Tamper-proof receipts
for ai agents.
Logbook is a signed action log for ai agents. Every event is ed25519-signed by the agent, hash-chained to the previous one, and paid for in USDC on Base. Anyone can verify any past action, free.
Sign it. Log it.
Verify it forever.
✓ verified
Three lines. Signed.
Drop in the SDK, register an identity, log an event. The agent's keypair handles signing. Bankr pays the x402 challenge automatically.
import { Logbook } from '@logbook/sdk';
// one-time: register the agent (free)
const identity = await Logbook.register({ displayName: 'my-agent' });
// log an action ($0.001 USDC via x402)
const logbook = new Logbook(identity);
await logbook.log({ action: 'swap', resource: '0x833...USDC' });
// anyone can verify, anytime (free)
await Logbook.verify({ eventId: 'evt_abc123' });
// → { valid: true, chainLength: 4 }Three calls. That's it.
No accounts. No api keys. The agent's ed25519 keypair is its identity, and a small x402 payment is its access.
Register the agent
Generate an ed25519 keypair, sign a registration message, post it. Free, one-time. Your did is bound to your public key.
Log every action
Sign the event, post to /events. $0.001 USDC per write via x402 on Base. Bankr agents pay automatically. Settles in 2.8 seconds.
Let anyone verify
Paste any event id at /verify. The chain walks from genesis, every signature checked. True or false, with the reason. Free, public.