### 1 · SendMessage: the full suite
POST /a2a/jsonrpc HTTP/1.1
Host: localhost:41241
Content-Type: application/json
A2A-Version: 1.0

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "SendMessage",
  "params": {
    "message": {
      "messageId": "7b89296c-6dcb-4c50-8857-7eb1924770d3",
      "role": "ROLE_USER",
      "parts": [
        {
          "text": "Run the full suite for payments-api at commit 9f3c2e1"
        }
      ]
    },
    "configuration": {
      "returnImmediately": true
    }
  }
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "task": {
      "id": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
      "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
      "status": {
        "state": "TASK_STATE_SUBMITTED",
        "timestamp": "2026-10-06T09:00:03.250Z"
      },
      "history": [
        {
          "messageId": "7b89296c-6dcb-4c50-8857-7eb1924770d3",
          "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
          "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
          "role": "ROLE_USER",
          "parts": [
            {
              "text": "Run the full suite for payments-api at commit 9f3c2e1"
            }
          ]
        }
      ]
    }
  }
}

### 2 · CancelTask
POST /a2a/jsonrpc HTTP/1.1
Host: localhost:41241
Content-Type: application/json
A2A-Version: 1.0

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "CancelTask",
  "params": {
    "id": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf"
  }
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "id": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
    "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
    "status": {
      "state": "TASK_STATE_CANCELED",
      "message": {
        "messageId": "9f730657-74a7-43df-b405-5a8270fe73a9",
        "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
        "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "Canceled at the client's request."
          }
        ]
      },
      "timestamp": "2026-10-06T09:00:03.750Z"
    },
    "history": [
      {
        "messageId": "7b89296c-6dcb-4c50-8857-7eb1924770d3",
        "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
        "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
        "role": "ROLE_USER",
        "parts": [
          {
            "text": "Run the full suite for payments-api at commit 9f3c2e1"
          }
        ]
      },
      {
        "messageId": "4e4233ac-1dca-4ecc-8b5f-0a7afff7c0bf",
        "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
        "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "Checking out 9f3c2e1 and starting the suite"
          }
        ]
      }
    ],
    "artifacts": [
      {
        "artifactId": "test-log",
        "name": "test-log.txt",
        "parts": [
          {
            "text": "tests/test_suite_01.py ........\n"
          },
          {
            "text": "tests/test_suite_02.py ........\n"
          }
        ]
      }
    ]
  }
}

### 3 · CancelTask: again
POST /a2a/jsonrpc HTTP/1.1
Host: localhost:41241
Content-Type: application/json
A2A-Version: 1.0

{
  "jsonrpc": "2.0",
  "id": 3,
  "method": "CancelTask",
  "params": {
    "id": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf"
  }
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 3,
  "error": {
    "code": -32002,
    "message": "Task cannot be canceled",
    "data": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_CANCELABLE",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
          "state": "TASK_STATE_CANCELED"
        }
      }
    ]
  }
}

### 4 · SendMessage: to the canceled task
POST /a2a/jsonrpc HTTP/1.1
Host: localhost:41241
Content-Type: application/json
A2A-Version: 1.0

{
  "jsonrpc": "2.0",
  "id": 4,
  "method": "SendMessage",
  "params": {
    "message": {
      "messageId": "766bad07-34c2-4a80-83cc-0f2793fdcab8",
      "contextId": "9b584e1f-b948-453f-9250-18314071afc7",
      "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
      "role": "ROLE_USER",
      "parts": [
        {
          "text": "Try again"
        }
      ]
    }
  }
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 4,
  "error": {
    "code": -32004,
    "message": "This operation is not supported",
    "data": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "UNSUPPORTED_OPERATION",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "f22ed7af-848d-4f4d-8cd1-3204d1e1bbaf",
          "state": "TASK_STATE_CANCELED"
        }
      }
    ]
  }
}