results the config cannot give as a number falls back to the default."""
+        mock_client = MagicMock()
+        mock_client.search = AsyncMock(return_value=[])
+        mock_get_client.return_value = mock_client
+
+        # ``max_results:`` left blank in config.yaml loads as None; a word is a
+        # typo an operator can just as easily make. Neither is a reason to stop
+        # searching -- every sibling provider falls back to the default.
+        for raw in (None, "many"):
+            with patch("deerflow.community.searxng.tools._get_tool_config", return_value={"max_results": raw}):
+                result = await tools.web_search_tool.ainvoke("test query")
+
+            assert "error" not in json.loads(result), f"max_results={raw!r} failed the whole call"
+            mock_client.search.assert_called_once_with("test query", max_results=5)
+            mock_client.search.reset_mock()
+
     @patch("deerflow.community.searxng.tools._get_searxng_client")
     async def test_web_search_tool_forwards_time_range(self, mock_get_client):
         """web_search_tool forwards the requested relative time range."""