Ui Hooks

useChat's `status` field cycles 'submitted' → 'streaming' → 'ready' (or 'error'). Operator disables the send button only when `isLoading` and finds no such property exists in current versions.

Read `status` and disable input when status is 'submitted' or 'streaming'. The legacy `isLoading` boolean is removed in current major versions — migrate to `status`. Surface 'error' status with a retry control.

User clicks a 'Stop' button to abort a long generation; useChat's stop() is called. Server keeps generating because the route handler did not forward the abort.

useChat's stop() aborts the fetch on the client. The server route must propagate the request's AbortSignal (Next.js `request.signal`) into the SDK call (`streamText({ abortSignal: request.signal, ... })`) so upstream provider billing stops. Without the wire-through, only client-side rendering halts.

Form UI streams a structured-object response into a partially-populated form. Operator implemented this with useCompletion and manual JSON.parse on every token, which throws often.

Use `useObject({ api, schema })` — the hook yields `object` typed as deeply-partial of the schema, plus `submit()`, `isLoading`, `error`. The hook tracks partial JSON parsing across token boundaries so the form re-renders cleanly. Do not roll your own JSON-stream parser.