Mantle

Mantle holds on to something you are trying to get done while it is still unfinished — a journey, an errand, a repair — and keeps it valid as the world moves. It works through whichever device is to hand: a phone, a watch, a small board on a desk, a laptop. You are not asked to hold the state in your head, and not asked to translate an intention into a sequence of applications. The agent looks after the undertaking and comes to you when your judgement is actually required, on whichever surface you are nearest.

Today's assistants hand the loop back to the person. State lives in someone's head or scattered across applications, each device keeps its own fragment, and every step needs a fresh instruction. The result is an assistant that answers questions but cannot be left to look after anything — and a person spending their attention as a translation layer between what they want and the software that could do it. Continuity is treated as a feature of a device or an account, so it breaks the moment either changes.

Arc's position is that continuity and authority belong in a layer above the device and above the application. An agent may act, but only inside a boundary a person granted; a person should be addressable from the work rather than responsible for carrying it; and the device should be a replaceable participant, never the home of the undertaking. The mechanism is protected — a provisional patent was filed in July 2026 — and the implementation detail stays held. The public claim is the narrower and sufficient one: that this layer is where the problem actually lives. Mantle is the successor to Arc's first embodied line, rebuilt around a different ontology.

Prototype · provisional filed