R.E. Merrill & Associates A2A API

openapi: 3.2.0
info:
  title: R.E. Merrill Pump Line Finder A2A API
  version: 1.0.0
  summary: Deterministic pump line selection from R.E. Merrill & Associates, over plain HTTP and over A2A JSON-RPC.
  description: R.E.
  contact:
    name: R.E. Merrill & Associates, Inc.
    email: info@remerrill.com
    url: https://www.remerrill.com/contact
  x-apievangelist-provenance:
    method: generated
    generated: '2026-09-19'
    generated_from:
    - https://www.remerrill.com/llms.txt
    - https://www.remerrill.com/.well-known/agent-card.json
    - POST https://www.remerrill.com/api/line-finder (documented example; HTTP 200 observed 2026-09-19)
    - POST https://www.remerrill.com/api/line-finder with an invalid body (HTTP 400 observed 2026-09-19)
    - 'GET https://www.remerrill.com/api/line-finder (HTTP 405 observed 2026-09-19); OPTIONS returned Allow: OPTIONS, POST'
    - POST https://www.remerrill.com/api/a2a SendMessage (documented example; HTTP 200 observed 2026-09-19)
    - POST https://www.remerrill.com/api/a2a GetTask with an unknown id (JSON-RPC error -32001 observed 2026-09-19)
    provider_publishes_openapi: false
    note: 'A generated contract, not a harvested one. Probed and absent on 2026-09-19: /openapi.json, /openapi.yaml, /swagger.json, /api/openapi.json, /api-docs, /docs (all real 404s).'
servers:
- url: https://www.remerrill.com
  description: Production. The apex remerrill.com 308-redirects every path to www.
tags:
- name: a2a
  description: The same line finder over the Agent2Agent protocol v1.0 (JSON-RPC 2.0).
paths:
  /api/a2a:
    post:
      tags:
      - a2a
      operationId: sendA2AMessage
      summary: A2A v1.0 JSON-RPC endpoint (SendMessage) for the same line finder
      description: 'Agent2Agent protocol v1.0 over JSON-RPC 2.0. Send the duty JSON as a message part (a data part, or the same JSON as text) with method SendMessage; the provider''s example sets an A2A-Version: 1.0 header. The agent is synchronous and stateless: a resolvable duty returns a completed task whose artifact (name line-finder-result) carries exactly the POST /api/line-finder response plus a text summary; a non-JSON natural-language message returns an agent message that restates the expected duty schema rather than guessing. Tasks are not retained after SendMessage, so GetTask answers JSON-RPC error -32001 Task not found (google.rpc.ErrorInfo reason TASK_NOT_FOUND) for any id; unknown methods return -32601 Method not found. No streaming, no push notifications, no authentication. GET returns 405 with a JSON pointer to the agent card. Discovery: https://www.remerrill.com/.well-known/agent-card.json.'
      parameters:
      - name: A2A-Version
        in: header
        required: false
        schema:
          type: string
          examples:
          - '1.0'
        description: Protocol version header the provider's own example sends.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/JsonRpcRequest'
            examples:
              send-duty:
                summary: The provider's documented SendMessage example
                value:
                  jsonrpc: '2.0'
                  id: 1
                  method: SendMessage
                  params:
                    message:
                      messageId: m1
                      role: ROLE_USER
                      parts:
                      - data:
                          fluid: sodium hypochlorite
                          concentrationPct: 12.5
                          flowGph: 2
                          pressurePsi: 40
                          service: feed
      responses:
        '200':
          description: A JSON-RPC 2.0 envelope — either a result (task with a line-finder-result artifact, or an agent message) or an error object. JSON-RPC errors are returned with HTTP 200.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/JsonRpcResponse'
              examples:
                task-not-found:
                  summary: Observed 2026-09-19 for GetTask with an unknown id
                  value:
                    jsonrpc: '2.0'
                    id: 3
                    error:
                      code: -32001
                      message: Task not found
                      data:
                      - '@type': type.googleapis.com/google.rpc.ErrorInfo
                        reason: TASK_NOT_FOUND
                        domain: remerrill.com
                        metadata:
                          taskId: apievangelist-nonexistent-probe
                          note: Tasks on this agent complete synchronously inside SendMessage and are not retained afterward.
                method-not-found:
                  summary: Observed 2026-09-19 for an unknown method
                  value:
                    jsonrpc: '2.0'
                    id: 2
                    error:
                      code: -32601
                      message: Method not found
        '405':
          description: GET is not served. Body is a JSON object with error, reason and agentCard (the discovery URL).
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                  reason:
                    type: string
                  agentCard:
                    type: string
                    format: uri
              example:
                error: Method not allowed
                reason: This is the A2A v1.0 JSON-RPC endpoint; POST a JSON-RPC 2.0 request. Agent discovery starts at the agent card.
                agentCard: https://www.remerrill.com/.well-known/agent-card.json
components:
  schemas:
    JsonRpcResponse:
      type: object
      required:
      - jsonrpc
      - id
      properties:
        jsonrpc:
          type: string
          const: '2.0'
        id:
          oneOf:
          - type: integer
          - type: string
        result:
          type: object
          description: 'On a resolvable duty: {task: {id, contextId, status: {state: TASK_STATE_COMPLETED, timestamp}, artifacts: [{artifactId, name: line-finder-result, description, parts: [{data: <LineFinderResult>}, {text: <summary>}]}]}}. On a non-JSON message: {message: {messageId, role: ROLE_AGENT, parts: [{text, mediaType: text/plain}]}} restating the expected duty schema.'
        error:
          type: object
          properties:
            code:
              type: integer
              description: -32001 Task not found (A2A TaskNotFoundError); -32601 Method not found.
            message:
              type: string
            data:
              type: array
              items:
                type: object
                description: google.rpc.ErrorInfo-shaped detail (@type, reason, domain, metadata).
    JsonRpcRequest:
      type: object
      required:
      - jsonrpc
      - id
      - method
      properties:
        jsonrpc:
          type: string
          const: '2.0'
        id:
          oneOf:
          - type: integer
          - type: string
        method:
          type: string
          description: A2A v1.0 method name. SendMessage is the implemented operation; GetTask answers -32001 for every id (tasks are not retained); anything else answers -32601.
          examples:
          - SendMessage
          - GetTask
        params:
          type: object
          description: 'For SendMessage: {message: {messageId, role: ROLE_USER, parts: [{data: <Duty>} | {text: "<Duty as JSON>"}]}}.'
externalDocs:
  description: Provider documentation (llms.txt) — the only published reference for this API
  url: https://www.remerrill.com/llms.txt