Annotate root spans with operation name

Author: nagkumar91

instrumentation-genai/opentelemetry-instrumentation-openai-agents-v2/src/opentelemetry/instrumentation/openai_agents/span_processor.py

@@ -1273,6 +1273,7 @@ def on_trace_start(self, trace: Trace) -> None:
             attributes = {
                 GEN_AI_PROVIDER_NAME: self.system_name,
                 GEN_AI_SYSTEM_KEY: self.system_name,
+                GEN_AI_OPERATION_NAME: GenAIOperationName.INVOKE_AGENT,
             }
             # Legacy emission removed
 

instrumentation-genai/opentelemetry-instrumentation-openai-agents-v2/tests/test_z_span_processor_unit.py

@@ -499,6 +499,11 @@ def test_span_lifecycle_and_shutdown(processor_setup):
         statuses["linger"].status_code is StatusCode.ERROR
         and statuses["linger"].description == "Application shutdown"
     )
+    workflow_span = next(span for span in finished if span.name == "workflow")
+    assert (
+        workflow_span.attributes[sp.GEN_AI_OPERATION_NAME]
+        == sp.GenAIOperationName.INVOKE_AGENT
+    )
 
 
 def test_chat_span_renamed_with_model(processor_setup):