Spanda

Health Checks

Spanda provides unified health monitoring for robots, devices, sensors, actuators, agents, fleets, and swarms.

Health statuses

Healthy, Degraded, Warning, Critical, Failed, Unknown, Offline, Unsafe

Robot health check

health_check RoverHealth for robot Rover {
    check battery.level > 20%;
    check gps.status == Healthy;
    check wheels.status == Healthy;
    check emergency_stop.available == true;
}

Sensor / actuator health

health_check GPSHealth for sensor gps {
    check gps.fix_available == true;
    check gps.accuracy <= 3 m;
}

health_check WheelsHealth for actuator wheels {
    check wheels.temperature < 70 C;
    check wheels.emergency_stop_supported == true;
}

Fleet / swarm health

health_check FleetHealth for fleet WarehouseFleet {
    require at_least 80% robots Healthy;
    require no robot Unsafe;
    check rover.status == Healthy;
}

Fleet require clauses are parsed and evaluated at runtime against fleet membership and monitor faults.

Health policies

health_policy SafetyPolicy {
    on Critical { enter degraded_mode; notify_operator; }
    on Failed { stop_all_actuators; audit.record("health_failed"); }
    on Unsafe { trigger kill_switch EmergencyStop; }
}

At runtime, matching reactions execute when health status transitions (wired to HardwareMonitor polling). Fleet-target checks are refined against fleet membership and member faults via apply_fleet_health_checks. Swarm programs log coordination events when fleet health is critical. Policies latch per (policy, status) until health returns to Healthy.

Example: examples/hardware/capability_verification.sd · Fleet requires: examples/features/fleet_health_require.sd

Typed handler returns

Return type annotations on behaviors, tasks, triggers, and events are documented in typed-handler-io.md.

Health triggers

on health Rover becomes Degraded {
    reduce_speed(0.5 m/s);
}

CLI

spanda health robot rover.sd
spanda health robot rover.sd --json
spanda trace health rover.sd
spanda verify rover.sd --health
spanda sim rover.sd --inject-health-faults