@peac/schema is Layer 1 of the PEAC protocol stack. It provides Zod schemas for all receipt claim types (both the legacy peac-receipt/0.1 wire format and the current stable Interaction Record format), typed extension group accessors, evidence validation with DoS protection, and pure utility functions such as computeReceiptRef(). It depends only on @peac/kernel and Zod, performs no I/O, and has no side effects.

How Do I Use It?

Parse and classify receipt claims

import { parseReceiptClaims } from '@peac/schema';

const result = parseReceiptClaims(decodedPayload);

if (result.ok) {
  console.log(result.variant); // 'commerce' | 'attestation' | 'wire-02'
  console.log(result.wireVersion); // '0.1' | '0.2'
  console.log(result.claims.iss); // validated issuer
  console.log(result.warnings); // VerificationWarning[]
}

Validate Interaction Record claims with extension accessors

import { Wire02ClaimsSchema, getCommerceExtension, getAccessExtension } from '@peac/schema';

const claims = Wire02ClaimsSchema.parse(decoded);

const commerce = getCommerceExtension(claims.ext);
if (commerce) {
  console.log(commerce.rail); // e.g. 'stripe'
  console.log(commerce.amount_minor); // string, e.g. '1999'
  console.log(commerce.cur); // e.g. 'USD'
}

const access = getAccessExtension(claims.ext);
if (access) {
  console.log(access.resource); // accessed resource URI
}

Compute a content-addressed receipt reference

import { computeReceiptRef } from '@peac/schema';

const ref = await computeReceiptRef(compactJws);
// 'sha256:a1b2c3...' (deterministic, requires WebCrypto)

Validate evidence before signing

import { validateEvidence } from '@peac/schema';

const result = validateEvidence(evidenceObject);
if (!result.valid) {
  console.log(result.error); // validation failure details
}

Validate an evidence carrier against transport limits

import { validateCarrierConstraints, CARRIER_TRANSPORT_LIMITS } from '@peac/schema';
import type { PeacEvidenceCarrier, CarrierMeta } from '@peac/kernel';

const carrier: PeacEvidenceCarrier = {
  receipt_jws: jws,
  receipt_ref: ref,
};

const meta: CarrierMeta = {
  transport: 'mcp',
  format: 'embed',
  max_size: CARRIER_TRANSPORT_LIMITS.mcp,
};

const result = validateCarrierConstraints(carrier, meta);
// result.valid: boolean, result.violations: string[]

Integrates With

@peac/kernel (Layer 0): Types and constants that schemas validate against
@peac/crypto (Layer 2): Signing and verification using validated claims
@peac/protocol (Layer 3): High-level issuance and verification built on these schemas
@peac/mappings-* and @peac/adapter-* (Layer 4): Transport-specific carrier validation and external system mapping

For Agent Developers

If you are building an AI agent or MCP server that issues or verifies signed interaction receipts, you typically will not use @peac/schema directly. Start with @peac/mcp-server for a ready-to-use MCP tool server, or use @peac/protocol for programmatic receipt issuance and verification. Reach for @peac/schema when you need fine-grained control over claim parsing, extension group access, or carrier validation in a custom integration.

For Operators

Operators deploying PEAC infrastructure can use @peac/schema to validate receipt claims at ingestion boundaries, enforce kernel constraints with validateKernelConstraints(), and verify carrier size limits per transport before forwarding evidence across services.