diff --git a/python/packages/core/agent_framework/_types.py b/python/packages/core/agent_framework/_types.py
index d2ed7de92c1..0d564310c4a 100644
--- a/python/packages/core/agent_framework/_types.py
+++ b/python/packages/core/agent_framework/_types.py
@@ -464,17 +464,20 @@ def add_usage_details(usage1: UsageDetails | None, usage2: UsageDetails | None)
             combined = add_usage_details(usage1, usage2)
             # Result: {'input_token_count': 8, 'output_token_count': 16}
     """
-    if usage1 is None:
-        return usage2 or UsageDetails()
-    if usage2 is None:
-        return usage1
+    u1 = usage1 or UsageDetails()
+    u2 = usage2 or UsageDetails()
 
     result = UsageDetails()
     # Combine all keys from both dictionaries
-    all_keys = set(usage1.keys()) | set(usage2.keys())
+    all_keys = set(u1.keys()) | set(u2.keys())
     for key in all_keys:
-        if not isinstance((val1 := usage1.get(key, 0)), (int | None)) or not isinstance(
-            (val2 := usage2.get(key, 0)), (int | None)
+        val1 = u1.get(key, 0)
+        val2 = u2.get(key, 0)
+        if (
+            isinstance(val1, bool)
+            or isinstance(val2, bool)
+            or not isinstance(val1, (int, type(None)))
+            or not isinstance(val2, (int, type(None)))
         ):
             logger.warning("Non `int` value found in usage details, skipping.")
             continue
diff --git a/python/packages/core/tests/core/test_types.py b/python/packages/core/tests/core/test_types.py
index df2f55efb63..a6797b30449 100644
--- a/python/packages/core/tests/core/test_types.py
+++ b/python/packages/core/tests/core/test_types.py
@@ -808,12 +808,43 @@ def test_usage_details_add_with_none_and_type_errors():
 
 
 def test_usage_details_add_skips_non_int():
-    u1 = cast(UsageDetails, {"input_token_count": 10, "other": "test"})
-    u2 = cast(UsageDetails, {"input_token_count": 10, "another": "test"})
+    u1 = cast(UsageDetails, {"input_token_count": 10, "other": "test", "flag": True})
+    u2 = cast(UsageDetails, {"input_token_count": 10, "another": "test", "flag": 5})
     u3 = add_usage_details(u1, u2)
     assert len(u3.keys()) == 1
     assert "input_token_count" in u3
     assert u3["input_token_count"] == 20
+    assert "flag" not in u3
+
+
+def test_usage_details_add_with_none_returns_copy():
+    u = UsageDetails(input_token_count=1)
+    v1 = add_usage_details(u, None)
+    v2 = add_usage_details(None, u)
+    assert v1 == u
+    assert v1 is not u
+    assert v2 == u
+    assert v2 is not u
+
+
+def test_usage_details_add_with_none_filters_booleans_and_non_ints():
+    payload = cast(UsageDetails, {"input_token_count": 5, "flag": True, "text": "skip_me"})
+    v1 = add_usage_details(payload, None)
+    v2 = add_usage_details(None, payload)
+    assert v1 == {"input_token_count": 5}
+    assert v1 is not payload
+    assert "flag" not in v1
+    assert "text" not in v1
+    assert v2 == {"input_token_count": 5}
+    assert v2 is not payload
+    assert "flag" not in v2
+    assert "text" not in v2
+
+
+def test_usage_details_add_both_none_returns_empty():
+    result = add_usage_details(None, None)
+    assert result == {}
+    assert isinstance(result, dict)
 
 
 # region UserInputRequest and Response