Errors

import {
  MPCKitError,
  MPCKitInsufficientCreditsError,
  MPCKitTimeoutError,
} from "@mpckit/sdk";

try {
  await api.sign(args);
} catch (e) {
  if (e instanceof MPCKitInsufficientCreditsError) {
    // surface a "top up credits" UI
  } else if (e instanceof MPCKitTimeoutError) {
    // polling exceeded args.timeoutMs; the sign session may still
    // complete on the backend. Use the raw client to poll
    // /v1/sign/:id by the signRequestId from a previous response.
  } else if (e instanceof MPCKitError) {
    // any other typed API error
  } else {
    throw e;
  }
}

Error classes

Class	Thrown when
`MPCKitError`	Base class. Any HTTP error the backend returned with a structured body.
`MPCKitInsufficientCreditsError`	Project balance can't cover the op. Status 402, code `INSUFFICIENT_CREDITS`. Top up and retry.
`MPCKitTimeoutError`	Polling exceeded `timeoutMs`. The op may still finish; poll the request by id via `api.raw`.

MPCKitError carries the HTTP status, the backend's error code, the raw response body, and a human-readable message:

catch (e) {
  if (e instanceof MPCKitError) {
    console.error(e.status, e.code, e.message);
    console.error(e.body); // raw response body the backend returned
  }
}

MPCKitTimeoutError is a plain Error subclass: it has a name and message only. To resume a timed-out sign session, hold onto the signRequestId you got from a prior call (or a previously issued idempotencyKey) and re-query the request via the raw HTTP client.

Recovering from a sign timeout

import { MPCKitTimeoutError, newIdempotencyKey } from "@mpckit/sdk";

const idempotencyKey = newIdempotencyKey();

try {
  return await api.sign({ /* ... */, idempotencyKey });
} catch (e) {
  if (e instanceof MPCKitTimeoutError) {
    // safe to retry with the same idempotency key: the backend
    // dedupes and returns the original sign session.
    return await api.sign({ /* ... */, idempotencyKey });
  }
  throw e;
}

Reusing the same idempotencyKey is the simplest recovery path because the backend dedupes on it; a retried call returns the original signature instead of triggering a second on-chain session.

Errors

Error classes

Recovering from a sign timeout

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