openapi: 3.2.0
info:
  title: IAB Agentic Advertising A2a 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: A2a
paths:
  /a2a/jsonrpc:
    post:
      operationId: a2aMessageSend
      summary: 'A2A JSON-RPC endpoint, ONE method: message/send (the A2A-spec dialect).'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: ../jsonschema/protocol/JsonRpcRequest.json
      responses:
        '200':
          description: JSON-RPC response (exactly one of result/error).
          content:
            application/json:
              schema:
                $ref: ../jsonschema/protocol/JsonRpcResponse.json
      tags:
      - A2a