Run broken-refund scenarios through Postcept's verification engine, in your terminal:
npx @postcept/demo
Each scenario (a Stripe call that timed out before the write, a retry that refunded twice, a settlement still pending, a wrong amount, a provider outage, an unknown provider status) runs through the real engine and shows what the agent claimed, what the system of record held, and what Postcept concluded: the outcome, the lifecycle, and whether it is safe to tell anyone the work is done.
No account, no setup. The engine is the production one, reached through the public
playground endpoints. The ledger is example data. Receipts come back Ed25519
signed with test: true in the signed body, so you can verify one at
https://postcept.com/verify.
npx @postcept/demo --list # scenarios
npx @postcept/demo duplicate # run one
Web version: https://postcept.com/lab