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A request is not an authority — the four-layer chain

concept

A request layer may PROPOSE an action; a separately governed layer admits only a bounded capability; an execution layer may carry out only pre-approved motions; and a reflex layer continuously limits the physical envelope — pressure, flow, current, force, speed, balance, and joint state. Independent sensors witness the result, and the record is sealed outside the requesting process. Stated for a controlled machine, this is the general law the other documents restate in their own materials: intelligence may PROPOSE; a separate, independently governed layer determines what may actually happen; and the record of what happened is kept somewhere the requester cannot reach. The value is in the separation, not in any one layer's cleverness. WHERE IT ALREADY BEARS WEIGHT — Already load-bearing here: `shelves.curate` refuses a typed name as authority and keeps the check in the module so neither the HTTP nor the MCP door can bypass it; `consent.guard()` admits a bounded capability for an agent; every curation act is sealed with a steward and a reason in an append-only record the actor cannot edit.

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