I wanted to check this for clarity before we commit to using the API within a workflow, the /consult/external endpoint allows you to kick off a consult call from a data action. Typically, we would expect the consult to require user context (not complaining here), but just want to make sure this wasn't a bug introduced and we will suddenly lose this functionality.
I would strongly recommend opening a case with Care to get a formal commitment for this behavior. That seems suspect since, as you noted, conversations endpoints typically do require a user context. I would expect this one to follow that pattern. We don't document if a user context or client credentials are allowed/prohibited for API resources, so it's technically an undocumented feature, so it's technically subject to change without notice. Care will be able to open a servops ticket to get formal confirmation on this behavior from the dev team, which will constitute a commitment to that behavior. Or it will result in a bug report, also giving you an answer.