Key Takeaways
- Receipts are JWS-signed JSON proving what happened in an interaction
- Verifiable offline using public keys. No API callback.
- Carried in the PEAC-Receipt HTTP header
What is a Receipt?
A PEAC interaction record is a JWS-signed JSON payload that records what happened during an agent interaction: who issued it, what resource was accessed, when, under what terms, and with what payment (if any). The signature uses Ed25519.
Anyone with the issuer's public key can verify the record offline. No API callback, no trust in the verifier, no phone call. The record travels in the PEAC-Receipt HTTP header as a compact JWS string.
Why Receipts Matter
Billing proof
The signed record proves which resource was accessed and what was paid. Disputes resolve by checking the signature, not by arguing about server logs.
Audit trails
Timestamped, tamper-evident records of every agent action. When a regulator asks what your agent did, you produce the signed records. They verify independently.
Attribution chains
Content usage gets recorded. Creators verify credit and compensation.
Anatomy of a PEAC-Receipt
A PEAC-Receipt contains several key fields:
{
"iss": "api.example.com", // Issuer
"sub": "agent-xyz-123", // Agent ID
"aud": "originary.xyz", // Audience
"iat": 1702834800, // Issued at
"exp": 1702921200, // Expiration
"rid": "rcpt_abc123", // Receipt ID
"resource": "/v1/translate", // Resource accessed
"action": "POST", // HTTP method
"payment": {
"amount": "0.001",
"currency": "USD",
"evidence": "pi_xxx" // Payment proof
},
"aipref_hash": "sha256:abc..." // Policy snapshot
}The entire payload is signed using JWS (JSON Web Signature), typically with Ed25519. The signature can be verified using the issuer's public key referenced in /.well-known/peac.txt (which points to a JWKS endpoint).
Use Cases
- API providers - Issue receipts to prove service delivery; resolve billing disputes instantly
- Content platforms - Track AI consumption of licensed content with verifiable attribution
- Enterprise AI - Maintain audit trails for regulatory compliance workflows
- Agent frameworks - Collect receipts to track costs and prove work completion
Implementation
Start working with receipts using Originary's tools: