Device State Trust Verdict

Decide whether a device's reported state can be TRUSTED, before an automation acts on it. Zero runtime dependencies. Pure function: the caller supplies the reading and the clock, the library returns a verdict. No I/O.

THE SILENT FAILURE. An automation asks whether the door is closed. The sensor has been dead for a week -- flat battery, dropped off the Zigbee mesh, hub rebooted. Depending on HOW THE QUESTION WAS PHRASED, the automation gets OPPOSITE ANSWERS from the same dead sensor: 'is it open' is false, 'is it closed' is also false, and whichever branch the automation happened to write is the one that fires.

Neither answer is a lie, exactly. A dead sensor's last known value is genuinely 'closed', and its liveness is genuinely unknown -- but nothing in the reading separates those two facts, so the automation reads a stale value as a current one and locks the door, or leaves it unlocked, with full confidence.

THE VERDICT SEPARATES THEM. A state is TRUSTED, STALE, or NOT DETERMINABLE, and the action decision is made against that rather than against the raw boolean. An automation that cannot get a trusted reading is told so, and can hold rather than pick a branch on evidence that expired last Tuesday.

VERIFIED: 46 tests, measured by running the suite.

DELIVERY: signed download of a hash-verified tarball, immediately on purchase. Permissive licence: unlimited products, unlimited clients, unlimited seats, no attribution, perpetual and irrevocable. One restriction, do not republish the source as source.

Interface

What you call, and what comes back. Types and signatures only — the implementation ships with the source.

  export function decideAction<T, A>( verdict: TrustVerdict<T>, policy: TrustActionPolicy<T, A>, ): A;
  export function describeReason(reason: UntrustReason): string;
  export function resolveTrust<T>( reading: DeviceReading<T>, clock: TrustClock, ): TrustVerdict<T>;

  export type PlatformStatus = "available" | "unavailable" | "unknown";
  export type TrustVerdict<T> = TrustedVerdict<T> | UntrustedVerdict;