Send a message (A2A JSON-RPC)

curl --request POST \
  --url https://mesh.svantic.com/send \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "method": "message/send",
  "params": {
    "message": {
      "messageId": "01JQ_EXAMPLE",
      "role": "user",
      "parts": [
        {
          "kind": "text",
          "text": "Summarize the attached document."
        }
      ]
    }
  },
  "id": 1
}
'

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'message/send',
    params: {
      message: {
        messageId: '01JQ_EXAMPLE',
        role: 'user',
        parts: [{kind: 'text', text: 'Summarize the attached document.'}]
      }
    },
    id: 1
  })
};

fetch('https://mesh.svantic.com/send', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://mesh.svantic.com/send"

payload = {
    "jsonrpc": "2.0",
    "method": "message/send",
    "params": { "message": {
            "messageId": "01JQ_EXAMPLE",
            "role": "user",
            "parts": [
                {
                    "kind": "text",
                    "text": "Summarize the attached document."
                }
            ]
        } },
    "id": 1
}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://mesh.svantic.com/send"

	payload := strings.NewReader("{\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"01JQ_EXAMPLE\",\n      \"role\": \"user\",\n      \"parts\": [\n        {\n          \"kind\": \"text\",\n          \"text\": \"Summarize the attached document.\"\n        }\n      ]\n    }\n  },\n  \"id\": 1\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

{
  "jsonrpc": "2.0",
  "result": {
    "message": {
      "messageId": "01JQ_REPLY",
      "role": "agent",
      "parts": [
        {
          "kind": "text",
          "text": "Here is a concise summary…"
        }
      ]
    }
  },
  "id": 1
}

{
  "error": "Invalid request body",
  "code": "BAD_REQUEST"
}

{
  "error": "Invalid or expired token",
  "code": "unauthorized"
}

{
  "error": "JWT does not include the required scope for this operation",
  "code": "forbidden"
}

{
  "error": "Not found",
  "code": "NOT_FOUND",
  "request_id": "req_01EXAMPLE",
  "timestamp": "2026-03-31T12:00:00.000Z"
}

{
  "error": "Request timeout",
  "code": "REQUEST_TIMEOUT"
}

{
  "error": "Internal server error",
  "code": "INTERNAL_ERROR",
  "request_id": "req_01EXAMPLE",
  "timestamp": "2026-03-31T12:00:00.000Z"
}

{
  "error": "Bad gateway",
  "code": "BAD_GATEWAY"
}

{
  "error": "Service temporarily unavailable",
  "code": "SERVICE_UNAVAILABLE"
}