based on the thread you can find here https://help.workspace.ibm.com/hc/en-us/community/posts/115007131888-App-messages-are-not-equivilent-to-person-messages messages created by an App do not contain any content because the text is contained in Annotation. This is a work by design as far as I know.
The Action Fullfillment seems to be activated from the content of a message..is it right?
If so,this means that a message posted by an app cannot be used by i.e. Watson Assistant or any other app which is listening on a space.
If I have a monitoring tool which writes an alert in a space,how can I take advantage of the Action Fullfillment on that alert? (i.e. I would like to search the alert message in an external Knowledge Base...)
Is my understanding correct? Any suggestion?
Thanks in advance,Marina