Type Alias: Observability

Observability = "state-delta" | "postcondition" | "navigation" | "external" | "unobservable"

Defined in: src/atom/types.ts:283

HOW WOULD ANYONE SEE THAT THIS ACTION HAPPENED — the app's own answer, declared once next to the action.

Five words, and the split that matters runs between the first two:

• 'state-delta' — the declared writes appear in a reported delta. THIS IS KEY PRESENCE, NOT VALUE CORRECTNESS: a handler that wrote orderId: null satisfies it exactly as a real order does. Nothing in this library ever claims more of it, and EffectPolicy refuses it as a verification for precisely that reason.
• 'postcondition' — the app declared a VerifyContract: a real check, asked once, at settlement.
• 'navigation' — the effect IS page motion, to the destination the action declares. Corroborated by a later sync() (TransitionRecord.arrival), which is corroboration and never causal proof.
• 'external' — it happens somewhere this client cannot see (a payment processor, a queue). The app reports completion through Session.observeEffect; the library records the reference and invents nothing.
• 'unobservable' — the app itself says nobody can tell from here. An honest answer, and the one a high-effect policy will not accept.

DECLARED, NEVER INFERRED — the law writes and reads live under. The library does not read your handler, watch the DOM, or promote a writes list into an answer. An app that declares nothing behaves and serves identically.