Device traits

switchable (switchable, adjective) provides the on/off state. Chord composes it off by default, and starts on seeds it running (ADR-231; chord-language.md), as with the fan. The trait also carries a power model (requiresPower, hasPower, powerConsumption, which drives the no_power refusal), on/off/running sounds (fed into the sound message keys and event payloads), swap-in onDescription/offDescription text, and detailWhenOn, the appended examine sentence, which is exactly what Chord's phrase detail while it is on: lowers to (the zoo's radio and flashlight both use it). Two features are dormant today: the auto-off timer (autoOffTime is honored at switch-on but nothing ticks the countdown) and the per-trait message overrides (onMessage/alreadyOnMessage/…), both of which are flagged.

light-source (light-source, adjective) makes a switchable shed light: isLit (managed by the switching actions), brightness, litDescription/unlitDescription, and detailWhenLit, which is Chord's phrase detail while it is lit:, the safelight's examine line. The fuel model (fuelRemaining, where empty refuses to light; maxFuel, consumption rate) is dormant on the consumption side: nothing burns fuel per turn today, so a lantern only runs out if story logic decrements it. The zoo flashlight (light-source, switchable) is the shipped example.

button (trait, TypeScript-only, and mostly decorative) carries descriptive fields (color, size, shape, label, latching); its one live effect is in pushing: a pushable button that is also switchable toggles, and the BUTTON trait upgrades the message to button_clicks. Worth knowing: pushing's toggle flips the switch state but, unlike the switching actions, does not light or extinguish an attached light source, so wire light-buttons through after pushing it story logic (flagged as an inconsistency).