diff --git a/backend/packages/harness/deerflow/community/ddg_search/tools.py b/backend/packages/harness/deerflow/community/ddg_search/tools.py
index a91aec1975..7cbdbe79d0 100644
--- a/backend/packages/harness/deerflow/community/ddg_search/tools.py
+++ b/backend/packages/harness/deerflow/community/ddg_search/tools.py
@@ -33,10 +33,14 @@ WIKIPEDIA_LANGUAGE_ALIASES = {
 
 def _coerce_max_results(value: object) -> int:
     """Normalize config/parameter values before passing them to DDGS."""
-    try:
-        count = int(value)  # type: ignore[call-overload]
-    except (TypeError, ValueError, OverflowError):
+    if isinstance(value, bool) or (isinstance(value, float) and not value.is_integer()):
+        # int() accepts booleans and silently truncates a YAML value such as 3.5.
         count = 0
+    else:
+        try:
+            count = int(value)  # type: ignore[call-overload]
+        except (TypeError, ValueError, OverflowError):
+            count = 0
     if count <= 0:
         logger.warning("Invalid DDG Search max_results=%r; using default %s", value, DEFAULT_MAX_RESULTS)
         return DEFAULT_MAX_RESULTS
diff --git a/backend/tests/test_ddg_search_tools.py b/backend/tests/test_ddg_search_tools.py
index be37a9eedf..dca29aca89 100644
--- a/backend/tests/test_ddg_search_tools.py
+++ b/backend/tests/test_ddg_search_tools.py
@@ -22,6 +22,8 @@ from deerflow.community.ddg_search import tools
         pytest.param("$DDG_TEST_MAX_RESULTS", "abc", {"max_results": 2}, 5, True, id="invalid-env"),
         pytest.param("$DDG_TEST_MAX_RESULTS", "", {"max_results": 2}, 5, True, id="empty-env"),
         pytest.param("$DDG_TEST_MAX_RESULTS", "3.5", {"max_results": 2}, 5, True, id="fractional-env"),
+        pytest.param(3.5, "3", {"max_results": 2}, 5, True, id="fractional-config"),
+        pytest.param(True, "3", {"max_results": 2}, 5, True, id="boolean-config"),
         pytest.param("$DDG_TEST_MAX_RESULTS", "0", {"max_results": 2}, 5, True, id="zero-env"),
         pytest.param("$DDG_TEST_MAX_RESULTS", "-2", {"max_results": 2}, 5, True, id="negative-env"),
         pytest.param(0, "3", {}, 5, True, id="zero-config"),