Specification · section 15

Conformance

Level	Requirements
MHP Core	`initialize`, `ping`, `device/describe` (all three tiers and `select`), `resources/*`, `signals/read`, `settings/write` with limit enforcement, the error codes in §12.
MHP Actions	Core plus `actions/invoke`, `jobs/`, `notifications/jobs/`, interlock and approval gates.
MHP Safe	Actions plus `safety/estop`, `safety/reset`, watchdog, fail-closed state machine, `session/*` leases.
MHP Directory	Server role: `initialize` with `role: "directory"`, `directory/search`, `directory/get`, `directory/stats`. Indexes cards only.

Devices that carry stored energy or can move SHOULD NOT be exposed below MHP Safe. All device levels MUST support detail and select on device/describe.