The message that is logged is based on the information provided by the specific event hook (i.e. switchyard event listener). So in the case of the response, at the point the event listener is triggered, the exchange contains a Java object. This is then transformed as part of the binding when returning the response to the client.

One thing you could try, is to define a transformer in the ip.json for the returned type (my.packages.OperationOutput) using an mvel expression that invokes a utility (that you would need to provide) to transform the message content into XML. If the utility classes are packages in the same war as the ip.json, then it should work - although I've not actually tried this out.

The switchyard listener mechanism used in rtgov is a separate component (which can be undeployed), so if you find a more appropriate interceptor point for your needs, then you could write your own listener and create the same types of rtgov activity events.

The code used by RTGov to listener for switchyard events and report them as activity events is here: https://github.com/Governance/rtgov/tree/master/integration/switchyard/src/main/java/org/overlord/rtgov/internal/switchyard

That is why in my previous response I said that you should replace the current overlord-rtgov-switchyard.war with your own integration with switchyard - then you are in control of when the activity unit starts and ends.

As mentioned before, simply take a copy of ALL of the code in the overlord-rtgov-switchyard.war module (rtgov/integration/switchyard at master · Governance/rtgov · GitHub) and build your own version of that war making whatever code changes you want.