Shell job control does not survive an agent's stateless tool calls. Use the harness background primitive when there is one; otherwise detach the process, log to a unique file, and persist the PID and exit code to disk so a later call can poll them.
A JVM-wide singleton cache and default JVM reuse in Surefire hid an order-dependent test bug behind a fully green suite, until one flag flipped the run order and made it fail on demand.
Two regressions that only surfaced after deploying a javax-to-jakarta, EAP7-to-EAP8 migration to a real runtime, and why a free smoke test would have caught both.