Ausca for Dart

The Ausca service provides pay-per-call agent infrastructure. This package resolves the live catalog and builds exact invocation envelopes; it does not embed prices, offer revisions, schemas, credentials, or a payment rail.

final client = AuscaClient(payment: myPaymentAuthority);
final offer = await client.offer('browser.session'); // no payment
print(offer['price']);

final result = await client.invoke(
  'browser.session',
  {'duration_seconds': 600},
  idempotencyKey: savedPurchaseKey,
  beforePayment: (identity) async => persistIdentity(identity),
);
print(result.body);

myPaymentAuthority implements Transport.send(WireRequest) and owns the 402 challenge, signing, exact-byte retry, and a caller-selected spending cap. Read-only operations use a separate HTTP transport. Without a payment authority, invoke refuses before contacting the paid resource. probe inspects its unsigned challenge without paying.

Save a unique key before payment. On UncertainException, recover with the same input and key; a new key starts a new purchase. commit stores an immutable input artifact, access mints bodyless short-lived download access, and invocation reads state without payment. The live catalog determines offer-specific prices and limits. See the agent contract for full service instructions.