Add subcomponent attribute to MCP instrumentation.

newrelic/hooks/adapter_mcp.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import logging
 
 from newrelic.api.function_trace import FunctionTrace
@@ -37,8 +38,10 @@ async def wrap_call_tool(wrapped, instance, args, kwargs):
     bound_args = bind_args(wrapped, args, kwargs)
     tool_name = bound_args.get("name") or "tool"
     function_trace_name = f"{func_name}/{tool_name}"
+    agentic_subcomponent_data = {"type": "APM-AI_TOOL", "name": tool_name}
 
-    with FunctionTrace(name=function_trace_name, group="Llm/tool/MCP", source=wrapped):
+    with FunctionTrace(name=function_trace_name, group="Llm/tool/MCP", source=wrapped) as ft:
+        ft._add_agent_attribute("subcomponent", json.dumps(agentic_subcomponent_data))
         return await wrapped(*args, **kwargs)
 
 

tests/adapter_mcp/test_mcp.py

@@ -19,6 +19,7 @@
 from mcp.server.fastmcp.tools import ToolManager
 from testing_support.ml_testing_utils import disabled_ai_monitoring_settings
 from testing_support.validators.validate_function_not_called import validate_function_not_called
+from testing_support.validators.validate_span_events import validate_span_events
 from testing_support.validators.validate_transaction_metrics import validate_transaction_metrics
 
 from newrelic.api.background_task import background_task
@@ -57,6 +58,7 @@ def echo_prompt(message: str):
     rollup_metrics=[("Llm/tool/MCP/mcp.client.session:ClientSession.call_tool/add_exclamation", 1)],
     background_task=True,
 )
+@validate_span_events(count=1, exact_agents={"subcomponent": '{"type": "APM-AI_TOOL", "name": "add_exclamation"}'})
 @background_task()
 def test_tool_tracing_via_client_session(loop, fastmcp_server):
     async def _test():
@@ -75,6 +77,7 @@ async def _test():
     rollup_metrics=[("Llm/tool/MCP/mcp.server.fastmcp.tools.tool_manager:ToolManager.call_tool/add_exclamation", 1)],
     background_task=True,
 )
+@validate_span_events(count=1, exact_agents={"subcomponent": '{"type": "APM-AI_TOOL", "name": "add_exclamation"}'})
 @background_task()
 def test_tool_tracing_via_tool_manager(loop):
     async def _test():