ran into this while having an agent drive a sim headless (lock screen captures for live activity stuff).
at some point the helper's HID injection just died. serve-sim button lock, tap, gesture — all of them kept exiting 0 but nothing was landing on the device. --list was still reporting running: true the whole time. so from a script/agent's perspective everything looks healthy while literally no input works.
for a human this is a minor annoyance because you'd notice the screen not changing. for an agent it's brutal — it trusts the exit code, so it just keeps going and burns a ton of time debugging the wrong layer (we restarted springboard, tried notifyutil, eventually did a full sim reboot before figuring out it was the helper).
couldn't pin down the exact trigger. it survived normal use for hours and then died after a stretch of heavy lock/unlock cycling + a simctl shutdown/boot of the device. restarting the helper (--kill + fresh start) didn't always bring input back either, which was the confusing part.
what would fix the pain isn't even preventing the breakage, it's making it loud:
- non-zero exit when the HID send doesn't actually land (or at least when the injector knows its connection is gone)
- some health signal in
--list beyond running true/false, like hid: ok/stale
happy to provide more details, we hit this on macOS 26 (tahoe) with xcode 26 sims, serve-sim 0.1.45.
ran into this while having an agent drive a sim headless (lock screen captures for live activity stuff).
at some point the helper's HID injection just died.
serve-sim button lock,tap,gesture— all of them kept exiting 0 but nothing was landing on the device.--listwas still reportingrunning: truethe whole time. so from a script/agent's perspective everything looks healthy while literally no input works.for a human this is a minor annoyance because you'd notice the screen not changing. for an agent it's brutal — it trusts the exit code, so it just keeps going and burns a ton of time debugging the wrong layer (we restarted springboard, tried notifyutil, eventually did a full sim reboot before figuring out it was the helper).
couldn't pin down the exact trigger. it survived normal use for hours and then died after a stretch of heavy lock/unlock cycling + a
simctl shutdown/bootof the device. restarting the helper (--kill+ fresh start) didn't always bring input back either, which was the confusing part.what would fix the pain isn't even preventing the breakage, it's making it loud:
--listbeyond running true/false, like hid: ok/stalehappy to provide more details, we hit this on macOS 26 (tahoe) with xcode 26 sims, serve-sim 0.1.45.