Run Message Workflow

curl --request POST \
  --url https://api.example.com/a2a/workflows/{id}/v1/message:send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": "<string>",
  "params": {
    "message": {
      "messageId": "<string>",
      "parts": [
        {
          "text": "<string>",
          "kind": "text",
          "metadata": {}
        }
      ],
      "contextId": "<string>",
      "extensions": [
        "<string>"
      ],
      "kind": "message",
      "metadata": {},
      "referenceTaskIds": [
        "<string>"
      ],
      "taskId": "<string>",
      "agentId": "<string>"
    },
    "configuration": {
      "acceptedOutputModes": [
        "<string>"
      ],
      "blocking": true,
      "historyLength": 123,
      "pushNotificationConfig": {
        "url": "<string>",
        "authentication": {
          "schemes": [
            "<string>"
          ],
          "credentials": "<string>"
        },
        "id": "<string>",
        "token": "<string>"
      }
    },
    "metadata": {}
  },
  "jsonrpc": "2.0",
  "method": "message/send"
}
'

import requests

url = "https://api.example.com/a2a/workflows/{id}/v1/message:send"

payload = {
    "id": "<string>",
    "params": {
        "message": {
            "messageId": "<string>",
            "parts": [
                {
                    "text": "<string>",
                    "kind": "text",
                    "metadata": {}
                }
            ],
            "contextId": "<string>",
            "extensions": ["<string>"],
            "kind": "message",
            "metadata": {},
            "referenceTaskIds": ["<string>"],
            "taskId": "<string>",
            "agentId": "<string>"
        },
        "configuration": {
            "acceptedOutputModes": ["<string>"],
            "blocking": True,
            "historyLength": 123,
            "pushNotificationConfig": {
                "url": "<string>",
                "authentication": {
                    "schemes": ["<string>"],
                    "credentials": "<string>"
                },
                "id": "<string>",
                "token": "<string>"
            }
        },
        "metadata": {}
    },
    "jsonrpc": "2.0",
    "method": "message/send"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    id: '<string>',
    params: {
      message: {
        messageId: '<string>',
        parts: [{text: '<string>', kind: 'text', metadata: {}}],
        contextId: '<string>',
        extensions: ['<string>'],
        kind: 'message',
        metadata: {},
        referenceTaskIds: ['<string>'],
        taskId: '<string>',
        agentId: '<string>'
      },
      configuration: {
        acceptedOutputModes: ['<string>'],
        blocking: true,
        historyLength: 123,
        pushNotificationConfig: {
          url: '<string>',
          authentication: {schemes: ['<string>'], credentials: '<string>'},
          id: '<string>',
          token: '<string>'
        }
      },
      metadata: {}
    },
    jsonrpc: '2.0',
    method: 'message/send'
  })
};

fetch('https://api.example.com/a2a/workflows/{id}/v1/message:send', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/a2a/workflows/{id}/v1/message:send",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'id' => '<string>',
    'params' => [
        'message' => [
                'messageId' => '<string>',
                'parts' => [
                                [
                                                                'text' => '<string>',
                                                                'kind' => 'text',
                                                                'metadata' => [
                                                                                                                                
                                                                ]
                                ]
                ],
                'contextId' => '<string>',
                'extensions' => [
                                '<string>'
                ],
                'kind' => 'message',
                'metadata' => [
                                
                ],
                'referenceTaskIds' => [
                                '<string>'
                ],
                'taskId' => '<string>',
                'agentId' => '<string>'
        ],
        'configuration' => [
                'acceptedOutputModes' => [
                                '<string>'
                ],
                'blocking' => true,
                'historyLength' => 123,
                'pushNotificationConfig' => [
                                'url' => '<string>',
                                'authentication' => [
                                                                'schemes' => [
                                                                                                                                '<string>'
                                                                ],
                                                                'credentials' => '<string>'
                                ],
                                'id' => '<string>',
                                'token' => '<string>'
                ]
        ],
        'metadata' => [
                
        ]
    ],
    'jsonrpc' => '2.0',
    'method' => 'message/send'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.example.com/a2a/workflows/{id}/v1/message:send"

	payload := strings.NewReader("{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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))

}

HttpResponse<String> response = Unirest.post("https://api.example.com/a2a/workflows/{id}/v1/message:send")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.example.com/a2a/workflows/{id}/v1/message:send")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}"

response = http.request(request)
puts response.read_body

{
  "id": "request-123",
  "jsonrpc": "2.0",
  "result": {
    "contextId": "context-789",
    "id": "task-456",
    "kind": "task",
    "status": {
      "state": "completed"
    }
  }
}

{
  "detail": "Unauthenticated access",
  "error_code": "UNAUTHENTICATED"
}

{
  "detail": "Insufficient permissions"
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>",
      "input": "<unknown>",
      "ctx": {}
    }
  ]
}

POST

a2a

workflows

{id}

message:send

Run Message Workflow

curl --request POST \
  --url https://api.example.com/a2a/workflows/{id}/v1/message:send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": "<string>",
  "params": {
    "message": {
      "messageId": "<string>",
      "parts": [
        {
          "text": "<string>",
          "kind": "text",
          "metadata": {}
        }
      ],
      "contextId": "<string>",
      "extensions": [
        "<string>"
      ],
      "kind": "message",
      "metadata": {},
      "referenceTaskIds": [
        "<string>"
      ],
      "taskId": "<string>",
      "agentId": "<string>"
    },
    "configuration": {
      "acceptedOutputModes": [
        "<string>"
      ],
      "blocking": true,
      "historyLength": 123,
      "pushNotificationConfig": {
        "url": "<string>",
        "authentication": {
          "schemes": [
            "<string>"
          ],
          "credentials": "<string>"
        },
        "id": "<string>",
        "token": "<string>"
      }
    },
    "metadata": {}
  },
  "jsonrpc": "2.0",
  "method": "message/send"
}
'

import requests

url = "https://api.example.com/a2a/workflows/{id}/v1/message:send"

payload = {
    "id": "<string>",
    "params": {
        "message": {
            "messageId": "<string>",
            "parts": [
                {
                    "text": "<string>",
                    "kind": "text",
                    "metadata": {}
                }
            ],
            "contextId": "<string>",
            "extensions": ["<string>"],
            "kind": "message",
            "metadata": {},
            "referenceTaskIds": ["<string>"],
            "taskId": "<string>",
            "agentId": "<string>"
        },
        "configuration": {
            "acceptedOutputModes": ["<string>"],
            "blocking": True,
            "historyLength": 123,
            "pushNotificationConfig": {
                "url": "<string>",
                "authentication": {
                    "schemes": ["<string>"],
                    "credentials": "<string>"
                },
                "id": "<string>",
                "token": "<string>"
            }
        },
        "metadata": {}
    },
    "jsonrpc": "2.0",
    "method": "message/send"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    id: '<string>',
    params: {
      message: {
        messageId: '<string>',
        parts: [{text: '<string>', kind: 'text', metadata: {}}],
        contextId: '<string>',
        extensions: ['<string>'],
        kind: 'message',
        metadata: {},
        referenceTaskIds: ['<string>'],
        taskId: '<string>',
        agentId: '<string>'
      },
      configuration: {
        acceptedOutputModes: ['<string>'],
        blocking: true,
        historyLength: 123,
        pushNotificationConfig: {
          url: '<string>',
          authentication: {schemes: ['<string>'], credentials: '<string>'},
          id: '<string>',
          token: '<string>'
        }
      },
      metadata: {}
    },
    jsonrpc: '2.0',
    method: 'message/send'
  })
};

fetch('https://api.example.com/a2a/workflows/{id}/v1/message:send', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/a2a/workflows/{id}/v1/message:send",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'id' => '<string>',
    'params' => [
        'message' => [
                'messageId' => '<string>',
                'parts' => [
                                [
                                                                'text' => '<string>',
                                                                'kind' => 'text',
                                                                'metadata' => [
                                                                                                                                
                                                                ]
                                ]
                ],
                'contextId' => '<string>',
                'extensions' => [
                                '<string>'
                ],
                'kind' => 'message',
                'metadata' => [
                                
                ],
                'referenceTaskIds' => [
                                '<string>'
                ],
                'taskId' => '<string>',
                'agentId' => '<string>'
        ],
        'configuration' => [
                'acceptedOutputModes' => [
                                '<string>'
                ],
                'blocking' => true,
                'historyLength' => 123,
                'pushNotificationConfig' => [
                                'url' => '<string>',
                                'authentication' => [
                                                                'schemes' => [
                                                                                                                                '<string>'
                                                                ],
                                                                'credentials' => '<string>'
                                ],
                                'id' => '<string>',
                                'token' => '<string>'
                ]
        ],
        'metadata' => [
                
        ]
    ],
    'jsonrpc' => '2.0',
    'method' => 'message/send'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.example.com/a2a/workflows/{id}/v1/message:send"

	payload := strings.NewReader("{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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))

}

HttpResponse<String> response = Unirest.post("https://api.example.com/a2a/workflows/{id}/v1/message:send")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.example.com/a2a/workflows/{id}/v1/message:send")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"id\": \"<string>\",\n  \"params\": {\n    \"message\": {\n      \"messageId\": \"<string>\",\n      \"parts\": [\n        {\n          \"text\": \"<string>\",\n          \"kind\": \"text\",\n          \"metadata\": {}\n        }\n      ],\n      \"contextId\": \"<string>\",\n      \"extensions\": [\n        \"<string>\"\n      ],\n      \"kind\": \"message\",\n      \"metadata\": {},\n      \"referenceTaskIds\": [\n        \"<string>\"\n      ],\n      \"taskId\": \"<string>\",\n      \"agentId\": \"<string>\"\n    },\n    \"configuration\": {\n      \"acceptedOutputModes\": [\n        \"<string>\"\n      ],\n      \"blocking\": true,\n      \"historyLength\": 123,\n      \"pushNotificationConfig\": {\n        \"url\": \"<string>\",\n        \"authentication\": {\n          \"schemes\": [\n            \"<string>\"\n          ],\n          \"credentials\": \"<string>\"\n        },\n        \"id\": \"<string>\",\n        \"token\": \"<string>\"\n      }\n    },\n    \"metadata\": {}\n  },\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"message/send\"\n}"

response = http.request(request)
puts response.read_body

{
  "id": "request-123",
  "jsonrpc": "2.0",
  "result": {
    "contextId": "context-789",
    "id": "task-456",
    "kind": "task",
    "status": {
      "state": "completed"
    }
  }
}

{
  "detail": "Unauthenticated access",
  "error_code": "UNAUTHENTICATED"
}

{
  "detail": "Insufficient permissions"
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>",
      "input": "<unknown>",
      "ctx": {}
    }
  ]
}

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

X-User-ID

string

Optional user ID for anonymous attribution. Authenticated requests use the identity from the credential.

Path Parameters

string

required

Body

application/json

Represents a JSON-RPC request for the message/send method.

required

params

MessageSendParams · object

required

Defines the parameters for a request to send a message to an agent. This can be used to create a new task, continue an existing one, or restart a task.

Show child attributes

jsonrpc

string

default:2.0

Allowed value: "2.0"

method

string

default:message/send

Allowed value: "message/send"

Response

Message sent successfully

Represents a successful JSON-RPC response for the message/send method.

result

Task · object

required

Represents a single, stateful operation or conversation between a client and an agent.

Task
Message

Show child attributes

jsonrpc

string

default:2.0

Allowed value: "2.0"

Get Workflow Card Stream Message Workflow

⌘I

Agno SDK Reference

AgentOS API Reference

Agno CLI

Agno Infra CLI

Run Message Workflow

Authorizations

Headers

Path Parameters

Body

Response