Deploy API: A2A Server

A2A protocol endpoints for agent-to-agent communication

POST /a2a

Deploy API: A2A Server

cURL

curl --request POST \
  --url http://127.0.0.1:8765/a2a \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "jsonrpc": "<string>",
  "method": "<string>",
  "id": "<string>",
  "params.message.role": "<string>",
  "params.message.parts": [
    {}
  ]
}
'

import requests

url = "http://127.0.0.1:8765/a2a"

payload = {
    "jsonrpc": "<string>",
    "method": "<string>",
    "id": "<string>",
    "params.message.role": "<string>",
    "params.message.parts": [{}]
}
headers = {
    "X-API-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'X-API-Key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    jsonrpc: '<string>',
    method: '<string>',
    id: '<string>',
    'params.message.role': '<string>',
    'params.message.parts': [{}]
  })
};

fetch('http://127.0.0.1:8765/a2a', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_PORT => "8765",
  CURLOPT_URL => "http://127.0.0.1:8765/a2a",
  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([
    'jsonrpc' => '<string>',
    'method' => '<string>',
    'id' => '<string>',
    'params.message.role' => '<string>',
    'params.message.parts' => [
        [
                
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-API-Key: <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 := "http://127.0.0.1:8765/a2a"

	payload := strings.NewReader("{\n  \"jsonrpc\": \"<string>\",\n  \"method\": \"<string>\",\n  \"id\": \"<string>\",\n  \"params.message.role\": \"<string>\",\n  \"params.message.parts\": [\n    {}\n  ]\n}")

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

	req.Header.Add("X-API-Key", "<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("http://127.0.0.1:8765/a2a")
  .header("X-API-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"jsonrpc\": \"<string>\",\n  \"method\": \"<string>\",\n  \"id\": \"<string>\",\n  \"params.message.role\": \"<string>\",\n  \"params.message.parts\": [\n    {}\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("http://127.0.0.1:8765/a2a")

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

request = Net::HTTP::Post.new(url)
request["X-API-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"jsonrpc\": \"<string>\",\n  \"method\": \"<string>\",\n  \"id\": \"<string>\",\n  \"params.message.role\": \"<string>\",\n  \"params.message.parts\": [\n    {}\n  ]\n}"

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

A2A API

A2A (Agent-to-Agent) protocol endpoints for agents deployed via A2A(agent).get_router().

Base URL + Playground

# Start A2A server
from praisonaiagents import Agent
from praisonaiagents.a2a import A2A
import uvicorn

agent = Agent(instructions="You are a helpful assistant")
app = A2A(agent).get_router()
uvicorn.run(app, host="0.0.0.0", port=8000)

Base URL: http://localhost:8000

Endpoints

GET /.well-known/agent.json

Retrieve the Agent Card for discovery.

none · none

No parameters required.

curl

curl http://localhost:8000/.well-known/agent.json

import requests

response = requests.get("http://localhost:8000/.well-known/agent.json")
agent_card = response.json()
print(f"Agent: {agent_card['name']}")
print(f"URL: {agent_card['url']}")
print(f"Skills: {[s['name'] for s in agent_card['skills']]}")

const response = await fetch("http://localhost:8000/.well-known/agent.json");
const agentCard = await response.json();
console.log(`Agent: ${agentCard.name}`);
console.log(`URL: ${agentCard.url}`);

Response:

{
  "name": "Assistant",
  "description": "Helpful AI Assistant",
  "url": "http://localhost:8000/a2a",
  "version": "1.0.0",
  "capabilities": {
    "streaming": true,
    "pushNotifications": false,
    "stateTransitionHistory": false
  },
  "skills": [
    {
      "id": "chat",
      "name": "Chat",
      "description": "General conversation"
    }
  ]
}

GET /status

Check server status.

none · none

No parameters required.

curl

curl http://localhost:8000/status

import requests

response = requests.get("http://localhost:8000/status")
status = response.json()
print(f"Status: {status['status']}")
print(f"Agent: {status['name']}")

Response:

{
  "status": "ok",
  "name": "Assistant",
  "version": "1.0.0"
}

POST /a2a

Send JSON-RPC messages to the agent.

jsonrpc · string · required

JSON-RPC version (must be “2.0”)

method · string · required

A2A method name (message/send)

id · string · required

Request ID

params.message.role · string · required

Message role (“user”)

params.message.parts · array · required

Message parts array

curl

curl -X POST http://localhost:8000/a2a \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "message/send",
    "id": "request-123",
    "params": {
      "message": {
        "role": "user",
        "parts": [
          {"type": "text", "text": "Hello, agent!"}
        ]
      }
    }
  }'

import requests

message = {
    "jsonrpc": "2.0",
    "method": "message/send",
    "id": "request-123",
    "params": {
        "message": {
            "role": "user",
            "parts": [{"type": "text", "text": "Hello, agent!"}]
        }
    }
}
response = requests.post("http://localhost:8000/a2a", json=message)
result = response.json()["result"]
print(f"Agent: {result['message']['parts'][0]['text']}")

const message = {
  jsonrpc: "2.0",
  method: "message/send",
  id: "request-123",
  params: {
    message: {
      role: "user",
      parts: [{ type: "text", text: "Hello, agent!" }]
    }
  }
};

const response = await fetch("http://localhost:8000/a2a", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify(message)
});

const { result } = await response.json();
console.log(`Agent: ${result.message.parts[0].text}`);

Response:

{
  "jsonrpc": "2.0",
  "id": "request-123",
  "result": {
    "message": {
      "role": "agent",
      "parts": [
        {"type": "text", "text": "Hello! How can I help you today?"}
      ]
    }
  }
}

Message Part Types

Type	Fields	Description
text	text	Plain text content
file	uri, mimeType	File attachment

Errors

A2A errors follow JSON-RPC 2.0 format:

{
  "jsonrpc": "2.0",
  "id": "request-123",
  "error": {
    "code": -32600,
    "message": "Invalid request"
  }
}

Code	Message
-32700	Parse error
-32600	Invalid request
-32601	Method not found
-32602	Invalid params
-32603	Internal error

Related

• A2A Server - Deploy agents as A2A server
• AGUI API - AG-UI protocol endpoints
• Agents API - HTTP REST endpoints