Follow-up from #833. The tier-less apply-selections endpoint builds SlotSelection(**s) from body.slots; a missing key (e.g. capability) raises KeyError → 500. The only live caller sends well-formed dataclasses.asdict, but a defensive try/except KeyError → PickDefaultError(400) would harden the public route. src/hal0/api/routes/installer.py.
Follow-up from #833. The tier-less
apply-selectionsendpoint buildsSlotSelection(**s)frombody.slots; a missing key (e.g.capability) raises KeyError → 500. The only live caller sends well-formeddataclasses.asdict, but a defensivetry/except KeyError → PickDefaultError(400)would harden the public route.src/hal0/api/routes/installer.py.