openapi: 3.2.0
info:
  title: IAB Agentic Advertising Negotiations API
  version: 0.1.0
  description: 'Canonical wire protocol between the IAB Tech Lab buyer and seller agents: catalog, quote->book deal flow, negotiation, change requests, A2A (Agent-to-Agent protocol) JSON-RPC messaging, and Agent Card discovery.'
tags:
- name: Negotiations
paths:
  /api/v1/negotiations/messages:
    post:
      operationId: sendNegotiationMessage
      summary: 'One negotiation move: offer/counter/accept/decline via the required action enum…'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: ../jsonschema/protocol/NegotiationMessage.json
      responses:
        '200':
          description: The seller's move for this round.
          content:
            application/json:
              schema:
                $ref: ../jsonschema/protocol/NegotiationRoundResponse.json
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '409':
          description: Terminal negotiation (error=negotiation_closed) or round-number mismatch (error=contention).
          content:
            application/json:
              schema:
                $ref: ../jsonschema/protocol/ErrorEnvelope.json
      tags:
      - Negotiations
  /api/v1/negotiations/{negotiation_id}:
    get:
      operationId: getNegotiation
      summary: Full negotiation history (the Negotiation primitive)
      parameters:
      - name: negotiation_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: The negotiation with its round history.
          content:
            application/json:
              schema:
                $ref: ../jsonschema/Negotiation.json
        '404':
          $ref: '#/components/responses/Error'
      tags:
      - Negotiations
components:
  responses:
    Error:
      description: 'Structured error envelope: {"detail": {"error": <ErrorCode>, "message": "...", "unsupported": [...]}}.'
      content:
        application/json:
          schema:
            $ref: ../jsonschema/protocol/ErrorEnvelope.json