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ANP/0.1

ANP/0.1 · an open protocol · MIT

AI agents negotiating commercial terms, on a record both sides can verify.

ANP lets a vendor’s selling agent and a buyer’s negotiation agent conduct a negotiation over HTTPS with signed identity, an explicit mandate exchange, structured offers, and a hash chained session log that neither side can rewrite undetected.

Read the specTry the sandboxImplement it

Four guarantees

The protocol is a transport, not a policy engine. It never expands an agent’s authority; it makes what each agent does auditable.

01

Authenticated identity

Every request is signed with a registered Ed25519 key. There are no anonymous participants, and every agent declares that it is an AI.

02

Mandate exchange

Each side opens by declaring what its agent may discuss, what it may disclose, and what authority it carries. Overreach becomes provable from the log.

03

Structured offers

Offers and counter-offers are strict JSON with line items, quantities, unit prices, term and expiry, so both sides can parse, compare, and audit them mechanically.

04

A verifiable log

Every event appends to a SHA-256 hash chain. Either side can re-verify the whole log at any time; neither side, including the host, can rewrite history undetected.

What it looks like on the wire

A structured offer

Event 3 of the bundled example session. Strict schema, unknown keys rejected, required expiry so nothing dangles.

{
  "currency": "USD",
  "term_months": 12,
  "expires_at": "2026-08-01T00:00:00Z",
  "line_items": [
    {
      "description": "CRM Enterprise seats",
      "quantity": 500,
      "unit": "seat/year",
      "unit_price": 1200,
      "currency": "USD"
    }
  ],
  "conditions": [
    "Net 30 payment"
  ]
}

The hash chain

Every event binds to its predecessor. Change one byte anywhere and every verifier sees exactly where the chain broke.

  1. seq 2envelopebuyer

    prev_hash
    b0fb26906b528a6f1fc0124f…
    event_hash
    ac18d8ae6789ea9822c881db…

  2. seq 3offervendor_agent

    prev_hash
    ac18d8ae6789ea9822c881db…
    event_hash
    1325320eedb628abdaf29557…

  3. seq 4counter_offerbuyer

    prev_hash
    1325320eedb628abdaf29557…
    event_hash
    74c509ce62d05f538f6d8634…

Each prev_hash equals the previous event_hash. Verify this chain yourself in the playground.

An open standard with many implementations beats a proprietary channel with one.

MIT licensed. Anyone, including competitors, may implement ANP without permission.

See implementationsGovernance