{"armed": true} acquires the lease, enables and arms, and waits until every configured axis is ready. {"armed": false} runs Stop and Release.

If a latched execution fault can be cleared by a reset (recovery class reset_clears or reset_after_condition_clears), Arm resets it first, then re-acquires and arms, so one Arm recovers the machine. Faults that need a re-Home or a restart are left to their refusal. Errors: 400 dense_arm_invalid, 409 rt_core_arm_refused, 409 rt_core_arm_timeout, and rt-control reasons such as control_already_owned or not_ready.