DetachableRunCapability

const DetachableRunCapability: Capability<true, "detachable-run">;

Defined in: packages/ai/src/activities/chat/middleware/run-store.ts:375

Whether the current run can be DETACHED rather than destroyed when its client disconnects — true only when some middleware has both a RunStore and a durable event log wired (withSandbox's runs + durability.adapter).

Lives in core for the same reason LockStore does: it is a coordination fact that two consumer packages must agree on, and neither may depend on the other. @tanstack/ai-sandbox provides it; @tanstack/ai-persistence reads it to decide whether an abort is terminal ('aborted') or a detach (write nothing). A persistence → sandbox import would be a layering inversion.

Consumers read it with { optional: true }: absent means "not detachable", which is every app that has not wired durability.

Typed true, not boolean: ABSENCE is the negative, so a published false has no meaning — and a consumer that tests PRESENCE rather than the value would read one as "detachable". Narrowing the payload makes that unrepresentable instead of merely undocumented.