@accord-protocol/core

Core SDK for Accord Protocol. Canonicalize, hash, and validate the three v0 protocol objects.

Public docs: Learn · Status · Repository

The three v0 protocol objects:

| Object | Spec | Type literal | |---|---|---| | Agreement | ACCORD-001 | accord.agreement.v0 | | Verification Receipt | ACCORD-002 | accord.verification_receipt.v0 | | Settlement Receipt | ACCORD-003 | accord.settlement_receipt.v0 |

This package is rail-agnostic. It knows nothing about Ergo, Base, Rosen, or x402 — those live in @accord-protocol/rails-* adapters.

Install

npm install @accord-protocol/core

Usage

Hashing

import { accordHashV0, withPrefix } from "@accord-protocol/core";

const agreement = { /* …matches schemas/agreement.v0.schema.json… */ };
const hex   = accordHashV0(agreement);          // "a1b2c3…"  (64 lower-case hex)
const wire  = withPrefix(hex);                  // "blake2b256:0xa1b2c3…"

accord_hash_v0 = BLAKE2b-256(canonical_json_bytes(object)). The wire form (blake2b256:0x…) is what agreement_hash / verification_receipts[i] carry inside protocol objects.

Signing a Verification Receipt

The signing input is the receipt with the signature field stripped, canonicalized, then BLAKE2b-256-hashed:

import { signingHashRaw } from "@accord-protocol/core";

const signingInput = signingHashRaw(receipt);  // 32-byte digest
const signature = sign(privateKey, signingInput);
receipt.signature = { scheme: "ed25519", public_key, signature };

Validating

import {
  validateAgreement,
  validateVerificationReceipt,
  validateSettlementReceipt,
} from "@accord-protocol/core";

const r = validateAgreement(agreement);
if (!r.ok) {
  for (const p of r.problems) console.error(p.code, p.path, p.message);
}

Validation enforces the cross-field rules that JSON Schema can't easily express — see src/validate.ts for the full list. Use it alongside JSON-Schema validation against schemas/, not instead of it.

Per-rail mode allow-list

import { RAIL_MODE_ALLOWLIST } from "@accord-protocol/core";

RAIL_MODE_ALLOWLIST.ergo
// → ["note_redeemed", "reserve_refunded", "batch_settled"]

What's NOT in this package

• Rail adapters (Ergo / Rosen / Base / x402) → @accord-protocol/rails-*
• HTTP transport (Accord/402) → @accord-protocol/gateway
• MCP transport (Accord/MCP) → @accord-protocol/mcp
• Conformance suite → @accord-protocol/conformance
• Signing / verification primitives — bring your own libsodium / secp256k1 / ergo-sigma binding; this package only computes the signing-input hash.

License

MIT.