diff --git a/python/packages/core/agent_framework/_tools.py b/python/packages/core/agent_framework/_tools.py
index 068830040ff..59aaf472803 100644
--- a/python/packages/core/agent_framework/_tools.py
+++ b/python/packages/core/agent_framework/_tools.py
@@ -47,6 +47,7 @@
 
 from opentelemetry import trace
 from opentelemetry.metrics import Histogram, NoOpHistogram
+from opentelemetry.util.types import AttributeValue
 from pydantic import BaseModel, Field, TypeAdapter, ValidationError, create_model
 from pydantic_core import to_jsonable_python
 
@@ -1231,8 +1232,13 @@ async def invoke(
             return parsed
 
         span_attributes = get_function_span_attributes(self, tool_call_id=tool_call_id)
-        metric_attributes = dict(span_attributes)
-        metric_attributes[OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME] = self.name
+        # Keep metric dimensions explicit so span-only attributes cannot flow into the histogram.
+        metric_attributes: dict[str, AttributeValue] = {
+            OtelAttr.OPERATION: OtelAttr.TOOL_EXECUTION_OPERATION,
+            OtelAttr.TOOL_NAME: self.name,
+            OtelAttr.TOOL_TYPE: "function",
+            OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME: self.name,
+        }
         # Filter out framework kwargs that are not JSON serializable.
         serializable_kwargs = {
             k: v
diff --git a/python/packages/core/tests/core/test_tools.py b/python/packages/core/tests/core/test_tools.py
index 8dd1da6f053..d7db2db4971 100644
--- a/python/packages/core/tests/core/test_tools.py
+++ b/python/packages/core/tests/core/test_tools.py
@@ -1037,11 +1037,12 @@ def telemetry_test_tool(expression: str) -> str:
     call_args = mock_histogram.record.call_args
     assert call_args[0][0] > 0  # duration should be positive
     attributes = call_args[1]["attributes"]
-    assert attributes[OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME] == "telemetry_test_tool"
-    assert attributes[OtelAttr.TOOL_CALL_ID] == "test_call_id"
-    assert OtelAttr.TOOL_ARGUMENTS not in attributes
-    assert OtelAttr.TOOL_RESULT not in attributes
-    assert expression not in attributes.values()
+    assert attributes == {
+        OtelAttr.OPERATION: OtelAttr.TOOL_EXECUTION_OPERATION,
+        OtelAttr.TOOL_NAME: "telemetry_test_tool",
+        OtelAttr.TOOL_TYPE: "function",
+        OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME: "telemetry_test_tool",
+    }
 
 
 @pytest.mark.parametrize("enable_sensitive_data", [False], indirect=True)
@@ -1085,8 +1086,12 @@ def telemetry_test_tool(x: int, y: int) -> int:
     call_args = mock_histogram.record.call_args
     assert call_args[0][0] > 0  # duration should be positive
     attributes = call_args[1]["attributes"]
-    assert attributes[OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME] == "telemetry_test_tool"
-    assert attributes[OtelAttr.TOOL_CALL_ID] == "test_call_id"
+    assert attributes == {
+        OtelAttr.OPERATION: OtelAttr.TOOL_EXECUTION_OPERATION,
+        OtelAttr.TOOL_NAME: "telemetry_test_tool",
+        OtelAttr.TOOL_TYPE: "function",
+        OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME: "telemetry_test_tool",
+    }
 
 
 @pytest.mark.parametrize("enable_sensitive_data", [True], indirect=True)
@@ -1228,9 +1233,13 @@ def exception_test_tool(x: int, y: int) -> int:
     mock_histogram.record.assert_called_once()
     call_args = mock_histogram.record.call_args
     attributes = call_args[1]["attributes"]
-    assert attributes[OtelAttr.ERROR_TYPE] == ValueError.__name__
-    assert OtelAttr.TOOL_ARGUMENTS not in attributes
-    assert OtelAttr.TOOL_RESULT not in attributes
+    assert attributes == {
+        OtelAttr.OPERATION: OtelAttr.TOOL_EXECUTION_OPERATION,
+        OtelAttr.TOOL_NAME: "exception_test_tool",
+        OtelAttr.TOOL_TYPE: "function",
+        OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME: "exception_test_tool",
+        OtelAttr.ERROR_TYPE: ValueError.__name__,
+    }
 
 
 async def test_tool_invoke_telemetry_async_function(span_exporter: InMemorySpanExporter):
@@ -1268,7 +1277,12 @@ async def async_telemetry_test(x: int, y: int) -> int:
     mock_histogram.record.assert_called_once()
     call_args = mock_histogram.record.call_args
     attributes = call_args[1]["attributes"]
-    assert attributes[OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME] == "async_telemetry_test"
+    assert attributes == {
+        OtelAttr.OPERATION: OtelAttr.TOOL_EXECUTION_OPERATION,
+        OtelAttr.TOOL_NAME: "async_telemetry_test",
+        OtelAttr.TOOL_TYPE: "function",
+        OtelAttr.MEASUREMENT_FUNCTION_TAG_NAME: "async_telemetry_test",
+    }
 
 
 async def test_tool_invoke_invalid_pydantic_args():