Shared attachments, pending/error, and stable mutation methods.
import { useModelContext } from "mcp-use/react";
function Selection() {
const { add, pending, error } = useModelContext();
async function select() {
try {
await add("selected-item", { type: "text", text: "Selected item: Blue mug" });
} catch (error) {
console.error("Could not deliver model context", error);
}
}
return (
<>
<button disabled={pending} onClick={select}>Share selection</button>
{error && <p role="alert">{error.message}</p>}
</>
);
}
Manage native model context through the view's shared, single writer.
Mounting this hook activates native context delivery for the runtime; no view configuration is needed. Legacy-only views retain their transport. Existing model-visible widget persistence prevents an unsafe handoff and surfaces an error; the SDK never silently clears that state. Attachment keys are shared across all hook instances. Unmounting a consumer does not clear selections. Exact duplicate blocks under different keys reject.
Image src inputs resolve like Image public assets and are fetched before replacing the selection; direct data plus mimeType remains supported. Text thumbnail src uses the same resolver and remains a URL. Later same-key actions or clear cancel image preparation and settle it as superseded. Calls await initialization and negotiate support internally. Successful calls acknowledge context delivery, not composer rendering. Host removals update the selection where unambiguous. Uncertain writes or host ordering pause publication until a fresh runtime can initialize after outstanding writes stop. Definite failed writes retain the requested selection and reject. The next valid mutation makes one fresh attempt; background updates do not retry.
Keep removable evidence out of duplicate view state or description fields. Audience annotations affect presentation, not access by the model.