Substitutes fallback for a declared failure. A bug still rejects — a fallback that absorbed a TypeError would be the silent-bug-hider the two-tier rule exists to prevent.

Takes a value, not a thunk: unwrapOr(() => x) falls back to the function itself. For a fallback computed from the failure, use match({ ok: (v) => v, err: fn }) — same two-tier gate, and err runs only when there is one.

const loadConfig = () => Task(() => ({ port: 8080 }));
const DEFAULTS = { port: 3000 };

const config = await loadConfig().unwrapOr(DEFAULTS);