Comment 3 for bug 1240131

1) write a job that kills plainbox (IIRC there's one in stubbox or somewhere else)
2) run it and see what happens to plainbox
3) try stuff that misbehaves in other ways

One thing it boils down to is the exit status (not just exit code, exit status also has type of exit and more) we should get that data and use it.
The other thing is the pre-run/post-run session meta data update
Code that runs external programs is in plainbox.vendor.extcmd