Key Takeaways
- Receipts are JWS-signed JSON proving what happened in an agent interaction
- Enable billing, compliance, attribution, and dispute resolution
- Verifiable offline using public keys - no API call required
- Carried in the PEAC-Receipt HTTP header on every transaction
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 & Metering
Receipts provide irrefutable proof of API consumption. No more “he said, she said” billing disputes - the cryptographic signature proves exactly what was used.
Compliance & Audit
Regulators increasingly require audit trails for AI systems. Receipts provide timestamped, tamper-evident records of every agent action.
Attribution & Provenance
When an agent uses content or data, the receipt records proper attribution. Content creators can verify their work was properly credited and compensated.
Dispute Resolution
When something goes wrong, receipts provide the evidence chain. Both parties can present their receipts to resolve conflicts objectively.
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: