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?
An AI receipt (or PEAC-Receipt) is a cryptographically signed JSON object that proves what happened during an agent interaction. Just like a physical receipt from a store, it records who transacted, what was exchanged, when it happened, and under what terms.
The key difference: AI receipts are machine-readable, tamper-proof, and verifiable by anyone with the issuer's public key - no phone call to customer service required.
Why Receipts Matter
Billing proof
No more "he said, she said" disputes. The signature proves what was used.
Audit trails regulators accept
Timestamped, tamper-evident records of every agent action. GDPR, SOC 2, EU AI Act compliance becomes straightforward when you can produce signed receipts on demand.
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 (GDPR, SOC2, etc.)
- Agent frameworks - Collect receipts to track costs and prove work completion
Implementation
Start working with receipts using Originary's tools: