Send a message (A2A REST)

cURL

curl --request POST \
  --url https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Tenant-Name: <api-key>' \
  --data '
{
  "message": {
    "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
    "role": "ROLE_USER",
    "parts": [
      {
        "text": "What is the ICD-10 code for asthma?"
      }
    ]
  }
}
'

import { CortiClient, CortiEnvironment } from "@corti/sdk";

const client = new CortiClient({
    environment: CortiEnvironment.Eu,
    auth: {
        clientId: "YOUR_CLIENT_ID",
        clientSecret: "YOUR_CLIENT_SECRET"
    },
    tenantName: "YOUR_TENANT_NAME"
});
await client.agentic.agents.sendMessage("agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40", {
    message: {
        messageId: "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        role: "ROLE_USER",
        parts: [{
                text: "What is the ICD-10 code for asthma?"
            }]
    }
});

using Corti;

var client = new CortiClient(
    "TENANT_NAME",
    CortiClientEnvironment.Eu,
    new CortiClientAuth.ClientCredentials("client_id", "client_secret")
);
await client.Agentic.Agents.SendMessageAsync(
    "agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40",
    new AgenticAgentsSendMessageRequest
    {
        Message = new CommonMessage
        {
            MessageId = "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
            Role = CommonRole.RoleUser,
            Parts = new List<CommonPart>()
            {
                new CommonPart { Text = "What is the ICD-10 code for asthma?" },
            },
        },
    }
);

import requests

url = "https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send"

payload = { "message": {
        "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        "role": "ROLE_USER",
        "parts": [{ "text": "What is the ICD-10 code for asthma?" }]
    } }
headers = {
    "Authorization": "Bearer <token>",
    "Tenant-Name": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/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([
    'message' => [
        'messageId' => 'msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73',
        'role' => 'ROLE_USER',
        'parts' => [
                [
                                'text' => 'What is the ICD-10 code for asthma?'
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "Tenant-Name: <api-key>"
  ],
]);

$response = curl_exec($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.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send"

	payload := strings.NewReader("{\n  \"message\": {\n    \"messageId\": \"msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73\",\n    \"role\": \"ROLE_USER\",\n    \"parts\": [\n      {\n        \"text\": \"What is the ICD-10 code for asthma?\"\n      }\n    ]\n  }\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Tenant-Name", "<api-key>")
	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.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send")
  .header("Authorization", "Bearer <token>")
  .header("Tenant-Name", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"message\": {\n    \"messageId\": \"msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73\",\n    \"role\": \"ROLE_USER\",\n    \"parts\": [\n      {\n        \"text\": \"What is the ICD-10 code for asthma?\"\n      }\n    ]\n  }\n}")
  .asString();

{
  "task": {
    "id": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62",
    "contextId": "ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51",
    "status": {
      "state": "TASK_STATE_COMPLETED",
      "timestamp": "2026-05-19T12:00:01Z",
      "message": {
        "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        "contextId": "ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51",
        "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "J45.909"
          }
        ]
      }
    },
    "artifacts": [
      {
        "artifactId": "art.0192f4c8-6a9e-7f72-a35e-70c1ac6fbe84",
        "parts": [
          {
            "text": "J45.909"
          }
        ]
      }
    ],
    "metadata": {
      "$usage": {
        "model": "corti-default",
        "inputTokens": 100,
        "outputTokens": 20,
        "cachedInputTokens": 64,
        "cacheCreationInputTokens": 0,
        "totalTokens": 120,
        "credits": 1.2
      }
    }
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

POST

agentic

agents

{agentId}

a2a

message:send

cURL

curl --request POST \
  --url https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Tenant-Name: <api-key>' \
  --data '
{
  "message": {
    "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
    "role": "ROLE_USER",
    "parts": [
      {
        "text": "What is the ICD-10 code for asthma?"
      }
    ]
  }
}
'

import { CortiClient, CortiEnvironment } from "@corti/sdk";

const client = new CortiClient({
    environment: CortiEnvironment.Eu,
    auth: {
        clientId: "YOUR_CLIENT_ID",
        clientSecret: "YOUR_CLIENT_SECRET"
    },
    tenantName: "YOUR_TENANT_NAME"
});
await client.agentic.agents.sendMessage("agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40", {
    message: {
        messageId: "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        role: "ROLE_USER",
        parts: [{
                text: "What is the ICD-10 code for asthma?"
            }]
    }
});

using Corti;

var client = new CortiClient(
    "TENANT_NAME",
    CortiClientEnvironment.Eu,
    new CortiClientAuth.ClientCredentials("client_id", "client_secret")
);
await client.Agentic.Agents.SendMessageAsync(
    "agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40",
    new AgenticAgentsSendMessageRequest
    {
        Message = new CommonMessage
        {
            MessageId = "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
            Role = CommonRole.RoleUser,
            Parts = new List<CommonPart>()
            {
                new CommonPart { Text = "What is the ICD-10 code for asthma?" },
            },
        },
    }
);

import requests

url = "https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send"

payload = { "message": {
        "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        "role": "ROLE_USER",
        "parts": [{ "text": "What is the ICD-10 code for asthma?" }]
    } }
headers = {
    "Authorization": "Bearer <token>",
    "Tenant-Name": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/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([
    'message' => [
        'messageId' => 'msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73',
        'role' => 'ROLE_USER',
        'parts' => [
                [
                                'text' => 'What is the ICD-10 code for asthma?'
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "Tenant-Name: <api-key>"
  ],
]);

$response = curl_exec($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.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send"

	payload := strings.NewReader("{\n  \"message\": {\n    \"messageId\": \"msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73\",\n    \"role\": \"ROLE_USER\",\n    \"parts\": [\n      {\n        \"text\": \"What is the ICD-10 code for asthma?\"\n      }\n    ]\n  }\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Tenant-Name", "<api-key>")
	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.{environment}.corti.app/v2/agentic/agents/{agentId}/a2a/message:send")
  .header("Authorization", "Bearer <token>")
  .header("Tenant-Name", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"message\": {\n    \"messageId\": \"msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73\",\n    \"role\": \"ROLE_USER\",\n    \"parts\": [\n      {\n        \"text\": \"What is the ICD-10 code for asthma?\"\n      }\n    ]\n  }\n}")
  .asString();

{
  "task": {
    "id": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62",
    "contextId": "ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51",
    "status": {
      "state": "TASK_STATE_COMPLETED",
      "timestamp": "2026-05-19T12:00:01Z",
      "message": {
        "messageId": "msg.0192f4c8-5f8d-7e61-924d-6fb09b5ead73",
        "contextId": "ctx.0192f4c8-3d6b-7c4f-a02b-4d9e7f3c8b51",
        "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "J45.909"
          }
        ]
      }
    },
    "artifacts": [
      {
        "artifactId": "art.0192f4c8-6a9e-7f72-a35e-70c1ac6fbe84",
        "parts": [
          {
            "text": "J45.909"
          }
        ]
      }
    ],
    "metadata": {
      "$usage": {
        "model": "corti-default",
        "inputTokens": 100,
        "outputTokens": 20,
        "cachedInputTokens": 64,
        "cacheCreationInputTokens": 0,
        "totalTokens": 120,
        "credits": 1.2
      }
    }
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found.",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "task.0192f4c8-4e7c-7d50-b13c-5eaf8a4d9c62"
        }
      }
    ]
  }
}

Authorizations

Authorization

string

header

required

OAuth 2.0 / OIDC bearer token.

Tenant-Name

string

header

required

The tenant the request operates within.

Headers

A2A-Version

string

default:1.0

A2A protocol version in Major.Minor form (A2A §3.6). Optional; defaults to 1.0 when absent. This surface implements 1.0 only. Patch versions MUST NOT be sent and are not considered during negotiation.

Pattern: ^\d+\.\d+$

Path Parameters

agentId

string<agent-id>

required

Agent identifier (prefixed UUIDv7). Agent identifier. Accepts agt.<uuidv7> or a bare UUIDv7 on input; always returned prefixed.

Pattern: ^(agt\.)?[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$

Example:

"agt.0192f4c8-2c5a-7b3e-9f1a-3c8d6e2b7a40"

Body

application/json

The message to send to the agent.

Request body for sending a message to an agent.

message

object

required

An A2A message — an ordered list of content parts with a role.

Show child attributes

configuration

object

Per-request options controlling how a message is processed.

Show child attributes

metadata

object

Free-form request metadata.

Example:

{
  "requestSource": "mobile",
  "traceId": "trace.abc123"
}

tenant

string

Optional. Opaque routing identifier. Must match the tenant value from the selected AgentInterface in the Agent Card when that field is set.

Response

The resulting task or agent message.

Option 1
Option 2

Exactly one of task or message is present.

task

object

required

An A2A task — a unit of agent work with status, history, and artifacts.

Show child attributes

message

object

An A2A message — an ordered list of content parts with a role.

Show child attributes

Web Socket APIs

REST APIs

Agentic APIs v2 (beta)

Agentic APIs v1 (deprecated)

Admin APIs

Corti Models APIs

Errors

Authorizations

Headers

Path Parameters

Body

Response