Buyer agents and seller agents: negotiating and closing B2B deals

How it works today

Most B2B deals close through people. A buyer asks for pricing, a sales representative sends a quote, the two sides trade counteroffers by email and calls, and the result becomes an order form or contract that an authorized signatory signs. Internal approval steps sit on both sides: a discount above a threshold needs a sales manager, and a purchase above a threshold needs finance. The procurement use case covers the formal RFQ and purchase order documents. This page is about the negotiation and the moment a deal becomes binding.

Agent protocols so far cover the end of the process. AP2 v0.2 defines Checkout and Payment Mandates that let an agent’s user authorize a purchase and a payment, and AP2 is being donated to the FIDO Alliance. It does not cover the back-and-forth over price, term and conditions that comes first.

The law already contemplates software making deals:

• United States, federal. E-SIGN (15 U.S.C. 7001(h)) says a contract cannot be denied legal effect solely because electronic agents were involved in forming it, as long as each agent’s action is legally attributable to the person to be bound.
• United States, state. The Uniform Electronic Transactions Act, as enacted in states such as California (Civil Code 1633.14), says a contract may be formed by the interaction of the parties’ electronic agents even if no individual was aware of or reviewed the agents’ actions or the resulting terms.
• Canada (Ontario). Ontario’s Electronic Commerce Act, 2000 defines an electronic agent as a program or other electronic means that acts or responds without review by an individual at the time. Section 20 says a contract may be formed by the interaction of electronic agents. Section 21 makes a transaction between an individual and another person’s electronic agent unenforceable by that person after a material error, if the agent gave no chance to prevent or correct it, the individual promptly gives notice, and the individual returns or destroys any consideration received without benefiting materially.
• International. UNCITRAL adopted the Model Law on Automated Contracting on 11 July 2024. It gives legal recognition to contracts formed and performed with automated systems, sets rules for attributing a system’s outputs to a party, offers an optional rule on unexpected outcomes, and says automation cannot be used to avoid or excuse non-compliance with other legal requirements. Countries must enact it before it applies.

For goods sold in the US, UCC 2-207 adds a familiar complication: an acceptance or confirmation can still form a contract when it adds or changes terms, and between merchants some of those terms become part of the deal. Agents that negotiate by exchanging slightly different term sets inherit that problem.

The agent-to-agent version

Illustrative. A buyer’s agent is negotiating 1,200 software seats. The seller’s agent makes a firm counteroffer and marks it as such, in A2A v1.0 shapes:

{
  "id": "task-deal-8841",
  "contextId": "ctx-deal-8841",
  "status": {
    "state": "TASK_STATE_INPUT_REQUIRED",
    "timestamp": "2026-10-20T13:45:00Z",
    "message": {
      "messageId": "msg-deal-8841-05",
      "taskId": "task-deal-8841",
      "contextId": "ctx-deal-8841",
      "role": "ROLE_AGENT",
      "parts": [
        { "text": "Counteroffer: 1,200 seats for 36 months at 31.50 per seat per month, billed annually in advance. This offer is firm until 17:00 Eastern on 24 October 2026." },
        {
          "data": {
            "offerId": "OFR-8841-3",
            "offerType": "firm",
            "supersedes": "OFR-8841-2",
            "quantity": 1200,
            "unitPrice": "31.50",
            "currency": "USD",
            "termMonths": 36,
            "billing": "annual-in-advance",
            "expires": "2026-10-24T21:00:00Z",
            "acceptanceRequires": "buyer-authorized-signatory"
          },
          "mediaType": "application/json"
        }
      ]
    }
  }
}

Then:

1. The buyer’s agent checks the offer against the limits its company set: maximum unit price, term and payment terms.
2. Inside those limits, it asks the named approver to confirm, as the offer itself requires a signatory. Outside them, it counters or stops.
3. The approver accepts. The buyer’s agent sends an acceptance that cites OFR-8841-3 exactly, with no added terms.
4. The seller’s agent completes the task with the order form as an artifact. Payment follows through invoicing or, for agent-initiated payments, through a payment protocol such as AP2.

What has to be true

Identity. Each side must know which company the other agent represents. A Signed Agent Card proves who holds the signing key; binding that key to a company is a separate check.

Authority and attribution. E-SIGN turns on whether an agent’s action is legally attributable to the person bound, and UNCITRAL’s model law adds attribution rules of its own. Each company therefore needs a clear, checkable statement of what its agent may commit to: price ceilings, discount floors, term lengths, and when a person must sign. A2A leaves the form of such authority credentials to implementations and extensions (section 7.6.4).

Record. Offers, counteroffers and acceptances need identifiers, timestamps, expiry and a clear chain of which offer superseded which. Labeling each message as firm or indicative avoids arguments over whether an agent’s price was an offer at all.

Errors. Agents misread inputs and occasionally act unexpectedly. Ontario’s section 21 protects an individual who deals with another person’s agent, not two agents dealing with each other, and UNCITRAL’s rule on unexpected outcomes is optional. Contracts between the companies should say how agent errors are handled.

Competition. Seller agents set prices from data. In its January 2026 report on algorithmic pricing, the Competition Bureau listed collusion among the anti-competitive concerns respondents raised. Negotiating agents should never receive or share competitors’ confidential pricing.

Where Emissar fits

• Front Door (Open to design partners): a hosted A2A endpoint where a seller exposes quoting and negotiation skills in front of its pricing and CRM systems.
• Verify (In development): checks which company the counterpart agent represents before terms are exchanged.
• Mandate (Spec in progress): a proposal for a scoped, revocable statement of what an agent may commit to, which the other side can check.
• Ledger (Spec in progress): a signed, tamper-evident record of each offer and acceptance, retrievable by both parties.
• Settle (Planned): moves money when a deal ends in a payment, on AP2 and x402, checked against Mandate limits.
• Handoff (In development): sends offers outside an agent’s limits to the person who can approve them, with the negotiation attached.

Open questions

• Should agents be required to mark every price as firm or indicative, and will A2A extensions standardize that?
• How will a seller prove, after a dispute, that an acceptance was attributable to the buyer’s company and within its agent’s authority?
• Which jurisdictions will enact UNCITRAL’s model law, and will they adopt the optional rule on unexpected outcomes?
• If many sellers use the same pricing agent or data provider, where does competition law draw the line?